JP2005018398A - Caching system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently cache irrespective of the types of contents for which a web access request is issued. <P>SOLUTION: Even when a content acquired from a web server 13 is regarded as a dynamic content in a caching system 12, in the case where it is designated by a header of HTTP Response that the content can be cached, the content is saved in a cache memory 12a. Thus, in the case where the content, even if being dynamic, is cacheable, the dynamic content can be cached. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a caching system for a web client to acquire content from a web server, and is suitable for application to a mobile communication network.
[0002]
[Prior art]
As for the mobile communication system, the first generation is an analog mobile communication system of the 1980s (NTT system, AMPS (Advanced Mobile Phone Service), TACS (Total Access Communications System), etc.), and the second generation is the 1990s. Digital mobile communication systems (PDC (Personal Digital Cellular Communication System), GSM (Global System for Mobile Communication), IS-54, IS-95, etc.). Furthermore, in the third generation, high speed communication of 64 to 384 kbps at the beginning of the service and 2 Mbps in the future is realized. As a result, the third generation mobile Internet connection service, etc., which was possible in the current second generation mobile communication system, can be used more comfortably and with a large capacity. Various services such as the development of card-type mobile phone terminals, multicall (simultaneous communication of voice and packet), mail with attached files, video applications (streaming, etc.), and videophones can be realized. The spread of such mobile communication systems is remarkable, and in Japan, the number of mobile telephones has reached 60 million. This mobile phone is widely used as a mobile phone, and in the second generation, it is possible to send and receive Internet mail using a mobile phone as a terminal and to acquire web contents from a server on the Internet.
[0003]
[Problems to be solved by the invention]
A caching system is provided between a mobile device in a mobile communication network and a web server that provides content so as to improve response and to effectively use network resources. A general caching system relays a web access request from a web client to a web server, and holds web data obtained from the web server as a cache. When an access request for data already held in the cache is received from the web client, the web access request is not relayed to the web server, and the cached web data is transmitted to the web client. Responding to access requests.
[0004]
By the way, in general, content provided on the web can be classified into the following three types.
1. Static content: content that is not changed after the layout of the web content creator is completed, for example, content that describes a document, a figure, or the like.
2. Dynamic content: content that is partially or wholly generated in response to web access requests. Since the dynamic content is generated every time a web access request is made, the content content is often different. For example, dynamic content is generated in a search site that displays a search result screen when a character to be found is input on an input screen of a web page and a search is executed.
3. Streaming: Unlike static content and dynamic content, streaming is content that is processed in real time while receiving data, rather than being processed after downloading the content requested for web access. For example, real-time audio and video distribution corresponds to streaming.
[0005]
As described above, when the content requested for web access is dynamic content, content with different contents is generated for each request and responded in many cases. Therefore, conventionally, in the case of a web access request for dynamic content, the content is not cached because it may be dynamically generated. Then, there is a problem that the cache cannot be used even in the case of dynamic content in which the same content is generated at all times or for a fixed time. In addition, when the content requested for web access is a part of all the content, there is a risk of data inconsistency when the caching system is used, so the caching system is not used. In these cases, since the caching system relays the web access request to the web server, there arises a problem that the response becomes slow and the processing load of the web server increases.
[0006]
Therefore, an object of the present invention is to provide a caching system that can be used efficiently regardless of the content requested for web access.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a caching system according to the present invention includes a cache memory capable of storing content returned from a web server that can provide content in response to a content request from a web client, and the web When content requested by a client is stored in the cache memory, the corresponding content is read from the cache memory and transmitted to the web client, and the requested content is not stored in the cache memory Includes a control unit that transmits a content request to the web server and transmits the content responded from the web server to the web client. The control unit dynamically transmits the content responded from the web server. Content and Te, if it contains a cacheable instruction information in the response, so that to store the content in the cache memory.
[0008]
In the caching system according to the present invention, the control means further includes, from one of the conditions that the response from the web server to the content request is a normal response, from the web server in response to the content request. The returned content may be stored in the cache memory.
Furthermore, in the caching system according to the present invention, when the content request includes a character indicating that a parameter is added to the content request, the control means receives the content request from the web server. The returned content may be stored in the cache memory.
Furthermore, in the caching system of the present invention, when the path extension included in the content request is a path extension indicating dynamic content, the control unit responds to the content request with the web request. The content returned from the server may be stored in the cache memory.
[0009]
Furthermore, in the caching system according to the present invention, when the path element included in the content request is a path element indicating dynamic content, the control means receives the content request from the web server. The returned content may be stored in the cache memory.
Furthermore, in the caching system of the present invention, when the content returned from the web server is a part of all the content, the control unit does not store the content in the cache memory. You may do it.
Furthermore, in the caching system of the present invention, when the response from the web server includes content cache storage time limit information, the control unit only adds the content to the time limit indicated by the cache storage time limit information. You may make it preserve | save in the said cache memory.
[0010]
Next, another caching system of the present invention that can achieve the above object is a cache that can store content responded from a web server that can provide content in response to a content request from a web client. When the memory and the content requested from the web client are stored in the cache memory, the corresponding content is read from the cache memory and transmitted to the web client, and the requested content is stored in the cache memory. Control means for sending a content request to the web server and sending the content responded from the web server to the web client if not stored, the control means comprising content from the web client Request When the request is for acquiring a part of the content, if the entire content is stored in the cache memory, the content in the corresponding range is read from the cache memory and sent to the web client. I am trying to send it.
[0011]
According to the present invention as described above, when the content acquired from the web server is the dynamic content and the cacheable instruction information is included in the response, the content is stored in the cache memory. As a result, even if the content is dynamic content, the content can be cached. In addition, the caching system can be used even when the content request from the web client is a request for acquiring a part of all content. Accordingly, the caching system can be used effectively, and network resources can be used effectively. As a result, the response to the web access request can be made faster to improve usability, and the processing load on the web server can be reduced.
[0012]
Furthermore, if a normal response is added as a condition to be stored in the cache memory, the reliability of the cache can be improved. In addition, the content request may include a parameter and may include a path extension or a path element indicating dynamic content. Furthermore, when the content acquired from the web server is a part of all the content, the content is not stored in the cache memory so that no data contradiction occurs. Furthermore, when the cache storage expiration information is notified, the caching system can be operated without any trouble even if the dynamic content is updated every predetermined period by caching only the expiration date indicated by the cache storage expiration information. Can be used.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a schematic configuration of a network including a caching system according to an embodiment of the present invention.
The network shown in FIG. 1 is composed of a mobile communication network and other networks such as the Internet. The mobile communication network is shown as a mobile device (MS) 10 that is a mobile phone, for example, and a wireless communication path 11. . Another network is shown as a web server 13 located on the network. The caching system 12 according to the present invention is arranged between the mobile communication network and the web server 13 and relays a web access request from the mobile device 10 to the web server 13 and obtains it from the web server 13 by relaying. The transmitted web data (content) is transmitted to the mobile device 10 and stored in the cache memory 12a provided in the caching system 12. When the mobile device 10 receives a content acquisition request for content already held in the cache memory 12a as a cache, the content acquisition request is not relayed to the web server 13, and the cached content is transferred to the cache memory 12a. Is read out and transmitted to the mobile device 10 to respond to the content acquisition request. Such processing executed by the caching system 12 is referred to as caching system processing. The web server 13 includes a storage unit 14 such as a hard disk in which contents to be provided are stored.
[0014]
Note that HTTP (Hypertext Transfer Protocol) is used as a protocol when the mobile device 10 acquires content from the web server 13. HTTP belongs to the upper layer of TCP / IP (Transmission Control Protocol / Internet Protocol), and is used to transmit / receive HTML documents, images / voices, and other multimedia data between a web server and a web client on the Internet. Communication protocol. HTTP is a very simple protocol including a request (request :: HTTP request) and a response (response: HTTP response), and a request and a response are used as a unit of communication. For example, a web client transmits a URL (Uniform Resource Locators) of an HTML document to be displayed as a request as a request. Receiving this, the web server transmits the HTML document stored by itself specified by the URL to the web client as a response. In HTTP, the connection to the web server is performed every time data is acquired once, and the connection is disconnected when the data reception is completed. The web client is the mobile device 10 in the network shown in FIG.
[0015]
By the way, most of the current web contents including those for the mobile device 10 provided from the web server 13 are very much contents using CGI (Common Gateway Interface). CGI is a mechanism for receiving a request from a web browser, calling a desired external program, and returning the execution result of the program to the web browser. For example, the CGI receives data from the web browser form and returns the result. It is the basic interface for creating applications. For example, a search site that displays a search result screen when a character to be found is input on a web page input screen and a search is executed, or a bulletin board that immediately reflects and displays a character posted by a user on the web uses CGI. Yes. As described above, in the content using the CGI, the content is generated partially or entirely, so that dynamic content is generated.
[0016]
Further, there is ASP (Active Server Pages) as a framework for operating script languages such as Java (TM) Script and VisualBasic (TM) Script on the web server side, and various ActiveX (TM) components. Since the web page described as ASP is first interpreted and executed on the server side, it is possible to provide dynamic content to the client depending on the state at the time of reference. As described above, even content using ASP is generated partially or entirely, so that dynamic content can be generated.
Further, a parameter may be added to the URI (Uniform Resource Identifier) of the HTTP Request. In this case, dynamic content created according to the parameter added as the HTTP Response is returned. The URI is a compact character string specification for specifying a resource on the network, and includes a URL scheme (an identifier of a protocol to be used).
[0017]
In the caching system 12 of the present invention, even if a parameter is added to such dynamic content or HTTP Request using CGI or ASP, it is cached in the cache memory 12a under certain conditions, Caching system processing is performed. It is updated at regular intervals, such as the presence of static content in content that uses CGI or ASP, or when parameters are added to HTTP Requests, and weather forecasts and news dynamic content. This is because dynamic content with the same content may be generated within that time. When parameters are added to such dynamic contents or HTTP requests using CGI or ASP, when the caching system 12 receives an HTTP response from the web server 13 as a cache target, the contents are stored in the cache memory 12a. To save.
[0018]
Here, the caching system 12 relays a web access request (HTTP Request) from the mobile device 10 to the web server 13, and the content obtained from the web server 13 by the relay is transmitted to the mobile device 10 as a web access response (HTTP). FIG. 2 shows a state in which the data is transmitted as (Response) and stored in the cache memory 12 a provided in the caching system 12. The caching system 12 relays the web access request when content corresponding to the web access request is not stored in the cache memory 12a or when the expiration date has passed and the cache hit does not occur. In this case, as shown in FIG. 2, the HTTP request is relayed to the web server 13, and the web server 13 reads or creates content corresponding to the HTTP request from the storage unit 14 and returns it to the caching system 12 as an HTTP response. The caching system 12 transmits the acquired HTTP response to the mobile device 10. In this case, if the content is specified to be cacheable in the HTTP Response header, the content is stored in the cache memory 12a.
[0019]
In this case, even if the content is dynamic content, if the content of the HTTP Request matches the cacheable definition, the corresponding content is stored in the cache memory 12a. Whether or not the dynamic content matches the cacheable definition is determined from the URI in the HTTP request, and the cacheable dynamic content is defined with the URI as a comparison target. That is, when a parameter is added to the URI, a character “?” Is inserted between the URI and the parameter. Therefore, if the HTTP request includes the character “?”, The cache is acceptable. Define. It is also defined as cacheable when the path extension in the URI is “asp” or “cgi”. Further, it is defined as cacheable even when “cgi” is included in the path element in the URI.
[0020]
A chart showing such a definition is shown in FIG. 5 as “Table 1 Cache Control Parameters”. FIG. 4 shows a URI using a URI data structure as an example.
As shown in FIG. 5, in # 1, the character string of the CGI parameter that can be cached is set as “?” As the control parameter cond_cache_char, and all characters in the CGI part are set as comparison targets. In the URI shown in FIG. 4, since the character “?” Is included in the comparison target, it matches the definition content, and the content specified as cacheable in the header in the response from the web server 13 Store in the cache memory 12a.
[0021]
In # 2, the path extension that can be cached is set to “asp: cgi” as the control parameter cond_cache_suffix, and the URI path extension is set as a comparison target. In the URI shown in FIG. 4, the path extension is positioned after “.”. In the URI shown in FIG. 4, the path extension is “cgi” and the path extension to be compared is “cgi”. Those that match the contents and are specified as cacheable in the header in the response from the web server 13 store the contents in the cache memory 12a. Further, in # 3, the path element that can be cached is set as “cgi” as the control parameter cond_cache_comp, and the URI path element is set as a comparison target. In the URI shown in FIG. 4, the path elements are “abc” and “cgi” preceded by “/”, and the path element prefixes are a, ab, abc, e, ef, and efg. Here, if “cgi” is included in the path element to be compared, the contents of the definition match, and those specified as cacheable in the header of the response of the web server 13 store the contents in the cache memory 12a. To store. In addition, if “cgi” is not included in the path element to be compared, it does not match the definition content, so the content is not cached. Even in this case, the definition content of # 1 to # 3 is not cached. If it matches either one, it is cacheable.
[0022]
As described above, content is provided even if a parameter is added to the web access request (HTTP Request) from the mobile device 10 or the path extension is recognized as CGI or ASP or the path element is recognized as CGI. The cacheable designation specified in the Cash-Control header parameter in the HTTP response from the web server 13 is evaluated with priority, and is cached in the cache memory 12a only when there is a cacheable designation. When there is a content acquisition request for the same content, the cache hit content in the cache hit process in the caching system 12 is read from the cache memory 12a and transmitted to the request source. In this case, the caching system 12 does not relay the web access request to the web server 13.
[0023]
The situation in this case is shown in FIG. In FIG. 3, the caching system that has received the HTTP request from the mobile device 10 executes a cache system process and determines whether or not the requested content has a cache hit in the cache hit process. If a cache hit occurs, the content is read from the cache memory 12a and transmitted to the mobile device 10 as an HTTP response.
By the way, when the valid period is specified in the Cash-Control header parameter of the HTTP response from the web server 13, the valid period is cached in the cache memory 12a as the cache storage period. Thereby, even if it uses ASP or CGI, it can respond to a static content and a dynamic content updated for every predetermined period.
[0024]
As described above, in the caching system 12, the content is cached in the cache memory 12a on the condition that it is designated as cacheable in the Cash-Control header parameter in the HTTP response. As a result, even contents that are dynamically generated can be cached for contents that are desired to be cached or contents that have not been cached in the past. The condition for caching the above-mentioned response is compliant with HTTP 1.1. Accordingly, FIG. 6 is a chart showing conditions for caching HTTP1.1 compliant responses. As shown in FIG. 6, the header parameters in the HTTP response include a Date header parameter indicating the date and time of content creation, a Cache-Control header parameter and Expire header parameter that specify a valid period, and a Cache-Control header parameter that specifies cacheable. There is a Last_Modified header parameter indicating the last update date. The Cash-Control header parameter that specifies the valid period includes the max-age parameter and the s-maxage parameter, and the Cache-Control header parameter that specifies cacheable includes the public parameter, no_transform parameter, must # revalidate parameter, and proxy_revalidate. There are parameters.
[0025]
FIG. 6 shows nine patterns 1 to 9 in which these four header parameters are combined, and the Cache-Control header parameters of patterns 2, 4, 6, and 8 are parameters that can be cached. It has become. The cached content is used as valid only for the valid period determined for each content. In patterns 2 and 6, the valid period is specified by the Cashe-Control header parameter. However, in patterns 4 and 8, the effective period of the content is not specified. Therefore, in pattern 4, the last update date specified (Last Modified) is used to calculate (Last Modified-Date value) * 10%, and this calculation result is used as the valid period of the response cache. Further, since the last update date is not specified in the pattern 8, the standard Max-age is set as the valid period of the response cache. As a result, it is possible to determine the cache valid period when the HTTP Response content having the header corresponding to the patterns 2, 4, 6, and 8 is cached in the cache memory 12a.
The cache memory 12a is preferably cached when the status code during the response from the web server 13 indicates a normal response. This is the same when caching static content as well as dynamic content.
[0026]
In addition, when web content is acquired by the mobile device 10 using wireless communication means, the rate of midway disconnection is higher than the rate of midway disconnection in wired communication. When the disconnection occurs in the middle, the mobile device 10 that is acquiring the web content makes a content request of a partial request (Byte-Range request) in order to acquire the rest of the content that could not be acquired. . Conventionally, since a data contradiction may occur for a partial request, the cache function is not used. However, in the caching system 12 of the present invention, it corresponds to the cache memory 12a held in the caching system 12. The caching system processing is performed only when there is all content including the partial content. That is, when the corresponding content is cached, the content in the specified range of all the content is read from the cache memory 12a according to the byte range specification of the partial request, and transmitted to the mobile device 10 as a response. ing. In this case, only when all contents are cached, if all contents are not cached, the contents in the range specified by the byte range do not match the read partial contents, and the request This is because there is a risk of inconsistency between response contents.
[0027]
In addition, for the byte range designation of the read destination by the Range header in the partial request, the caching system process is performed only when only a single range is designated. When a plurality of ranges are specified, the caching system process is not performed, and the partial request is always relayed to the web server 13. The web server 13 transmits a part of the content corresponding to the partial request to the caching system 12 as a response, and the caching system 12 relays the part of the content to the mobile device 10. Thereby, the partial content in the range requested by the mobile device 10 in a partial request (Byte-Range request) is acquired by the mobile device 10. Even if the caching system 12 receives partial content corresponding to the partial request from the web server 13, the partial content is not cached and is not stored in the cache memory 12a.
[0028]
Next, FIG. 7 shows a flowchart of the cache system process executed by the caching system 12 according to the present invention.
The cache system process shown in FIG. 7 is started when an initial process is performed after the caching system 12 is turned on or reset. When the cache system process is started, it is determined whether or not there is a content request from the mobile device 10 in step S1. Here, when there is no content request, it waits here until a content request is detected. If the caching system 12 receives, for example, an HTTP request from the mobile device 10 and determines that there is a content request, the process proceeds to step S2. In step S2, it is determined whether a cache for the URI of the HTTP request exists in the cache memory 12a, and whether or not the valid period of the cached content has expired and is valid.
[0029]
If the cache for the HTTP Request URI exists in the cache memory 12a and the cached content is determined to be valid, the process proceeds to step S3, and whether or not there is a cache unusable instruction in the HTTP Request header. Is judged. If it is determined that there is no cache unavailable instruction in the HTTP request header, the process proceeds to step S4, and it is determined whether the HTTP request is a request for dynamic content that can be cached based on the URI of the HTTP request. . In this determination, whether or not cache is possible is determined by comparing the comparison objects shown in Table 1 shown in FIG. When it is determined that the HTTP request is a request for dynamic content that can be cached, it is determined whether or not the byte range specification (range specification) of the partial request is included in the header of the HTTP request. If it is determined that the HTTP request header includes the byte range designation of the partial request, the process proceeds to step S6 and the partial request cache hit process is executed. In the partial request cache hit process, it is determined that a cache hit has occurred when all contents including the corresponding partial contents exist in the cache memory 12a and the cache is determined to be valid.
[0030]
If it is determined in step S5 that the HTTP request header does not specify the byte range of the partial request, the process proceeds to step S9 and normal cache hit processing is executed. In the normal cache hit process, it is determined that a cache hit has occurred when the corresponding content exists in the cache memory 12a and the cache is determined to be valid. When the process of step S6 or step S9 ends, the process proceeds to step S7 to determine whether or not a cache hit has occurred. If it is determined in step S5 or step S9 that a cache hit has occurred, the corresponding content is read from the cache memory 12a in step S8 and transmitted to the mobile device that requested the content.
[0031]
If it is determined in step S2 that the cache for the HTTP Request URI does not exist in the cache memory 12a or the cached content is not valid even if it exists, the process proceeds to step S10 and the content request is relayed to the web server 13. Is done. If it is determined in step S3 that there is a cache unavailable instruction in the HTTP request header, the process proceeds to step S10 and the content request is relayed to the web server 13. Furthermore, when it is determined in step S4 that the HTTP request is not a request for dynamic content that can be cached, the process proceeds to step S10 and the content request is relayed to the web server 13. Furthermore, when it is determined in step S7 that a cache hit has not occurred, the process proceeds to step S10 and the content request is relayed to the web server 13. When the processing in step S10 is completed, the content acquired from the web server 13 in step S11 is transmitted to the mobile device that requested the content. Next, a caching process to be described later for caching the content acquired in step S12 is performed. When the process of step S8 or step S12 ends, the process returns to step S1 and the process of step S1 to step S12 is repeatedly executed every time a content request is detected.
[0032]
Next, FIG. 8 shows a flowchart of the caching process executed in step S12 of the cache system process.
When the caching process shown in FIG. 8 is started, it is determined in step S20 whether or not the response to the GET request is a normal response. If it is determined that the response is normal, the process proceeds to step S21, and it is determined whether or not the response status code indicates partial content. The normal content normal response status code is “200”, and the partial content normal response status code is “206”. Therefore, if it is determined that the status code is “200”, the process proceeds to step S22, and it is determined whether or not there is an instruction to disable the cache in the HTTP Request header. In this case, if it is determined that there is no cache unavailable instruction in the HTTP Request header, the process proceeds to step S23, and it is determined whether or not there is a cacheable instruction in the HTTP Response header from the web server 13. This determination is made by looking at the Cache-Control header parameter for designating cacheability shown in Table 2 shown in FIG.
[0033]
If it is determined that there is a cacheable instruction in the header of the HTTP response, the process proceeds to step S24, where it is determined whether the HTTP request is a request for dynamic content that can be cached. This determination is made by comparing the comparison target shown in Table 1 shown in FIG. 5 in the HTTP Request URI to determine whether or not the dynamic content can be cached. If it is determined that the HTTP request is a request for dynamic content that can be cached, the process proceeds to step S25, and a dynamic content cache determination process is performed. In this dynamic content cache determination process, it is determined whether or not cache is possible from the four header parameters in the HTTP Response shown in Table 2 shown in FIG. Here, for an HTTP response having a header parameter that matches the patterns 2, 4, 6, and 8 shown in Table 2, the content is determined to be cacheable. If it is determined in step S24 that the HTTP request is not a cacheable dynamic content request, the process proceeds to step S26 to perform a normal content cache determination process. Also in this normal content cache determination process, it is determined whether or not the cache is possible from the four header parameters in the HTTP Response shown in Table 2 shown in FIG. Here, for an HTTP response having a header parameter that matches the patterns 2, 3, 4, 6, 7, and 8 in which “O” is added to the response cache column shown in Table 2, the content can be cached. judge.
[0034]
When the process of step S25 or step S26 ends, the process proceeds to step S27, and it is determined whether or not the content acquired from the web server 13 can be cached. If it is determined in step S25 or step S26 that cache is possible, the process proceeds to step S28 and the acquired content is stored in the cache memory 12a. Next, the process returns to the cache system process. If it is not determined that the response is normal in step S20, or if the status code is not determined to be "200" in step S21, it is determined in step S22 that there is a cache unavailable instruction in the HTTP request header. If it is determined in step S23 that there is no cacheable instruction in the header of the HTTP response, and if it is determined in step S27 that caching is not possible, the process returns to the cache system processing and is acquired. Content is not cached.
[0035]
In the above description, the caching system 12 in the case where the mobile device 10 in the mobile communication network acquires content from the web server 13 has been described. However, the caching system 12 of the present invention is not limited to this and is generally applied to HTTP communication. Can do.
[0036]
【The invention's effect】
As described above, according to the present invention, when content acquired from a web server is dynamic content and cacheable instruction information is included in the response, the content is stored in the cache memory. As a result, even if the content is dynamic content, the content can be cached. In addition, the caching system can be used even when the content request from the web client is a request for acquiring a part of all content. Accordingly, the caching system can be used effectively, and network resources can be used effectively. As a result, the response to the web access request can be made faster to improve usability, and the processing load on the web server can be reduced.
[0037]
Furthermore, if a normal response is added as a condition to be stored in the cache memory, the reliability of the cache can be improved. In addition, it is also possible to use a condition that a parameter is added to the content request and a path extension or path element indicating dynamic content is included. Furthermore, when the content acquired from the web server is a part of all the content, the content is not stored in the cache memory so that no data contradiction occurs. Furthermore, when the cache storage deadline information is notified, even if the dynamic content is updated every predetermined period by caching only the deadline indicated by the cache storage deadline information, the caching system can be operated without any trouble. Can be used.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a schematic configuration of a network including a caching system according to an embodiment of this invention.
FIG. 2 is a diagram illustrating a state in which a content request is relayed and acquired content is cached in the network illustrated in FIG. 1;
FIG. 3 is a diagram showing a state when a cache hit occurs in the network shown in FIG. 1;
FIG. 4 is a diagram for explaining a data structure of a URI.
FIG. 5 is a chart showing definitions of cache control parameters in the caching system according to the embodiment of the present invention.
FIG. 6 is a chart showing conditions for caching a response complying with HTTP 1.1.
FIG. 7 is a flowchart of cache system processing executed by the caching system according to the embodiment of this invention.
FIG. 8 is a flowchart of the caching process in the cache system process executed by the caching system according to the embodiment of this invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Mobile device, 11 Wireless communication channel, 12 Caching system, 12a Cache memory, 13 Web server, 14 Storage means

Claims (8)

In response to a content request from a web client, a cache memory capable of storing content responded from a web server that can provide the content;
When the content requested from the web client is stored in the cache memory, the corresponding content is read from the cache memory and transmitted to the web client, and the requested content is stored in the cache memory. If not, a control means for transmitting a content request to the web server and transmitting the content responded from the web server to the web client,
When the content responded from the web server is dynamic content, and the cacheable instruction information is included in the response, the control means stores the content in the cache memory. Caching system characterized by The control means further saves the content returned from the web server in response to the content request in the cache memory on the condition that the response from the web server to the content request is a normal response. The caching system according to claim 1, wherein: When the content request includes a character indicating that a parameter is added to the content request, the control means stores the content returned from the web server in response to the content request in the cache memory. The caching system according to claim 2, wherein: When the path extension included in the content request is a path extension indicating dynamic content, the control means stores the content returned from the web server in response to the content request in the cache memory. 3. The caching system according to claim 2, wherein the caching system is stored. When the path element included in the content request is a path element indicating dynamic content, the control unit stores the content returned from the web server in response to the content request in the cache memory. The caching system according to claim 2, which is configured as described above. 3. The control unit according to claim 2, wherein when the content returned from the web server is a part of all the content, the content is not stored in the cache memory. The described caching system. When the response from the web server includes content cache storage time limit information, the control means stores the content in the cache memory only for the time limit indicated by the cache storage time limit information. 3. A caching system according to claim 2, wherein: In response to a content request from a web client, a cache memory capable of storing content responded from a web server that can provide the content;
When the content requested from the web client is stored in the cache memory, the corresponding content is read from the cache memory and transmitted to the web client, and the requested content is stored in the cache memory. If not, a control means for transmitting a content request to the web server and transmitting the content responded from the web server to the web client,
When the content request from the web client is a request to acquire a part of all the content, the control means, when the entire content is stored in the cache memory, A caching system, wherein content in a corresponding range is read from a cache memory and transmitted to the web client.

Images