JP2003036198A - Cache controlling method of proxy server by white list - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cache controlling method capable of improving cash efficiency regardless of a time zone by synchronizing a cache state in a proxy server with the using state of a client. SOLUTION: In the cache controlling method in the proxy server for repeating data between at least one client connected to a communication network and a data server connected to a communication network except for the above communication network, it is judged whether URL requested by the user of the client is registered in a white list, and data in the URL is processed as a cache object when the URL is registered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of caching data in a server that relays data, and more particularly to a cache control method capable of synchronizing the usage status of a client with the cache status.

[0002]

2. Description of the Related Art Conventionally, as a server for relaying access to the Internet, there is a server having a data cache function. A so-called cache server stores a copy of data managed by a server such as a web server and provides the data promptly on behalf of the server accessed by the user. For example, in a proxy server that is connected between a LAN (local area network) in an organization such as a company and a communication network such as the Internet, a web page referenced by someone in the organization is stored for a certain period of time. Every
When another user accesses the same page, the web page on the cache server is sent.

In a server having a cache function as described above, conventionally, all data is cached, and when the maximum size of the cache area of the storage medium is exceeded, subsequent data is unconditionally overwritten. Therefore, the overwritten data is unconditionally overwritten with another data. The same applies to the cache method using the index, and the data to be cached is
Since all the data to be relayed are subject to rewriting, if the data has different contents but the same index, it will be unconditionally rewritten to different data.

[0004]

As described above, in a cache server such as a proxy server that relays data, all data is processed as a cache target, so that the cache area has a low utilization rate. There was a problem that it would be occupied by, or the data would be overwritten when there was no space. In addition, in the cache method using the hit rate, the cache efficiency is improved, but the hit rate varies on the time axis, so the cache efficiency depends on the time zone and the access frequency of the same data. There was a problem to say.

The present invention has been made under the circumstances as described above, and an object of the present invention is to synchronize the cache status in the proxy server with the usage status of the client, and to relate to the time zone. It is to provide a cache control method that can improve the cache efficiency without the need.

[0006]

According to the present invention, a cache in a proxy server for relaying data between one or more clients connected to a communication network and a data server connected to a communication network other than the communication network. The present invention relates to a control method, and the object of the present invention is to determine whether a URL requested by a user of the client is registered in a white list, and if the URL is registered, the UR
This is achieved by processing L data as a cache target.

Further, the white list is a list in which useful URLs that are frequently used by individual users or specific groups who use the client are registered, and the white list is a list managed by a web browser and a specific purpose. The dedicated software used includes one or both of the lists managed by the dedicated software; the white list is provided on the client side, and the client side performs the determination and indicates whether the cache is necessary or not.
D is set in an HTTP request and transmitted, and the proxy server controls whether or not to cache the data by identifying whether or not to be cached by the cache ID set in the HTTP request; Stored in the storage medium of the proxy server side,
The proxy server makes the determination to control the cache of the data; the communication network to which the client is connected is a LAN or an intranet to which the data server is connected, and the communication to which the data server is connected The network is a LAN, an intranet, or the Internet;

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As a method of accessing a website on the Internet, it is troublesome to input an address each time, so a URL (Un
iform Resource Locators) and useful URLs for browser menu lists, such as Microsoft Inte
It is generally used to register to "Favorites" of rnet Explorer or "Bookmarks" of Netscape Navigator of Netscape Communications and access the page by selecting URL from the menu list. . In addition, recently, it supports the browsing of useful data and the transfer of data by using communication networks such as LAN and the Internet for specific groups such as support software for teaching students at schools and medical information networks. Many dedicated software have been developed and are being realized. In such dedicated software for a specific purpose, for example, a list in which URLs of specific parties are registered is used to access the corresponding data server, deliver useful data to the corresponding clients, or There is proposed a device having a function for facilitating a conversation by exchanging data between clients.

In the present invention, useful URLs often used by individual users or specific groups such as the menu list for browsers and the list of dedicated software as described above.
Lists registered with or managed by dedicated software used for specific purposes (hereinafter referred to as "white list")
Is used for controlling the cache, it is possible to synchronize the cache status of the proxy server with the usage status of the client. That is, according to the present invention, as a criterion for caching data,
In addition to the conventional method, by using a whitelist, the useful data frequently used by each individual user or a specific group is targeted as a cache to improve the hit rate, and the cache area is used only by a specific individual. It is designed to avoid being occupied by data and running out of cache area capacity. In a preferred embodiment of the present invention, a cache control function is incorporated by a plug-in (add-in software) to cooperate with the above-mentioned browser or dedicated software, and an access request for a URL registered in the whitelist is made. In that case, the data is automatically cached.

A preferred embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of the overall configuration of a proxy server system according to the present invention. If you want to connect to the Internet from multiple clients,
For example, as shown in FIG. 1, each client 10 is connected to a LAN 1 such as Ethernet (registered trademark),
Proxy server 2 between LAN 1 and Internet 2
0 is connected and data is transferred between the data server 30 such as a web server and each client 10 via the proxy server 20 having a security function and a cache function. In the present embodiment, a useful URL that is frequently used by individual users or specific groups
The "white list" 3 registered by the client 10
In each case, the proxy server 20 that relays the data controls the data of the URL registered in the whitelist 3 as a cache target. The computer network to which each client 10 is connected is, for example, a corporate network, a home network, a network connecting a teacher's personal computer with each student, a medical information network, or a LAN or an intranet for a specific group of clients. Since the same URL is frequently used in the communication network, the whitelist can be more effectively used for cache control.

FIG. 2 shows an example of an interface related to cache control between the client 10 and the proxy server 20. Whitelist 3 client 1
In the case of a system configuration having 0 side, a setting area of an identifier (hereinafter, referred to as a cache ID) for identifying whether or not to perform the cache is provided in, for example, the header part of the communication protocol, and whether the cache is required or not depends on the cache ID The interface is used to notify the proxy server 20 of the unnecessary. For example, the communication protocol is HTTP (Hypertext Tra
nsfer Protocol), a cache ID setting area is provided in the extension header part of the HTTP protocol header.
Then, the client 10 side is provided with a cache ID setting function of setting the cache ID in the relevant area of the extension header part by referring to the white list 3, and the HTTP request in which the cache ID is set is sent from the client 10 side to the proxy server 20 side. By transmitting the URL, the proxy server 20 is instructed whether to cache the data of the URL.

The above-mentioned cache ID setting function is performed by the HT.
It is realized by incorporating the TP request into the software (the above-mentioned browser or dedicated software) by, for example, a plug-in (add-in software). On the other hand, the proxy server 20 side determines whether to cache the data of the access URL based on the cache ID of the header part of the communication protocol, and if the cache ID is set, the data of the URL is cached. And a step of processing as. These steps (functions) on the proxy server 20 side are realized by incorporating them in a cache control unit that controls cache of data.

An operation example of the proxy server system to which the cache control method based on the white list according to the present invention is applied in the above-mentioned configuration will be described with reference to the flowchart of FIG. Note that the cache control of the proxy server after it is determined to be the cache target is equivalent to the conventional control method using the hit rate, the update date / time, the storage time on the cache, the data size, the type of the cache medium, etc. The description is omitted here.

When the URL of the access destination (hereinafter referred to as "access URL") is designated by the user or the dedicated software, the client 10 accesses the access UR.
It is determined whether L is registered in the white list (step S1). Then, when registered in the white list, a cache ID indicating that caching is performed (or cache required / not required) is set in the protocol header part of the HTTP request, and an access request for data acquisition (HTTP request and access URL) is set. ) Is transmitted (step S2). The proxy server 20 that has received the access request checks whether or not there is a cache ID in the protocol header of the HTTP request (steps S3 and S4). If there is a cache ID, the access URL data is in the cache. It is determined whether or not (step S5).

If there is access URL data in the cache, the data is acquired from the cache (step S6) and sent to the requesting client 10 (step S7). On the other hand, in step S5,
If there is no access URL data in the cache,
A flag indicating that the data is to be cached is set (step S8), and the access URL data is acquired from the Internet (step S9). In step S4, if there is no cache ID in the protocol header, the process proceeds to step S9 and the access URL data is acquired from the Internet. Subsequently, it is determined whether or not the cache target flag is set (step S10). If the flag is not set, the process proceeds to step S7, and the data acquired from the Internet is sent to the requesting client 10. After transmitting, the processing for the acquisition request of the data is completed.

On the other hand, if the data cache flag is set in step S10, that is, if the cache ID is present in the access request and there is no access URL on the cache, the data acquired from the Internet is stored in the memory. Write to the cache storage medium 21 such as a disk medium (step S11), the process proceeds to step S6, the data of the access URL is acquired from the cache, the data is transmitted to the client 10 of the request source, and Finish the process for the acquisition request.

Next, another embodiment of the cache control method based on the white list will be described.

In the above-described embodiment, the case where the white list is provided on the client side has been described as an example.
The white list may be provided on the proxy server side. In addition, if the access URL is registered in any of the whitelists, the cache target may be provided for both the client side and the proxy server side. Further, URLs registered in the white list may be selectively cached by the user's designation. When applied to a client server system in an organization such as a school or a company, it is preferable that the whitelist is provided as shared data of each client rather than being provided for each client and managed for each client. However, even if the server has a whitelist as shared data,
The white list does not have to be one, and may be prepared and registered for each use or group such as a department.

A method of controlling the data cache by providing a white list on the proxy server side and referring to the white list will be described below.

In the above-mentioned embodiment, that is, the white list is provided on the client 10 side, the client 10 sets the cache ID in the header part of the communication protocol and determines whether the cache is necessary or not according to the cache ID. However, in the mode in which the white list is provided on the proxy server 20 side,
It is not necessary to add a special function to software such as a browser on the client 10 side, and commercially available software can be used as it is. Hereinafter, an operation example on the proxy server 20 side will be described. Note that the control of the cache is the same as the processing of steps S5 to S11 of FIG.

The proxy server that receives the access request from the client side determines whether or not the URL (address of the access destination) is registered in the white list. Only this determination process is added to the proxy server, and the subsequent processes are the same as those in the above-described embodiment. That is, if the access URL is registered in the white list, the data of the URL is cached and the cache is controlled. If it is not registered in the white list, the data of the access URL is acquired from the Internet. Send data to the requesting client. As described above, the why list may be provided on the proxy server side to control the cache of the data of the URL.

In the above-described embodiment, the proxy server is used as an example of the server to which the cache control method according to the present invention is applied. However, the server is not limited to the proxy server and may be a gateway server or a node (Nod).
A server for relaying data between one or more clients connected to a communication network and a data server connected to a communication network other than the communication network, such as a computer for e). The request-destination data server is not limited to a web server on the Internet, and may be a data server connected to a communication network (LAN, intranet, extranet, etc.) other than the Internet.

[0024]

According to the present invention, a whitelist in which useful URLs frequently used by individual users of a client or a specific group are registered is referred to, and URLs registered in the whitelist are referred to. Since it is processed as a cache target, it is possible to synchronize the cache status with the usage status of the client. Therefore, it is possible to improve the cache efficiency regardless of the time zone, and it is possible to reduce the possibility that the cache area is occupied by the data having a low utilization rate and the data is overwritten due to the lack of the space.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of the overall configuration of a proxy server system according to the present invention.

FIG. 2 is a diagram illustrating an example of an interface between a client and a proxy server.

FIG. 3 is a flowchart illustrating a cache control method using a whitelist according to the present invention.

[Explanation of symbols]

1 LAN 2 Internet 3 White list 10 clients 20 proxy server 21 Storage medium for cache 30 data server

Claims (5)

[Claims] 1. A cache control method in a proxy server for relaying data between one or more clients connected to a communication network and a data server connected to a communication network other than the communication network, the client comprising: It is determined whether or not the URL requested by the user of the URL is registered in the white list, and if the URL is registered, the data of the URL is processed as a cache target. Proxy server cache control method by list. 2. The UR in which the white list is often used by the user himself / herself in a URL useful for the user.
L is a list registered or managed by dedicated software used for a specific purpose but managed by a web browser or a list managed by dedicated software used for a specific purpose. The proxy control cache control method according to claim 1, wherein one or both of them are included. 3. The whitelist is provided on the client side, and the client side makes the determination and a cache ID indicating whether a cache is necessary or not is HTTP.
Set in the request and send, the proxy server,
3. The cache control method for a proxy server by a whitelist according to claim 1, wherein whether or not the data is to be cached is identified by the cache ID set in the HTTP request, and the cache of the data is controlled. . 4. The white according to claim 1, wherein the white list is stored in a storage medium on the proxy server side, and the proxy server controls the cache of the data by making the determination. Proxy server cache control method by list. 5. The communication network to which the client is connected is a LAN or an intranet to which the data server is connected, and the communication network to which the data server is connected is a LAN, an intranet or the Internet. 5. A cache control method for a proxy server according to any one of 1 to 4 above.