WO2021007752A1

WO2021007752A1 - Return-to-source method and related device in content delivery network

Info

Publication number: WO2021007752A1
Application number: PCT/CN2019/096028
Authority: WO
Inventors: 周香鹤
Original assignee: 华为技术有限公司
Priority date: 2019-07-15
Filing date: 2019-07-15
Publication date: 2021-01-21
Also published as: CN112513830A

Abstract

Disclosed in the embodiments of the present invention are a return-to-source method and a related device in a content delivery network. The method comprises the following steps: an edge cache node receives a cache refreshing request transmitted by a control platform, wherein the cache refreshing request carries the uniform resource locator (URL) of a resource to be refreshed; the edge cache node transmits a return-to-source request to a central cache node, wherein the return-to-source request carries the URL of the resource to be refreshed and a refresh time of the resource to be refreshed. The present invention can avoid the occurrence of the case that the central cache node returns an old resource to the edge cache node.

Description

Back-to-source method and related device in content distribution network

Technical field

This application relates to the field of content distribution networks, and in particular to a back-to-source method and related devices in a content distribution network.

Background technique

The Content Delivery Network (CDN) includes multiple cache nodes, and the multiple cache nodes include multiple edge cache nodes and at least one central cache node. The edge cache nodes obtain the resources of the source station through the central cache node. When a user visits the origin site, relying on the edge cache nodes deployed in various places can obtain the required content from the nearby edge cache nodes, thereby reducing network congestion and improving user access response speed and hit rate.

After the resources of the origin site are updated, the edge cache nodes and central cache nodes of the CDN need to perform corresponding resource updates. In the prior art, the edge cache node sends back a source request to the central cache node, and obtains updated resources from the central cache node. If the central cache node stores updated resources, it will directly return the updated resources to the edge cache node. If the resources cached by the central cache node are old resources before the source site updates the resources, the central cache node may send the updated resources to the edge cache node. Returning to the old resources then makes the client unable to obtain the updated resources from the edge cache node, resulting in a poor user experience.

Summary of the invention

In order to solve the problems of the prior art, embodiments of the present invention provide a back-to-origin method and related devices in a content distribution network, which can avoid the situation that the central cache node returns old resources to the edge cache node.

In the first aspect, an embodiment of the present invention provides a back-to-origin method in a content distribution network. The method includes the following steps: an edge cache node receives a cache refresh request sent by a control platform, and the cache refresh request carries a uniform resource locator of the resource to be refreshed URL, the edge cache node sends a back-to-origin request to the central cache node, and the back-to-origin request carries the URL of the resource to be refreshed and the refresh time of the resource to be refreshed.

Since the back-to-origin request carries the refresh time of the resource to be refreshed and the URL of the resource to be refreshed, after the central cache node receives the back-to-origin request, when the URL of the resource to be refreshed hits the cache, it will confirm the cached according to the refresh time of the resource to be refreshed. Whether the resource to be refreshed is the old resource before the source station performs the resource update can avoid the situation that the central cache node directly sends the old resource to the edge cache node when the URL of the resource to be refreshed hits the cache.

Optionally, the refresh time is carried in the cache refresh request, and the refresh time is set by the control platform.

Optionally, the control platform uses the time when the user triggers the refresh instruction for the URL of the resource to be refreshed on the control platform as the refresh time of the resource to be refreshed.

The refresh time is uniformly set by the control platform, and the edge cache node and the central cache node only need to judge based on the received refresh time, which makes the processing flow relatively simple.

Optionally, the refresh time is the point in time when the edge cache node receives the cache refresh request.

Compared with the refresh time set by the control platform, the time when the edge cache node receives the cache refresh request is used as the refresh time. The refresh time does not need to be sent by the control platform to the edge cache node, so bandwidth can be saved. At the same time, due to the setting of the control platform The refresh time needs to be transmitted over the network, so the time when the edge cache node receives the cache refresh request is later than the refresh time set by the control platform, which can more accurately reflect the refresh time of the resource to be refreshed at the edge cache node.

Optionally, before the edge cache node sends the back-to-origin request to the central cache node, the back-to-origin method in the content distribution network further includes the following steps: the edge cache node receives the first resource access request sent by the client, and correspondingly, the edge cache The node sends back the source request to the central cache node in response to the first resource access request.

In CDN, a fee is charged for each return to the source. Therefore, a specific edge cache node sends a return request after receiving the resource access request sent by the client. There is no need for all edge cache nodes to issue a return request, which can reduce return to the source. Times, cost savings.

Optionally, the first resource access request carries the URL of the resource to be accessed, and the edge cache node sends back the source request to the central cache node in response to the resource access request, which specifically includes the following steps: the edge cache node determines the URL of the resource to be accessed and the resource to be accessed. When the URL of the refresh resource matches and the URL of the resource to be accessed does not hit the cache, a request is sent back to the central cache node.

When the edge cache node determines that the URL of the resource to be accessed matches the URL of the resource to be refreshed and the URL of the resource to be accessed does not hit the cache, it sends a back-to-origin request carrying the URL of the resource to be refreshed and the refresh time to the central cache node. It can be ensured that the central cache node can determine whether to return to the source site node according to the refresh time after the edge cache node obtains the cache refresh request, which can avoid sending old resources to the edge cache node.

Optionally, the resource access request carries the URL of the resource to be accessed, and the edge cache node sends back the source request to the central cache node in response to the resource access request, and further includes the following steps: the edge cache node determines the URL of the resource to be accessed and the resource to be refreshed When the URL of the URL matches, the URL of the resource to be accessed hits the cache, and the refresh time is later than the cache time, a back-to-origin request is sent to the central cache node, where the cache time is the time point at which the edge cache node caches the resource to be accessed.

When the edge cache node determines that the URL of the resource to be accessed matches the URL of the resource to be refreshed, the URL of the resource to be accessed hits the cache, and the refresh time is later than the cache time, it sends the URL and URL of the resource to be refreshed to the central cache node. The refresh time return request can ensure that the central cache node can determine whether to return to the origin node based on the refresh time after the edge cache node obtains the cache refresh request, which can avoid sending old resources to the edge cache node.

Optionally, the edge cache node is provided with a refresh table, and after the edge cache node receives the cache refresh request sent by the control platform, the method further includes the following steps: the edge cache node records the URL and refresh time of the resource to be refreshed in the refresh table.

By refreshing the table to record the URL and refresh time of the resource to be refreshed, the edge cache node only needs to query whether the refresh table records the URL of the resource to be refreshed to know whether the edge cache node has received the cache refresh request sent by the control platform, which can effectively improve the processing speed .

Optionally, after the edge cache node records the URL and refresh time of the resource to be refreshed in the refresh table, the method further includes: the edge cache node deletes the URL and refresh time of the resource to be refreshed recorded in the refresh table after a predetermined time.

Since refreshing the table will occupy storage space and memory, the timing deletion mechanism can save the storage space and memory resources of edge cache nodes.

Optionally, after the edge cache node deletes the URL and refresh time of the resource to be refreshed recorded in the refresh table after a predetermined time, the method further includes: the edge cache node receives a second resource access request sent by the client, and the second resource access The request carries the URL of the resource to be accessed. When the edge cache node determines that the URL of the resource to be accessed is not in the refresh table and the URL of the resource to be accessed hits the cache, the edge cache node sends the resource access request response information to the client, and the resource access request response Information carries resources to be accessed.

Since the URL of the resource to be refreshed is not recorded in the refresh table, the edge cache node has not received a cache refresh request for the URL before determining, and can directly return the resource to be accessed to the client at this time.

By deleting the URL and refresh time of the resource to be refreshed recorded in the refresh table after a predetermined time, you can ensure that the refresh record of the resource to be refreshed is deleted in time after the resource to be refreshed is refreshed across the CDN network, thereby avoiding affecting the download of the resource to be refreshed. A round of cache refresh requests.

Optionally, the edge cache node determines that the URL of the resource to be accessed is the same as the URL of the resource to be refreshed, or when it is determined that the URL of the resource to be refreshed is the prefix of the URL of the resource to be accessed, determines the URL of the resource to be accessed and the URL of the resource to be refreshed. The URL of the refresh resource matches.

In a second aspect, an embodiment of the present invention provides a back-to-origin method in a content distribution network, including the following steps: a central cache node receives a first back-to-origin request sent by an edge cache node, and the first back-to-origin request carries the URL of the resource to be refreshed And the refresh time of the resource to be refreshed, the central cache node compares the refresh time with the cache time of the resource to be refreshed when the URL of the resource to be refreshed hits the cache, and when it is determined that the refresh time is later than the cache time, The origin node sends a second back-to-origin request.

Optionally, the refresh time is carried in the cache refresh request received by the edge cache node from the control platform, and the refresh time is set by the control platform.

Optionally, the refresh time is the point in time when the edge cache node receives the first cache refresh request sent by the control platform.

Optionally, before the central cache node sends the second back-to-origin request to the source site node, the method further includes: the central cache node receives a second cache refresh request sent by the control platform, where the second cache refresh request carries the URL of the resource to be refreshed, The central cache node determines that the time when the second cache refresh request is received is later than the cache time.

When the central cache node confirms that the refresh time is later than the cache time, and the central cache node judges that the time when the second cache refresh request is received is later than the cache time, it sends the second back-to-origin request to the origin node, which can effectively reduce Number of return to source.

Optionally, the central cache node is provided with a refresh table, and after the central cache node receives the first back-to-origin request sent by the edge cache node, the method further includes: the central cache node records the URL and refresh time of the resource to be refreshed in the refresh table.

By refreshing the table to record the URL and refresh time of the resource to be refreshed, the central cache node only needs to query whether the refresh table records the URL of the resource to be refreshed to know whether the central cache node has received the cache refresh request sent by the control platform, which can effectively improve the processing speed .

Optionally, after the central cache node records the URL and refresh time of the resource to be refreshed in the refresh table, the method further includes: the central cache node deletes the URL and refresh time of the resource to be refreshed recorded in the refresh table after a predetermined time.

Optionally, after the central cache node deletes the URL and refresh time of the resource to be refreshed recorded in the refresh table after a predetermined time, the method further includes: the central cache node receives the third source request sent by the edge cache node, and the third time The source request carries the URL of the resource to be refreshed. When the central cache node determines that the URL of the resource to be refreshed is not in the refresh table and the URL of the resource to be refreshed hits the cache, it sends resource access request response information to the edge cache node, and the resource access request response information Carry resources to be refreshed.

Since the URL of the resource to be refreshed is not recorded in the refresh table, the central cache node has not received a cache refresh request for the URL before determining, and can directly return the resource to be accessed to the client at this time.

In a third aspect, an embodiment of the present invention provides an edge cache node, including: a receiving module for receiving a cache refresh request sent by a control platform, the cache refresh request carrying a uniform resource locator URL of the resource to be refreshed, and a sending module for Send a back-to-origin request to the central cache node, and the back-to-origin request carries the URL of the resource to be refreshed and the refresh time of the resource to be refreshed.

The third aspect or any implementation manner of the third aspect is implemented by the device corresponding to the first aspect or any implementation manner of the first aspect, and the description in the first aspect or any implementation manner of the first aspect is applicable to the third aspect Or any implementation of the third aspect, which will not be repeated here.

In a fourth aspect, an embodiment of the present invention provides a central cache node, including: a receiving module, configured to receive a first back-to-origin request sent by an edge cache node, the first back-to-origin request carrying the URL of the resource to be refreshed and the resource to be refreshed Refresh time, the judgment module, used to confirm that the URL of the resource to be refreshed hits the cache, and the refresh time is later than the cache time of the resource to be refreshed, and the sending module is used to confirm in the judgment module that the URL of the resource to be refreshed hits the cache refresh time later than the cache time In the case of sending a second back-to-origin request to the source site node.

The fourth aspect or any implementation manner of the fourth aspect is implemented by the device corresponding to the second aspect or any implementation manner of the second aspect, and the description in the second aspect or any implementation manner of the second aspect is applicable to the fourth aspect Or any implementation manner of the fourth aspect, which will not be repeated here.

In a fifth aspect, an embodiment of the present invention provides a central cache node, including a memory and a processor, the memory stores program instructions, and the processor runs the program instructions to execute the method in the first aspect or any one of the first aspects. .

In a sixth aspect, an embodiment of the present invention provides an edge cache node, including a memory and a processor, the memory stores program instructions, and the processor runs the program instructions to execute the method in the second aspect or any one of the implementation manners of the second aspect .

In a seventh aspect, an embodiment of the present invention provides a computer-readable storage medium. The computer-readable storage medium stores instructions. When the instructions run on a computer, the computer can execute the first aspect or any one of the first aspects. The method in the way.

In an eighth aspect, an embodiment of the present invention provides a computer-readable storage medium. The computer-readable storage medium stores instructions. When the instructions are run on a computer, the computer executes the second aspect or any one of the implementation manners of the second aspect. Method in.

Description of the drawings

Figure 1 is a system structure diagram of a CDN system according to an embodiment of the present invention;

Figure 2 is a flowchart of a CDN resource refresh method according to an embodiment of the present invention;

Figure 3 is a schematic diagram of a CDN control interface provided by a control platform according to an embodiment of the present invention;

4 is another schematic diagram of a CDN control interface provided by a control platform according to an embodiment of the present invention;

Fig. 5 is another schematic diagram of a CDN control interface provided by a control platform according to an embodiment of the present invention;

Fig. 6 is a flowchart of a cache refresh method of a content distribution network according to an embodiment of the present invention;

Fig. 7 is a flowchart of a back-to-source method in a CDN according to an embodiment of the present invention;

Fig. 8 is another flowchart of a back-to-source method in a CDN according to an embodiment of the present invention;

FIG. 9 is a data interaction diagram of a cache refresh method of a content distribution network according to an embodiment of the present invention;

10 is another data interaction diagram of the cache refresh method of the content distribution network according to the embodiment of the present invention;

11 is a schematic diagram of the device structure of an edge cache node according to an embodiment of the present invention;

FIG. 12 is a schematic diagram of an apparatus structure of a central cache node according to an embodiment of the present invention;

13 is a schematic diagram of another device structure of an edge cache node according to an embodiment of the present invention;

FIG. 14 is a schematic diagram of another device structure of a central cache node according to an embodiment of the present invention.

Detailed ways

First, the terms involved in the embodiments of the present invention are explained as follows:

Source station node: Set the node of the source station as the data source of the content distribution network. This node can be, for example, a server that provides web browsing services. The data cached by the cache node of the content distribution network comes from the source station node. Including resources such as webpages, videos, audios, animations, the origin site node is set with a domain name, and users can access the origin site node or cache node that caches the resources of the origin site according to the domain name. For example, the domain name set for the origin site node is appdl. hicloud.com, the client accesses the origin site by visiting appdl.hicloud.com.

Uniform Resource Locator URL: On the World Wide Web (WWW), each information resource has a unified and unique address on the Internet. This address is called URL. The URL consists of three parts: resource type and resource storage The host domain name, resource file name, and URL have a one-to-one correspondence with the source site's resources.

The general syntax format of URL is:

(The ones with square brackets [] are optional):

protocol://hostname[:port]/path

Format description:

protocol is the protocol, used to specify the transmission protocol used, for example, HTTP protocol, format is HTTP://, or HTTPS://, ftp protocol, format is FTP://, MMS protocol, format is MMS://, ed2k protocol, the format is ed2k://, the most commonly used is the HTTP protocol, which is also the most widely used protocol in the WWW at present, the URL does not display the protocol, which means it is the HTTP protocol.

Hostname is the host name, which refers to the host name, IP address, or domain name of the server that stores the resource, for example, the domain name: appdl.hicloud.com.

port is a port number, an integer, and optional. When omitted, the default port of the scheme is used. Various transmission protocols have default port numbers. For example, the default port of http is 80. If omitted, the default port number will be used. Sometimes for security or other considerations, you can redefine the port on the server, that is, use a non-standard port number. In this case, the port number cannot be omitted from the URL.

path is a path, a string separated by zero or more "/" symbols, generally used to represent a directory or file address on the host. For example, TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node/1.txt, which means the file 1.txt under the directory TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node/.

For example, a complete URL can be expressed as follows:

appdl.hicloud.com/TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node/1.txt

Indicates the file 1.txt in the directory TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node/ in the host with the domain name appdl.hicloud.com.

Optionally, the URL can also be TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node/

Indicates the directory TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node/ in the host with the domain name appdl.hicloud.com

Client: The terminal device used by the user to access the origin site or CDN, such as personal computer, tablet computer, mobile phone, etc.

Content distribution network: includes multiple cache nodes, which cache some or all of the resources of the active station. The multiple cache nodes are specifically edge cache nodes and at least one central cache node. Multiple edge cache nodes are distributed in different regions. The superior node of an edge cache node is a central cache node, and the superior node of the central cache node is the origin node.

Domain Name System (DNS) server: The client only knows the domain name of the origin site node, but in order to enable the client to access the resources of the origin site nearby, when the client sends an access request for the origin site node’s domain name, DNS The server can convert the domain name of the origin site node to the IP address of the edge cache node closest to the client, and return the IP address to the client. The client can directly access the closest edge cache node based on the IP address. The cache node obtains the resource corresponding to the domain name to be accessed. It is worth noting that the access request sent by the client may specifically carry a URL, which includes the domain name of the source site node and the path of the resource to be accessed on the source site node.

Back to the source: As mentioned above, when the edge cache node does not cache the resource corresponding to the URL or confirms that the cached resource is an old resource, it needs to return to the source to the superior central cache node. Specifically, the edge cache node sends back to the central cache node Source request, the central cache node responds to the back-to-origin request, and the central cache node sends back the source response information to the edge cache node when the resource corresponding to the URL is cached. The back-to-origin response information carries the resource corresponding to the URL, and the edge cache node Cache the resource and return it to the client.

Further, when the central cache node does not cache the resource corresponding to the URL or confirms that the cached resource is an old resource, it also needs to return to the source node of the superior. Specifically, the central cache node sends another source to the superior source node. For a back-to-origin request, in response to the back-to-origin request, the higher-level source site node sends another back-to-origin response message to the central cache node when the resource corresponding to the URL is cached locally. , The central cache node caches the resource, and returns the resource to the edge cache node,

Control platform: used to manage the CDN, the control platform has established data connections with each cache node, and provides a CDN control interface. After updating the resources on the source site node, the user can log in to the CDN control interface of the control platform and submit the refresh task to the control The platform enables the control platform to send a cache refresh request for a specific URL to all cache nodes of the CDN. The cache refresh request is used to instruct all cache nodes of the CDN to record that the resource corresponding to the URL has been updated. The control platform can be set on an independent server, or on any cache node, or on a virtual machine, which is not limited in the embodiment of the present invention.

In a possible implementation, the control platform may be, for example, a content management system (Content Management System, CMS). The CMS is used for information management, information publishing, and website maintenance, and is a web interactive content management and publishing application system developed . CMS includes the entire process of information collection, sorting, classification, review, release and management. It has complete information management and release management functions. Users can easily submit the information that needs to be released at any time without having to master complicated technologies.

Caching: In the embodiment of the present invention, caching refers to storing all or part of the source station's resources in the local memory of the edge cache node and the central cache node.

Cache table: The cache table records the URL, cache time, and the storage address of the resource corresponding to the URL in the local memory of the resource that has been cached in the local storage. The cache time is the time point when the cache node caches the resource in the local storage.

Hit cache: refers to the situation where the URL is queried in the cache table. A hit cache indicates that the resource corresponding to the URL is stored in the local storage. When the cache is not hit, it indicates that the resource corresponding to the URL is not stored in the local storage.

Refresh table: The refresh table includes the URL of the resource to be refreshed and the refresh time of the resource to be refreshed.

Resources: including web pages, videos, audios, animations and other data.

Please refer to Figure 1 below. Figure 1 is a system structure diagram of a CDN system according to an embodiment of the present invention. As shown in Figure 1, the CDN system includes an origin node 10, a control platform 20, a content distribution network CDN, and clients 101-105. .

The content delivery network CDN includes central cache nodes 60-61 and edge cache nodes 70-74. It is worth noting that in other embodiments, the number of central cache nodes is not limited to two, and can be other positive integers. Edge cache cache nodes The number of is not limited to 5, it can be other positive integers.

Edge cache nodes are located in different regions. For example, edge cache nodes 70 can be located in South China, edge cache nodes 71 are located in Central China, edge cache nodes 72 are located in West China, and edge cache nodes 73 are located in North China. The edge cache node 74 is located in East China. The upper node of the edge cache node 70-72 is the central cache node 60, the upper node of the edge cache node 73-74 is the central cache node 61, and the upper node of the central cache node 60-61 is the source Station node 10.

For example, client 101 is located in South China, so the distance between client 101 and edge cache node 70 is the closest, client 102 is located in Central China, so client 102 and edge cache node 71 are in the same area, and client 103 is located in West China. Therefore, the client 103 and the edge cache node 72 are in the same area, and the client 104 is located in North China. Therefore, the client 104 and the edge cache node 73 are in the same area. The client 105 is located in East China. Therefore, the client 105 and the edge cache node 74 are located in the same area. In the same area.

It is worth noting that the CDN system also includes a DNS node (not shown in the figure). The DNS node records the correspondence between the client's IP address and the IP address of the edge cache node closest to the client. For example, the client 101 sends a DNS request for the URL of the source site, and the DNS node obtains the IP address of the edge cache node 70 from the above correspondence according to the source IP address carried in the DNS request (that is, the IP address of the client 101), and Return the IP address to the client 101, and the client 101 can send a resource access request carrying the URL of the resource to be accessed to the edge cache node 70. When the edge cache node 70 caches the resource to be accessed, the edge cache node 70 returns to the client 101 Cache the resources to be accessed, so that the client can access the resources to be accessed nearby.

Continuing the above example, if the edge cache node 70 does not cache the resource to be accessed, the central cache node 60 at the higher level sends back the source request. If the central cache node 60 caches the resource corresponding to the URL of the source site, it returns the request to the edge cache node 70 Resources. If the central cache node 60 does not cache the resource corresponding to the URL of the source site, the central cache node 60 sends another source request to the source site.

Based on the CDN system shown in Figure 1, when the user updates the resource corresponding to the specific URL of the origin site at the origin site node 10, for example, updates the picture of a specific webpage, after the origin site updates the resources of the specific URL, if the CDN cache node If the resource corresponding to the specific URL is not updated, the client may receive the old resource before the update from the edge cache node.

In order to solve the above technical problems, in a possible implementation manner, after the user updates the resource corresponding to the specific URL of the origin site at the origin site node 10, the user logs in to the CDN control interface provided by the control platform 20, enters the URL and sends out the target The refresh command of the URL, the URL is the URL of the resource to be refreshed.

The control and control platform 20 first sends a cache refresh request to the central cache node 60-61, where the cache refresh request carries the URL of the resource to be refreshed. The URL of the resource to be refreshed is the specific URL of the source station corresponding to the above-mentioned updated resource. The central cache node 60 -61 After receiving the cache refresh request, it records that the resource to be refreshed has been refreshed at the source site node, and returns the cache update success message to the control platform 20.

After the control platform 20 respectively receives the cache update success information sent by the central cache nodes 70-74, it then sends a cache refresh request to the edge cache nodes 70-74. After the edge cache nodes 60-61 respectively receive the cache refresh request, the record is to be refreshed. The resource has been refreshed at the origin site, and the cache update success information is returned to the control platform 20. After the control platform 20 receives the cache update success information sent by the edge cache nodes 70-74, it confirms that the resources to be refreshed in all cache nodes have been updated. The user is prompted that the resources to be refreshed in the CDN have been successfully updated.

In this possible implementation, after the edge cache node records that the resource to be refreshed has been refreshed at the origin site, when receiving a resource access request for the URL of the resource to be refreshed sent by the client, even if its own cache has the resource to be refreshed , It will not send these resources to the client, but send back the source request to the central cache node.

In the same way, after the central cache node records that the resource to be refreshed has been refreshed at the origin site, when it receives a resource access request for the URL of the resource to be refreshed sent by the edge cache node, it will not send it to the The edge cache node sends the resource to be refreshed, but sends another back-to-origin request to the origin node. The origin node sends the user's updated resource to be refreshed to the central cache node according to the back-to-origin request, and the central cache node caches the resource to be refreshed , And send the resource to be refreshed to the edge cache node, and the edge cache node provides the resource to be refreshed to the client.

Since the control platform first sends a cache refresh request to the central cache node, and after ensuring that the central cache node records that the resource to be refreshed has been updated, it sends a cache refresh request to the edge cache node, thus avoiding the edge cache node from receiving the cache refresh request first If the central cache node receives a cache refresh request, this situation will cause the client to pull old resources from the central cache node.

Specifically, the edge cache node receives the cache refresh request sent by the control platform and records that after the resource to be refreshed has been refreshed at the origin site, if it receives a resource access request for the URL of the resource to be refreshed from the client at this time, Even if the edge cache node caches a resource to be refreshed, it cannot be returned to the client because the resource is a resource before the update. The edge cache node sends a return request for the URL of the resource to be refreshed to the upper-level central cache node. The upper-level central cache node has not yet received the cache refresh request sent by the control platform, and locally caches the resources to be refreshed before the source station is updated. The upper-level central cache node will return the local cache to the edge cache node for the return request. Resources to be refreshed. However, because the higher-level central cache node has not received the cache refresh request sent by the control platform, the locally cached resources to be refreshed are the old resources before the source site is updated, and the edge cache nodes will return the old ones to the client The resource to be refreshed, so that the resource received by the client is not the latest resource after the source station is updated.

Therefore, the control platform first sends a cache refresh request to the central cache node, and after ensuring that the central cache node records that the resource to be refreshed has been updated, it sends a cache refresh request to the edge cache node to ensure that the client pulls from the central cache node. The situation with old resources will not happen. However, since the control platform needs to wait for all central cache nodes to return cache update success information before sending cache refresh requests to edge cache nodes, and wait for all edge cache nodes to return cache update success information before confirming the success of the CDN update, It takes more time and the user experience is not good.

Hereinafter, based on the CDN system shown in FIG. 1, another possible implementation manner of the embodiment of the present invention will be introduced. In this implementation manner, the control platform sends a cache refresh request to all central cache nodes in the CDN and Edge cache nodes can ensure that the client pulls old resources from the central cache node will not happen.

First, please refer to FIG. 2. FIG. 2 is a flowchart of a CDN resource refresh method according to an embodiment of the present invention. The execution body of the method is the control platform 20. As shown in FIG. 2, the method includes the following steps:

Step 111: The control platform 20 obtains the URL of the resource to be refreshed.

For example, please refer to Figure 3. Figure 3 is a schematic diagram of a CDN control interface provided by a control platform according to an embodiment of the present invention. As shown in Figure 3, the CDN control interface provides refresh options, and the user can enter the URL of the resource to be refreshed. , For example, appdl.hicloud.com/TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node/, and click the "click to refresh" option, the control platform 20 can obtain the user input to be refreshed resources from the CDN control interface URL.

among them,

appdl.hicloud.com/TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node/1.txt represents the directory of the origin site appdl.hicloud.com TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node 1.txt in /, you need to refresh all subdirectories and files in this directory.

It is worth noting that the CDN control interface can also provide back-to-source message setting options. The user can choose to set the back-to-source message header. At this time, the interface shown in Figure 4 is shown, which is a control platform according to an embodiment of the present invention. Another schematic diagram of the provided CDN control interface is shown in Figure 4. In this interface, you can set the HyperText Transfer Protocol (HTTP header), and the user can choose to send from the edge cache node to the central cache node. A refresh time is added to the header of the back-to-origin request, and the refresh time is the time point when the edge cache node receives the first cache refresh request (which will be described in detail below).

Step 112: After the user clicks the "click to refresh" option, the control platform 20 may send the first cache refresh request carrying the URL of the resource to be refreshed to the edge cache nodes 70-75 at the same time, and send the URL of the resource to be refreshed The second cache refresh request to the central cache node 60-61.

Step 113: The control platform 20 receives the first cache refresh success message returned by the edge cache nodes 70-75 according to the first cache refresh request, and receives the second cache returned by the central cache node 60-61 according to the second cache refresh request In the case of successful refresh information, it prompts that the resource to be refreshed has been successfully refreshed.

For example, refer to FIG. 5, which is another schematic diagram of the CDN control interface provided by the control platform according to an embodiment of the present invention. FIG. 5 shows the URL of the resource to be refreshed:

appdl.hicloud.com/TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node/ refreshed successfully in CDN.

In other examples, the function of setting back-to-origin packets can also be set in edge cache nodes 70-75 by default. Users do not need to set back-to-origin packet headers on the CDN control interface, and edge cache nodes 70-75 are sending by default Set the refresh time for the return request to the member node of the superior center.

When the control platform 20 sends the first cache refresh request carrying the URL of the resource to be refreshed to the edge cache nodes 70-75, and sends the second cache refresh request carrying the URL of the resource to be refreshed to the central cache node 60-61, there is no need to wait for the edge cache The cache refresh success message of the node can improve the URL refresh speed of the CDN, thereby improving the user experience.

The above URL refresh method is to add refresh time to the header of the back-to-origin request sent by the edge cache node to the central cache node to ensure that the edge cache node will not obtain the old resources from the superior central cache node. The principle will be described in detail.

Please refer to FIG. 6. FIG. 6 is a flowchart of a method for refreshing a cache of a content distribution network according to an embodiment of the present invention. For clarity, the method is executed by the edge cache node 70 in the CDN system shown in FIG. It is noted that other edge cache nodes in the CDN system shown in FIG. 1 can also perform this method.

The method includes the following steps:

Step 201: The edge cache node 70 receives a first cache refresh request sent by the control platform 20, where the first cache refresh request carries the URL of the resource to be refreshed.

Following the above example, the URL of the resource to be refreshed can be, for example:

appdl.hicloud.com/TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node/.

Among them, appdl.hicloud.com is the domain name of the origin node,

TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node/ is a directory of the origin node.

Step 202: The edge cache node 70 records the URL of the resource to be refreshed carried in the first cache refresh request and the refresh time of the URL of the resource to be refreshed, and sends a first cache refresh success message to the control platform 20.

For example, the refresh time of the URL of the resource to be refreshed is the point in time when the edge cache node 70 receives the first cache refresh request.

Specifically, the edge cache node 70 records the URL and refresh time of the resource to be refreshed in a local refresh table.

Wherein, the edge cache node 70 is provided with a refresh table. After the edge cache node 70 receives the first cache refresh request sent by the control platform 20, the edge cache node 70 records the URL of the resource to be refreshed and the refresh time in the refresh table, specifically , Record the URL of the resource to be refreshed and the refresh time can be recorded as an entry in the refresh table.

In the embodiment of the present invention, the edge cache node 70 may delete the URL and refresh time of the resource to be refreshed recorded in the refresh table after a predetermined time. For example, when the resource to be refreshed is a directory, it may be one month later. Delete the entry that records the URL and refresh time of the resource to be refreshed. When the resource to be refreshed is a file, you can delete the URL and refresh time of the resource to be refreshed in the refresh table after 10 seconds, because refreshing the table will occupy storage space and memory The timing deletion mechanism can save the storage space and memory resources of the edge cache node 70.

Further, when the resource to be refreshed is a file, after the edge cache node 70 refreshes the table and records the URL and refresh time of the resource to be refreshed, if the URL of the resource to be refreshed hits the cache, the edge cache node 70 will delete the pending resource in the local storage. Refresh the resource and delete the entry in the cache table where the URL of the resource to be refreshed is located.

In the case that the resource to be refreshed is a directory, after the edge cache node 70 records the URL and refresh time of the resource to be refreshed in the refresh table, if the URL of the resource to be refreshed hits the cache, since the directory may include multiple files, the edge cache node 70 The resource to be refreshed will not be deleted in the local storage, and the entry where the URL of the resource to be refreshed in the cache table is located will not be deleted.

Step 203: The edge cache node 70 receives the resource access request sent by the client 101, the resource access request carries the URL of the resource to be accessed, and the resource access request is used to request the resource to be accessed.

The URL of the resource to be accessed can be, for example:

That is, the resource to be accessed is the file 1.txt in the source site node whose domain name is appdl.hicloud.com is /TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node/.

Step 204: The edge cache node judges whether the URL of the resource to be accessed matches the URL of the resource to be refreshed, if yes, execute step 205, if not, execute step 210.

Specifically, the edge cache node 70 determines that the URL of the resource to be accessed is the same as the URL of the resource to be refreshed, or when it is determined that the URL of the resource to be refreshed is the prefix of the URL of the resource to be accessed, determines the URL of the resource to be accessed and the URL of the resource to be refreshed. The URL of the refresh resource matches.

Following the example above, the URL of the resource to be accessed is:

The URL of the resource to be refreshed is:

appdl.hicloud.com/TIPSMNG_domestic/EMUI3.14159/C00B050MNG/zh-cn/content/00_node/

The URL of the resource to be refreshed is the prefix of the URL of the resource to be accessed. At this time, the URL of the resource to be accessed matches the URL of the resource to be refreshed.

In some other examples, if the URL of the resource to be accessed is:

At this time, the URL of the resource to be accessed is the same as the URL of the resource to be refreshed, and at this time the URL of the resource to be accessed matches the URL of the resource to be refreshed.

Step 205: The edge cache node 70 determines whether the URL of the resource to be accessed hits the cache, if yes, execute step 206, if not, execute step 207.

For example, the edge cache node 70 determines whether the URL of the resource to be accessed is the same as the URL recorded in the local cache table, if they are the same, the cache is hit, and if they are not the same, the cache is not hit.

Step 206: The edge cache node 70 determines whether the first refresh time is later than the latest cache time, if yes, execute step 207, if not, execute step 212.

Wherein, after the edge cache node 70 has repeatedly cached the same URL, multiple cache times corresponding to the same URL are recorded in the cache table. Therefore, in step 206, select among the multiple cache times corresponding to the same URL in the cache table. The cache time closest to the current time is used as the cache time.

In this embodiment, the refresh time is the time point when the edge cache node 70 receives the first cache refresh request, and the cache time is the time point when the edge cache node 70 caches the resource to be accessed in the local memory. If the refresh time is later than the latest The cache time indicates that the resource to be accessed cached to the edge cache node 70 is the old resource before the source station is updated. At this time, step 207 needs to be performed to return to the source to the upper-level central cache node 60. If the first refresh time is not later than the latest The cache time indicates that the resource to be accessed cached to the edge cache node 70 is a new resource after the source station is updated, and the resource is a resource after the source station is refreshed. At this time, step 212 is executed to return the resource to the client 101.

For example, the edge cache node 70 may obtain the refresh time by querying a local refresh table, and obtain the cache time by querying a local cache table.

Step 207: The edge cache node 70 sends a first back-to-origin request to the upper-level central cache node 60. The first back-to-origin request carries the refresh time and the URL of the resource to be refreshed.

For example, the first back-to-origin request is an HTTP message, and the header of the HTTP message is customized with a refresh time type. The refresh time can be reflected in UNIX timestamp, for example: 1562280282, and UNIX timestamp is 1970 The number of seconds that have passed since January 1 of the year.

The refresh time type is, for example, x-refresh-sendtime, and the HTTP packet header carries the following information:

x-refresh-sendtime: 1562280282.

Step 208: The edge cache node 70 receives the back-to-origin request response information sent by the central cache node 60, and the back-to-origin response information carries the URL of the resource to be refreshed and the resource to be refreshed.

The central cache node 60 generates back-to-origin request response information according to the first back-to-origin request.

Step 209: The edge cache node 70 caches the URL of the resource to be refreshed and the resource to be refreshed, and records the cache time.

Specifically, the edge cache node 70 records the URL of the resource to be refreshed, the cache time, and the storage address of the resource to be refreshed in the local memory as an entry in the cache table. It is worth noting that the cache table may record data corresponding to the same URL. There are multiple cache times, so in step 206, the cache time closest to the current time is selected as the cache time.

In the embodiment of the present invention, the edge cache node 70 periodically deletes entries in the cache table.

Step 210: When the edge cache node 70 determines that the URL of the resource to be accessed does not match the URL of the resource to be refreshed, it means that the resource to be accessed has not been refreshed. At this time, the edge cache node 70 executes step 210 to determine the resource to be accessed. Whether the URL hits the cache, if yes, go to step 212 to directly return the resource to be accessed to the client 101. Since the resource is not refreshed, it is a new resource. If not, go to step 211 to return the source to the central cache node 60.

Step 211: The edge cache node 70 sends a second back-to-origin request to the central cache node 60, and the second back-to-origin request carries the URL of the resource to be refreshed.

In this step, because the URL of the resource to be accessed does not match the URL of the resource to be refreshed, it means that the edge cache node 70 has not received the resource cache refresh request for the URL of the resource to be accessed, so the second source request does not need to carry refresh time.

Step 212: The edge cache node 70 sends resource access request response information to the client 101, and the resource access request response information carries the URL of the resource to be accessed and the resource to be accessed.

In the embodiment of the present invention, the edge cache node 70 sends a first back-to-origin request to the central cache node 60 in response to the resource access request. The first back-to-origin request carries the refresh time and the URL of the resource to be refreshed, and the refresh time is the edge cache. The time point when the node 70 receives the cache refresh request. After the central cache node 60 receives the first back-to-origin request, if the URL of the resource to be refreshed hits the cache, it confirms whether the cached resource to be refreshed is old according to the first refresh time. Resources can avoid the situation that the central cache node 60 directly sends old resources to the edge cache node 70 when the URL of the resource to be refreshed hits the cache.

In the embodiment of the present invention, in step 202, after the edge cache node 70 deletes the URL of the resource to be refreshed and the refresh time after refreshing the table after a predetermined time, if the client 101 sends another resource access for the URL of the resource to be refreshed The request is sent to the edge cache node 70. At this time, the edge cache node 70 cannot find the URL of the resource to be refreshed in the refresh table. At this time, the edge cache node 70 sends back to the source after confirming that the URL of the resource to be refreshed hits the cache. The request response information is sent to the central cache node 60, and the return request response information carries the URL of the resource to be refreshed and the cached resource to be refreshed.

In other embodiments of the present invention, the refresh time may also be uniformly set by the console 20 and carried in the first cache refresh request sent by the console 20 to the edge cache node 70. For example, the refresh time can be defined as the time point recorded by the control platform 20 when the user clicks the "click to refresh" button on the CDN control interface in FIG. 3.

Please refer to FIG. 7 below. FIG. 7 is a flowchart of a back-to-origin method in a CDN according to an embodiment of the present invention. For clarity, the method is executed by the central cache node 60 in the CDN system shown in FIG. Note that other central cache nodes shown in Figure 1 can also perform this method.

The method includes the following steps:

Step 401: The central cache node 60 receives the back-to-origin request sent by the edge cache node 70.

Continuing the above example, the back-to-origin request may be the first back-to-origin request that carries the first refresh time and the URL of the resource to be refreshed in step 207 shown in Figure 6, or it may be the URL of the resource to be refreshed in step 211 without carrying it. The second back-to-origin request with the first refresh time.

Step 402: The central cache node 60 judges whether the return-to-origin request carries the first refresh time, if yes, execute step 403, if not, execute step 408.

Continuing the above example, when the return-to-origin request is an HTTP message, it can be detected whether the header of the HTTP message is set with the refresh time type x-refresh-sendtime. If so, confirm that the return-to-origin request carries the refresh time.

Step 403: The central cache node 60 determines whether the second cache refresh request sent by the control platform 20 has been received, if yes, execute step 404, if not, execute step 409.

Specifically, when the central cache node 60 receives the second cache refresh request sent by the control platform 20, it records the URL of the resource to be refreshed and the time point when the central cache node 60 receives the second cache refresh request in the local refresh table. On the other hand, if the central cache node 60 receives the second cache refresh request sent by the control platform 20, the local refresh table is not set. At this time, the refresh table does not record the refresh URL and the central cache node 60 receives the second cache refresh The time of the request.

It is worth noting that, in the embodiment of the present invention, when the central cache node 60 receives the second cache refresh request sent by the control platform 20, it records the URL of the resource to be refreshed and the central cache node 60 received in the local refresh table. After the time point of the second cache refresh request, a cache refresh success message is sent to the control platform 20 to notify the control platform 20 that the central cache node 60 has received the second cache refresh request, and the URL of the resource to be refreshed and the central cache node 60 The time point when the second cache refresh request is received is recorded in the refresh table of the central cache node 60.

In the embodiment of the present invention, the central cache node 60 periodically deletes the URL and refresh time of the resource to be refreshed recorded in the local refresh table. For example, if the resource to be refreshed is a directory, the resource to be refreshed can be deleted one month later. Refresh the URL and refresh time of the resource. When the resource to be refreshed is a file, the URL and refresh time of the resource to be refreshed can be deleted after 10 days. Since refreshing the table will occupy storage space and memory, this timing deletion mechanism can save central cache The storage space and memory resources of the node 60.

Step 404: The central cache node 60 determines whether the URL of the resource to be refreshed carried in the return-to-origin request hits the cache, if yes, execute step 405, if not, execute step 410.

Since step 402 has confirmed that the back-to-origin request carries the first refresh time, the back-to-origin request is the first back-to-origin request shown in FIG. 6, where the URL of the resource to be refreshed carried in the back-to-origin request hits the cache. When it is confirmed that the URL of the resource to be refreshed carried in the first source request hits the cache, the central cache node 60 executes the branch of step 405 to confirm whether to return the cached resource to the edge cache node 70 according to the first refresh time. Refresh resources.

In the case where it is confirmed that the URL of the resource to be refreshed carried in the first return-to-origin request does not hit the cache, the central cache node 60 executes step 410 to directly return to the origin node.

In the embodiment of the present invention, the central cache node 60 may delete the URL and refresh time of the resource to be refreshed recorded in the refresh table after a predetermined time. For example, when the resource to be refreshed is a directory, it may be one month later. Delete the entry that records the URL and refresh time of the resource to be refreshed. When the resource to be refreshed is a file, you can delete the URL and refresh time of the resource to be refreshed in the refresh table after 10 seconds, because refreshing the table will occupy storage space and memory , The timing deletion mechanism can save the storage space and memory resources of the central cache node 60.

Further, in the case that the resource to be refreshed is a file, after the central cache node 60 records the URL and refresh time of the resource to be refreshed in the refresh table, if the URL of the resource to be refreshed hits the cache, the central cache node 60 deletes the resource in the local storage. Refresh the resource and delete the entry in the cache table where the URL of the resource to be refreshed is located.

In the case that the resource to be refreshed is a directory, after the central cache node 60 records the URL and refresh time of the resource to be refreshed in the refresh table, if the URL of the resource to be refreshed hits the cache, since the directory may include multiple files, the central cache node 60 The resource to be refreshed will not be deleted in the local storage, and the entry where the URL of the resource to be refreshed in the cache table is located will not be deleted.

Step 405: The central cache node 60 judges whether the latest refresh time is later than the local cache time, where the latest refresh time is the refresh time carried in the first back-to-origin request and the time point when the central cache node 60 receives the second cache refresh request If it is later, it means that the resource to be refreshed currently cached by the central cache node 60 is the resource before the source site refreshes the resource, that is, the old resource. At this time, the central cache node 60 performs step 410 to return to the source site node. If not, it means that the cached resource to be refreshed is the resource after the source station refreshes the resource, that is, it is a new resource. At this time, step 406 is executed to directly return the cached resource to be refreshed to the edge cache node 70.

Step 406: The central cache node 60 sends the first back-to-origin request response information to the edge cache node 70, and the first back-to-origin request response information carries the URL of the resource to be refreshed and the resource to be refreshed.

Step 407: When the central cache node 60 does not receive the second cache refresh request sent by the control platform 20, step 407 is executed. In step 407, the central cache node 60 determines the status of the resource to be refreshed carried in the first back-to-source request. Whether the URL hits the cache, if yes, execute step 409, if not, execute step 410.

In this step, the back-to-origin request is the first back-to-origin request shown in FIG. 6. When the central cache node 60 determines that the URL of the resource to be refreshed carried in the first back-to-origin request hits the cache, step 409 is executed, and only according to the first The refresh time carried in the return-to-origin request determines whether to send the cached resource to be refreshed to the edge cache node 70.

When the central cache node 60 determines that the URL of the resource to be refreshed carried in the first return-to-origin request does not hit the cache, step 410 is executed to directly return to the origin node.

Step 408: The central cache node 60 judges whether the refresh time carried in the first source request is later than the local cache time, if so, confirms that the cached resource to be refreshed is the old resource before the source station refreshes, and executes step 412 to directly The source site node 10 returns to the source. If not, it is confirmed that the cached resource to be refreshed is a new resource after the source site is refreshed, and step 406 is executed to return the locally cached resource to be refreshed to the edge cache node 70.

Step 409: The central cache node 60 determines whether the second cache refresh request sent by the control platform 20 has been received, if yes, execute step 411, if not, execute step 410.

It is worth noting that in this step, the return-to-origin request is the second return-to-origin request shown in FIG. 6.

Step 410: The central cache node 60 determines whether the URL of the resource to be refreshed carried in the second back-to-origin request hits the cache, if yes, execute step 406 to return the resource to be refreshed to the edge cache node 70, if not, execute step 412 to the source The station node 20 returns to the source.

Step 411: The central cache node 60 judges whether the URL of the resource to be refreshed carried in the return-to-origin request hits the cache, if yes, execute step 406, if not, execute step 412.

Step 412: The central cache node 60 sends another back-to-origin request to the origin node 20, and the back-to-origin request carries the URL of the resource to be refreshed.

Step 413: The central cache node 60 receives the back-to-origin request response information sent by the source site node 20. The back-to-origin request response information carries the URL of the resource to be refreshed and the resource to be refreshed. The central cache node 60 caches the resource to be refreshed in the local storage, and Record the URL of the resource to be refreshed, the cache time, and the storage address of the resource in the cache table.

In the embodiment of the present invention, when the central cache node 60 receives the back-to-origin request carrying the refresh time, even if the URL of the resource to be refreshed carried in the back-to-origin request hits the local cache, the central cache node 60 will refresh according to the refresh time. Time to further confirm whether the resource to be refreshed in its own cache is the resource after the source station is updated. After confirming whether the resource to be refreshed in its own cache is the resource after the source station is updated, the resource is returned to the edge cache node 70. Whether the resource to be refreshed is the resource before the refresh, the source is returned to the origin node 20 to ensure that the client 101 will not obtain the old resource from the edge cache node 70.

It is worth noting that in other embodiments of the present invention, the refresh time can also be uniformly set by the console 20 and carried in the first cache refresh request sent by the console 20 to the edge cache node 70 and the console 20 sent to the central cache. Node 60 is in the second cache refresh request. For example, the refresh time can be defined as the time point recorded by the control platform 20 when the user clicks the "click to refresh" button on the CDN control interface in FIG. 3.

At this time, the edge cache node 70 can perform processing according to the process shown in FIG. 8. FIG. 8 is a flowchart of the back-to-origin method in the CDN according to an embodiment of the present invention. As shown in FIG. 8, the method includes the following steps:

Step 1001: The central cache node 60 receives the back-to-origin request sent by the edge cache node 70.

Step 1002: The central cache node 60 determines whether the return-to-origin request carries a refresh time, if yes, execute step 1003, if not, execute step 1006.

Step 1003: The central cache node 60 determines whether the URL of the resource to be refreshed carried in the return-to-origin request hits the cache, if yes, execute step 1004, if not, execute step 1007.

Step 1004: The central cache node 60 determines whether the refresh time is later than the local cache time, if yes, execute step 1007, if not, execute step 1005.

Step 1005: The central cache node 60 sends first back-to-origin request response information to the edge cache node 70, and the first back-to-origin response information carries the URL of the resource to be refreshed and the resource to be refreshed.

Step 1006: The central cache node 60 determines whether the URL of the resource to be refreshed carried in the return-to-origin request hits the cache, if yes, execute step 1005, if not, execute step 1007.

Step 1007: The central cache node 60 sends another back-to-origin request to the origin node 20, and the back-to-origin request carries the URL of the resource to be refreshed.

Step 1008: The central cache node 60 receives the back-to-origin request response information sent by the source site node 20, and the back-to-origin request response information carries the URL of the resource to be refreshed and the resource to be refreshed, caches the resource to be refreshed in the local storage and in the cache table Record the URL, cache time, and storage address of the resource to be refreshed.

It is worth noting that other central cache nodes shown in Figure 1 can also perform the above methods.

Because in the method shown in FIG. 8, the refresh time is a time point uniformly set by the control platform 20, that is, the refresh time received by the central cache node 60 from the edge cache node 70 is the same as the refresh time it receives from the control platform 20. Therefore, in the method shown in FIG. 8, the central cache node 60 does not need to determine whether the second cache refresh request has been received before. In addition, the steps shown in FIG. 8 are similar to the related steps in FIG. Refer to FIG. 7 for the related description of each step, which is not repeated here.

Similarly, in the embodiment of the present invention, when the central cache node 60 receives the return-to-origin request carrying refresh time, even if the URL of the resource to be refreshed carried in the return-to-origin request hits the local cache, the central cache node 60 will still According to the refresh time, it is further confirmed whether the resource to be refreshed in its own cache is the resource after refresh. After confirming whether the resource to be refreshed in its own cache is the resource after refresh, the resource is returned to the edge cache node 70. Whether the refreshed resource is the resource before refreshing, the source is returned to the source site node 20 to ensure that the client 101 will not obtain the old resource from the edge cache node 70.

In order to further explain the methods shown in FIGS. 2 and 6 to 7, please refer to FIG. 9 below. FIG. 9 is a data interaction diagram of a method for refreshing a cache of a content distribution network according to an embodiment of the present invention. The method shown in FIG. 9 It includes the following steps:

Step 801: The user logs into the origin site node 10, and the resource corresponding to the specific URL of the origin site is updated by the user.

Step 802: The user logs into the CDN control interface and inputs a refresh command for a specific URL, and the control platform 20 receives the refresh command input by the user.

Step 803: The control platform 20 simultaneously sends multiple cache refresh requests to all cache nodes in the CDN.

Specifically, the control platform 20 simultaneously sends multiple first cache refresh requests to all edge cache nodes in the CDN, and sends multiple second cache refresh requests to all central cache nodes in the CDN, the first cache refresh request and the second cache refresh request. The cache refresh request carries the URL of the resource to be refreshed.

Step 804: When receiving the first cache refresh request, the edge cache node 70 records the URL of the resource to be refreshed and the first refresh time to the local refresh table.

Step 805: When the central cache node 60 receives the cache refresh request, it records the URL of the resource to be refreshed and the second refresh time to the local refresh table.

Step 806: After the edge cache node 70 records the URL of the resource to be refreshed and the first refresh time to the local refresh table, it sends the first cache refresh success message to the control platform 20, where the first refresh time is received by the edge cache node 70 The time point of the first cache refresh request.

Step 807: After the central cache node 60 records the URL of the resource to be refreshed and the second refresh time to the local refresh table, it sends the second cache refresh success information to the control platform 20, where the second refresh time is the time received by the central cache node 60 The time point of the second cache refresh request.

Step 808: When receiving the cache refresh success information returned by all cache nodes in the CDN, the control platform 20 prompts the user that the resource to be refreshed has been refreshed in the CDN.

In the embodiment of the present invention, the control platform 20 does not need to send the first cache refresh request to the central cache node first, and sends the second cache refresh request to the edge cache node after confirming that all central cache nodes have returned cache refresh success information. The cache refresh request and the second cache refresh request can be issued at the same time, which can greatly shorten the refresh time.

Step 809: The client 101 sends a resource access request carrying the URL of the resource to be accessed to the edge cache node 70.

Step 810: The edge cache node 70 generates a first back-to-origin request when the preset condition is met.

Among them, the preset conditions are:

The edge cache node 70 is determining that the URL of the resource to be accessed matches the URL of the resource to be refreshed and the URL of the resource to be accessed does not hit the cache; or the edge cache node 70 is determining that the URL of the resource to be accessed matches the URL of the resource to be refreshed, and the URL of the resource to be refreshed The URL of the resource hits the cache, and the refresh time is later than the cache time of the resource to be refreshed.

Step 811: The edge cache node 70 sends the first back-to-origin request to the central cache node 60.

Step 812: When the URL of the resource to be refreshed hits the cache, the central cache node 60 selects the later of the first refresh time and the second refresh time as the latest refresh time, if the latest refresh time is later than the URL of the resource to be refreshed During the cache time of the central cache node 60, a second back-to-origin request is generated.

Step 813: The central cache node 60 sends a second back-to-origin request to the source site node 10.

Step 814: The origin node 10 sends a first response request to the central cache node 60.

Among them, the first response request carries resources to be refreshed.

Step 815: The central cache node 60 caches the to-be-refreshed resource in the local storage, and updates the record cache time 1 to the local cache table.

For example, if the entry 1: the URL of the resource to be refreshed, the cache time 0, and the storage address 1 are recorded before the cache table, the central cache node 60 updates the cache time 0 in this entry 1, and modifies the cache time 0 to the cache Time 1.

Optionally, the central cache node 60 may also add entry 2: URL of the resource to be refreshed, cache time 1, storage address 1, and entry 1 is reserved. When the central cache node 60 searches for the cache time corresponding to the URL of the resource to be refreshed, it obtains entry 1 and entry 2 in the cache table according to the URL of the resource to be refreshed, compares the cache time in entry 1 and entry 2, and selects the later The cache time 2 is used as the cache time of the URL of the resource to be refreshed.

Step 816: The central cache node 60 sends a second response request to the edge cache node 70.

Among them, the first response request carries resources to be refreshed.

Step 817: The edge cache node 70 caches the received resource to be refreshed, records the cache time 2, the URL of the resource to be refreshed, and the storage address of the resource to a local cache table.

The operation of the edge cache node 70 on the local cache table is similar to that of the central cache node 60, which will not be described in detail here.

Step 818: The edge cache node 70 sends a third response request to the client 101.

Among them, the third response request carries resources to be refreshed.

In summary, since the back-to-origin request sent by the edge cache node to the central cache node carries a refresh time, even if the central cache node hits the cache, it will determine whether the resource that hits the cache is a new resource based on the refresh time. Based on this, control The platform 20 can send cache refresh requests to all cache nodes of the CDN at the same time, and there is no need to worry about the central cache node returning old resources to the edge cache nodes. Therefore, the refresh speed of the CDN can be significantly accelerated, thereby improving user experience.

In some cases, for example, the network condition between the central cache node 60 and the control platform 20 is not good, the central cache node 60 will receive the edge cache node 70 without receiving the second cache refresh request sent by the control platform 20 For the sent back-to-origin request, the embodiment of the present invention can ensure that the central cache node 60 will not return the old resources to the edge cache node 70 in this case. The following is an explanation with reference to FIG. 10, which is according to an embodiment of the present invention Another data interaction diagram of the cache refresh method of the content distribution network. The method shown in FIG. 10 includes the following steps:

Step 901: The user logs into the origin site node 10, and the resource corresponding to the specific URL of the origin site is updated by the user.

Step 902: The user logs in to the CDN control interface and inputs a refresh command for a specific URL, and the control platform 20 receives the refresh command input by the user.

Step 903: The control platform 20 simultaneously sends multiple cache refresh requests to all cache nodes in the CDN.

Step 904: When receiving the first cache refresh request, the edge cache node 70 records the URL of the resource to be refreshed and the first refresh time to the local refresh table.

Step 905: After the edge cache node 70 records the URL of the resource to be refreshed and the first refresh time to the local refresh table, it sends the first cache refresh success information to the control platform 20, where the first refresh time is the edge cache node 70 received The time point of the first cache refresh request.

Step 906: The client 101 sends a resource access request carrying the URL of the resource to be accessed to the edge cache node 70.

Step 907: The edge cache node 70 generates a first back-to-origin request when the preset condition is met.

Among them, the preset conditions are:

Step 908: The edge cache node 70 sends the first back-to-origin request to the central cache node 60.

Step 909: If the central cache node 60 confirms that the first refresh time is later than the cache time of the URL of the resource to be refreshed in the central cache node 60 when the URL of the resource to be refreshed hits the cache, a second return request is generated.

Step 910: The central cache node 60 sends a second back-to-origin request to the origin site node 10.

Step 911: The source site node 10 sends a first response request to the central cache node 60.

Among them, the first response request carries resources to be refreshed.

Step 912: The central cache node 60 caches the resources to be refreshed in the local storage, and updates the cache table that records the cache time 1 to the local.

Step 913: The central cache node 60 sends a second response request to the edge cache node 70.

Wherein, the second response request carries resources to be refreshed.

Step 914: The edge cache node 70 caches the received resource to be refreshed, recording the cache time 2, the URL of the resource to be refreshed, and the storage address of the resource to a local cache table.

Step 915: The edge cache node 70 sends a third response request to the client 101.

Among them, the third response request carries resources to be refreshed.

Step 916: When the central cache node 60 receives the cache refresh request, it records the URL of the resource to be refreshed and the second refresh time to the local refresh table.

Step 917: After the central cache node 60 records the URL of the resource to be refreshed and the second refresh time to the local refresh table, it sends a second cache refresh success message to the control platform 20, where the second refresh time is received by the central cache node 60 The time point of the second cache refresh request.

Step 918: When receiving the cache refresh success information returned by all cache nodes in the CDN, the control platform 20 prompts the user that the resource to be refreshed has been refreshed in the CDN.

In summary, since the back-to-origin request sent by the edge cache node to the central cache node carries a refresh time, even if the central cache node hits the cache and has not received the second cache refresh request sent by the control platform, it will determine it based on the refresh time. Whether the resource that hits the cache is a new resource, based on this, the control platform 20 can send a cache refresh request to all cache nodes of the CDN at the same time, without worrying about the central cache node returning old resources to the edge cache node.

Referring to FIG. 11, an embodiment of the present invention further provides an edge cache node 70, which includes a receiving module 701, a sending module 702, a judgment module 703, a recording module 704, and a timing deletion module 704. These modules are used to perform the operations shown in FIG. Related operations in the embodiment.

Referring to FIG. 12, an embodiment of the present invention further provides a central cache node 60, including a receiving module 601, a sending module 602, a judgment module 603, a recording module 604, and a timing deletion module 604. These modules are used to execute FIG. 7 or FIG. 8 shows the related operations in the embodiment.

FIG. 13 is a schematic structural diagram of an edge cache node 70 provided by an embodiment of the present application. The edge cache node 70 includes a processing unit 7000 and a communication interface 7103. The processing unit 7000 is configured to execute functions defined by various software programs, for example, to implement the functions of the edge cache node 70. The communication interface 7103 is used to communicate and interact with other computing nodes, and other devices may be other physical servers. Specifically, the communication interface 7103 may be a network adapter card.

Optionally, the edge cache node 70 may further include an input/output interface 7101, and the input/output interface 7101 is connected to an input/output device for receiving input information and outputting operation results. The input/output interface 7101 may be a mouse, a keyboard, a display, or an optical drive. Optionally, the edge cache node 70 may also include auxiliary storage 7102, which is generally also called external storage. The storage medium of the auxiliary storage 7102 may be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, an optical disk), Or semiconductor media (such as solid state drives) and so on.

Optionally, the edge cache node 70 may further include a bus 7104. Among them, the processing unit 7000, the communication interface 7103, the input/output interface 7101, and the auxiliary memory 7102 may be connected through the bus 7104. The bus 7104 may be a peripheral component interconnect standard (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus 7104 can be divided into an address bus, a data bus, and a control bus. For ease of representation, only one line is used in FIG. 13, but it does not mean that there is only one bus or one type of bus.

The processing unit 7000 may have a variety of specific implementation forms. For example, the processing unit 7000 may include a processor 7002 and a memory 7001, and the processor 7002 performs related operations of the embodiment shown in FIG. 6 according to program instructions stored in the memory 7001. The processor 7002 may be a central processing unit (central processing unit, CPU). The processor can also be other general-purpose processors, digital signal processors (digital signal processors, DSP), application specific integrated circuits (ASICs), ready-made programmable gate arrays (field programmable gate arrays, FPGAs) or other Programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor or the like. Or, the processor 7002 adopts one or more integrated circuits to execute related programs to implement the technical solutions provided in the embodiments of the present application.

The above-mentioned and other operations and/or functions of each unit in the edge cache node 70 are used to implement the corresponding procedures of the methods in FIG. 6, FIG. 9 and FIG. 10, and are not repeated here for brevity.

FIG. 14 is a schematic structural diagram of a central cache node 60 provided by an embodiment of the present application. The central cache node 60 includes a processing unit 6000 and a communication interface 6103. The processing unit 6000 is used to execute functions defined by various software programs, for example, to implement the functions of the central cache node 60. The communication interface 6103 is used to communicate and interact with other computing nodes, and other devices may be other physical servers. Specifically, the communication interface 6103 may be a network adapter card.

Optionally, the central cache node 60 may further include an input/output interface 6101, and the input/output interface 6101 is connected to an input/output device for receiving input information and outputting operation results. The input/output interface 6101 may be a mouse, a keyboard, a display, or an optical drive. Optionally, the central cache node 60 may also include auxiliary storage 6102, which is generally also called external storage. The storage medium of the auxiliary storage 6102 may be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, an optical disk), Or semiconductor media (such as solid state drives) and so on.

Optionally, the central cache node 60 may further include a bus 6104. Among them, the processing unit 6000, the communication interface 6103, the input/output interface 6101, and the auxiliary memory 6102 may be connected through the bus 6104. The bus 6104 may be a peripheral component interconnect standard (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus 6104 can be divided into an address bus, a data bus, and a control bus. For ease of representation, only one line is used for representation in FIG. 14, but it does not mean that there is only one bus or one type of bus.

The processing unit 6000 may have a variety of specific implementation forms. For example, the processing unit 6000 may include a processor 6002 and a memory 6001, and the processor 6002 performs related operations of the embodiment shown in FIG. 7 or FIG. 8 according to program instructions stored in the memory 6001. The processor 6002 may be a central processing unit (central processing unit, CPU). The processor can also be other general-purpose processors, digital signal processors (digital signal processors, DSP), application specific integrated circuits (ASICs), ready-made programmable gate arrays (field programmable gate arrays, FPGAs) or other Programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor or the like. Or the processor 6002 adopts one or more integrated circuits to execute related programs to implement the technical solutions provided in the embodiments of the present application.

The above-mentioned and other operations and/or functions of each unit in the central cache node 60 are used to implement the corresponding procedures of the methods in FIGS. 7 to 10, and are not repeated here for brevity.

It should be noted that the memory in the embodiment of the present application may include a volatile memory (English: volatile memory), such as random-access memory (English: random-access memory, abbreviation: RAM); the memory may also include non-volatile memory. Non-volatile memory (English: non-volatile memory), such as read-only memory (English: read-only memory, abbreviation: ROM), flash memory (English: flash memory), hard disk (English: hard disk drive, abbreviation: HDD) Or a solid-state drive (English: solid-state drive, abbreviation: SSD); the memory may also include a combination of the foregoing types of memory.

Based on the same inventive concept, the present application provides a computer-readable storage medium that stores instructions in the computer-readable storage medium, and when it runs on a computer, the computer executes any possible implementation in the above-mentioned embodiments. The method described.

Based on the same inventive concept, the present application provides a computer program product containing instructions, which when run on a computer, enables the computer to execute the method described in any possible implementation manner in the foregoing embodiments.

Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, this application may adopt the form of a computer program product implemented on one or more computer-usable storage channels (including but not limited to disk storage, optical storage, etc.) containing computer-usable program codes.

This application is described with reference to flowcharts and/or block diagrams of methods, equipment (systems), and computer program products according to the embodiments of this application. It should be understood that each process and/or block in the flowchart and/or block diagram, and the combination of processes and/or blocks in the flowchart and/or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing equipment to generate a machine instruction, so that the instructions executed by the processor of the computer or other programmable data processing equipment are generated A device used to implement the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.

These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing equipment to work in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction device. The device implements the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.

These computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operation steps are executed on the computer or other programmable equipment to produce computer-implemented processing, so as to execute on the computer or other programmable equipment. The instructions provide steps for implementing functions specified in a flow or multiple flows in the flowchart and/or a block or multiple blocks in the block diagram.

Obviously, those skilled in the art can make various changes and modifications to the application without departing from the spirit and scope of the application. In this way, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application also intends to include these modifications and variations.

Claims

A back-to-source method in a content distribution network, characterized in that it includes:

The edge cache node receives a cache refresh request sent by the control platform, where the cache refresh request carries the uniform resource locator URL of the resource to be refreshed;

The edge cache node sends a back-to-origin request to the central cache node, where the back-to-origin request carries the URL of the resource to be refreshed and the refresh time of the resource to be refreshed.
The method according to claim 1, wherein the refresh time is a point in time when the edge cache node receives the cache refresh request.
The method according to claim 1, wherein the refresh time is carried in the cache refresh request, and the refresh time is set by the control platform.
The method according to any one of claims 1 to 3, characterized in that:

Before the edge cache node sends back the source request to the central cache node, the method further includes:

The edge cache node receives the first resource access request sent by the client;

The edge cache node sends back the source request to the central cache node, which specifically includes:

The edge cache node sends the back-to-origin request to the central cache node in response to the first resource access request.
The method according to claim 4, wherein the first resource access request carries the URL of the resource to be accessed, and the edge cache node sends the back-to-origin to the central cache node in response to the resource access request The request includes:

When determining that the URL of the resource to be accessed matches the URL of the resource to be refreshed and the URL of the resource to be accessed does not hit the cache, the edge cache node sends the return request to the central cache node .
The method according to claim 4, wherein the resource access request carries the URL of the resource to be accessed, and the edge cache node sends the back-to-origin request to the central cache node in response to the resource access request, Also includes:

When determining that the URL of the resource to be accessed matches the URL of the resource to be refreshed, the URL of the resource to be accessed hits the cache, and the refresh time is later than the cache time, the edge cache node sends a notification to the The central cache node sends the back-to-origin request, where the cache time is a time point at which the edge cache node caches the resource to be accessed.
The method according to any one of claims 1 to 6, wherein the edge cache node is provided with a refresh table, and after the edge cache node receives the cache refresh request sent by the control platform, the method further comprises:

The edge cache node records the URL of the resource to be refreshed and the refresh time in the refresh table.
The method according to claim 7, wherein after the edge cache node records the URL of the resource to be refreshed and the refresh time in the refresh table, the method further comprises:

The edge cache node deletes the URL of the resource to be refreshed and the refresh time recorded in the refresh table after a predetermined time.
The method according to claim 7, wherein after the edge cache node deletes the URL of the resource to be refreshed and the refresh time recorded in the refresh table after a predetermined time, the method further comprises:

The edge cache node receives a second resource access request sent by the client, where the second resource access request carries the URL of the resource to be accessed;

When the edge cache node determines that the URL of the resource to be accessed is not in the refresh table and the URL of the resource to be accessed hits the cache, the edge cache node sends resource access request response information to the client, The resource access request response information carries the resource to be accessed.
The method according to any one of claims 5 to 9, wherein the edge cache node determines that the URL of the resource to be accessed is the same as the URL of the resource to be refreshed, or determines that the resource to be refreshed If the URL is the prefix of the URL of the resource to be accessed, it is determined that the URL of the resource to be accessed matches the URL of the resource to be refreshed.
A back-to-source method in a content distribution network, characterized in that it includes:

The central cache node receives the first back-to-origin request sent by the edge cache node, where the first back-to-origin request carries the URL of the resource to be refreshed and the refresh time of the resource to be refreshed;

When the URL of the resource to be refreshed hits the cache, the central cache node compares the refresh time with the cache time of the resource to be refreshed, and determines that the refresh time is later than the cache time. In this case, the second back-to-origin request is sent to the source site node.
The method according to claim 11, wherein the refresh time is a point in time when the edge cache node receives the first cache refresh request sent by the control platform.
The method according to claim 11, wherein the refresh time is carried in a cache refresh request received by the edge cache node from a control platform, and the refresh time is set by the control platform.
The method according to claim 11, wherein before the central cache node sends the second back-to-origin request to the source site node, the method further comprises:

The central cache node receives a second cache refresh request sent by the control platform, where the second cache refresh request carries the URL of the resource to be refreshed;

The central cache node determines that the time point when the second cache refresh request is received is later than the cache time.
The method according to any one of claims 11 to 14, wherein the central cache node is provided with a refresh table, and after the central cache node receives the first back-to-origin request sent by the edge cache node, the method further comprises:

The central cache node records the URL of the resource to be refreshed and the refresh time in the refresh table.
The method according to claim 15, wherein after the central cache node records the URL of the resource to be refreshed and the refresh time in the refresh table, the method further comprises:

The central cache node deletes the URL of the resource to be refreshed and the refresh time recorded in the refresh table after a predetermined time.
The method according to claim 16, wherein after the central cache node deletes the URL of the resource to be refreshed and the refresh time recorded in the refresh table after a predetermined time, the method further comprises:

The central cache node receives a third back-to-origin request sent by the edge cache node, where the third back-to-origin request carries the URL of the resource to be refreshed;

When the central cache node determines that the URL of the resource to be refreshed is not in the refresh table and the URL of the resource to be refreshed hits the cache, the central cache node sends resource access request response information to the edge cache node, and the resource access The request response information carries the resource to be refreshed.
An edge cache node is characterized by comprising:

The receiving module is configured to receive a cache refresh request sent by the control platform, where the cache refresh request carries the uniform resource locator URL of the resource to be refreshed;

The sending module is configured to send a back-to-origin request to the central cache node, where the back-to-origin request carries the URL of the resource to be refreshed and the refresh time of the resource to be refreshed.
The edge cache node according to claim 18, wherein the refresh time is a point in time when the edge cache node receives the cache refresh request.
The edge cache node according to claim 18, wherein the refresh time is carried in the cache refresh request, and the refresh time is set by the control platform.
The edge cache node according to any one of claims 18 to 20, wherein:

The receiving module is further configured to receive the first resource access request sent by the client;

The sending module is further configured to send the back-to-origin request to the central cache node in response to the first resource access request.
The edge cache node according to claim 21, wherein the first resource access request carries the URL of the resource to be accessed, and the edge cache node further comprises a judgment module,

The judgment module is configured to determine that the URL of the resource to be accessed matches the URL of the resource to be refreshed and the URL of the resource to be accessed does not hit the cache;

The sending module is configured to send to the central cache node when the judgment module determines that the URL of the resource to be accessed matches the URL of the resource to be refreshed and the URL of the resource to be accessed does not hit the cache Send the return request.
The edge cache node according to claim 21, wherein the resource access request carries a URL of the resource to be accessed, and the edge cache node further comprises a judgment module,

The judgment module is configured to determine that the URL of the resource to be accessed matches the URL of the resource to be refreshed, the URL of the resource to be accessed hits the cache, and the refresh time is later than the cache time;

The sending module is configured to determine in the judgment module that the URL of the resource to be accessed matches the URL of the resource to be refreshed, the URL of the resource to be accessed hits the cache, and the refresh time is later than the cache time In a case, the back-to-origin request is sent to the central cache node, where the cache time is a time point at which the edge cache node caches the resource to be accessed.
The edge cache node according to any one of claims 18 to 23, wherein the edge cache node is provided with a refresh table, the edge cache node further comprises a recording module, and the recording module is used for receiving After the module receives the cache refresh request sent by the control platform, it records the URL of the resource to be refreshed and the refresh time in the refresh table.
The edge cache node according to claim 24, wherein the edge cache node further comprises a timing deletion module, and the timing deletion module is configured to record information of the resource to be refreshed in the refresh table of the recording module. After the URL and the refresh time, delete the URL of the resource to be refreshed and the refresh time recorded in the refresh table after a predetermined time.
The edge cache node of claim 24, wherein:

The receiving module is configured to receive a second resource access request sent by the client, where the second resource access request carries the URL of the resource to be accessed;

The judgment module is configured to determine that the URL of the resource to be accessed is not in the refresh table and the URL of the resource to be accessed hits the cache;

The sending module is configured to send resource access request response information to the client when the judgment module determines that the URL of the resource to be accessed is not in the refresh table and the URL of the resource to be accessed hits the cache , The resource access request response information carries the resource to be accessed.
The edge cache node according to any one of claims 22 to 26, wherein the judgment module determines that the URL of the resource to be accessed is the same as the URL of the resource to be refreshed, or determines that the URL of the resource to be refreshed In the case where the URL of the resource is a prefix of the URL of the resource to be accessed, it is determined that the URL of the resource to be accessed matches the URL of the resource to be refreshed.
A central cache node is characterized by comprising:

A receiving module, configured to receive a first back-to-origin request sent by an edge cache node, the first back-to-origin request carrying the URL of the resource to be refreshed and the refresh time of the resource to be refreshed;

A judging module, configured to confirm that the URL of the resource to be refreshed hits the cache, and the refresh time is later than the cache time of the resource to be refreshed;

The sending module is configured to send the second back-to-origin request to the source site node when the judgment module confirms that the URL of the resource to be refreshed hits the cache and the refresh time is later than the cache time.
The central cache node according to claim 28, wherein the refresh time is a point in time when the edge cache node receives the first cache refresh request sent by the control platform.
The central cache node according to claim 28, wherein the refresh time is carried in a cache refresh request received by the edge cache node from a control platform, and the refresh time is set by the control platform.
The central cache node according to claim 28, wherein:

The receiving module is further configured to receive a second cache refresh request sent by the control platform, where the second cache refresh request carries the URL of the resource to be refreshed;

The judgment module is further configured to judge that the time point when the second cache refresh request is received is later than the cache time.
The central cache node according to any one of claims 28 to 31, wherein the central cache node is provided with a refresh table, and the central cache node further comprises a recording module,

The recording module is configured to record the URL of the resource to be refreshed and the refresh time in the refresh table.
The central cache node according to claim 32, wherein the central cache node further comprises a timing deletion module,

The timing deletion module is configured to delete the URL of the resource to be refreshed and the refresh time recorded in the refresh table after a predetermined time.
The central cache node according to claim 32, wherein:

The receiving module is further configured to receive a third back-to-origin request sent by the edge cache node, where the third back-to-origin request carries the URL of the resource to be refreshed;

The judgment module is further configured to determine that the URL of the resource to be refreshed is not in the refresh table and the URL of the resource to be refreshed hits the cache;

The sending module is further configured to send resource access request response information to the edge when the judgment module determines that the URL of the resource to be refreshed is not in the refresh table and the URL of the resource to be refreshed hits the cache For the cache node, the resource access request response information carries the resource to be refreshed.
A central cache node is characterized by comprising a memory and a processor, the memory stores program instructions, and the processor runs the program instructions to execute the method according to any one of claims 1 to 10.
An edge cache node, comprising a memory and a processor, the memory stores program instructions, and the processor runs the program instructions to execute the method of any one of claims 11 to 17.
A computer-readable storage medium in which instructions are stored, and when the instructions are run on a computer, the computer executes the method according to any one of claims 1 to 10.
A computer-readable storage medium in which instructions are stored, and when the instructions are run on a computer, the computer is caused to execute the method according to any one of claims 11 to 17.