JP2013178676A - Control system and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a time for transfer of Web pages.SOLUTION: A control system controls transmission/reception of a Web page including a host file and an object file. A transmission part of a server embeds identification information for uniquely identifying the object file by an edition unit for every update in the host file and transmits the identification information. An identification information storage part of a client stores identification information corresponding to the object file of a prescribed edition stored in a cache. A determination part compares identification information taken out of the host file received from the server with identification information stored in the identification information storage part and determines whether or not the object file of an edition that is identified according to the identification information taken out of the host file is stored in the cache. A request part requests the server to transmit the object file when it is determined that the object file is not stored in the cache.

Description

  Embodiments described herein relate generally to a control system and a control method.

  In recent years, with the development of cloud computing, there are increasing cases of web browsing from a smart phone via a wireless line and web browsing of an overseas site via an international line. However, when such a wireless line or an international line is used, it takes time to transfer the Web page, which may affect the quality of experience of the end user.

  For this reason, a Web system that uses HTTP (Hypertext Transfer Protocol) attempts to improve response time when reloading or moving within the same site, such as by a configuration having a cache function on the client side.

R. Fielding, et al., “Hypertext Transfer Protocol-HTTP / 1.1”, [online], [searched February 20, 2012], Internet <URL: http://www.w3.org/Protocols/rfc2616 /rfc2616.html> R. Fielding, et al., “HTTP / 1.1, part 6: Caching”, IETF, [online], [searched February 20, 2012], Internet <URL: http://tools.ietf.org/ html / draft-ietf-httpbis-p6-cache-18>

  However, in the conventional technology described above, it may still take time to transfer the Web page.

  The control system according to the embodiment controls transmission / reception of a Web page including an upper file and an object file whose acquisition destination is described in the upper file. The server includes a transmission unit. The transmission unit embeds identification information for uniquely identifying the object file for each version for each update in the upper file, and transmits the upper file to a client that requests transmission of the Web page. The client includes a cache, an identification information storage unit, a determination unit, and a request unit. The cache stores a predetermined version of the object file received from the server. The identification information storage unit stores the identification information corresponding to a predetermined version of the object file stored in the cache. When the determination unit receives the upper file from the server, the determination unit extracts the identification information from the upper file, compares the extracted identification information with the identification information stored in the identification information storage unit, and It is determined whether or not the version of the object file identified by the identification information extracted from is already stored in the cache. When it is determined that the object file has not been stored in the cache, the request unit requests the server to transmit the object file using the acquisition destination described in the upper file.

  According to the control system and the control method according to the embodiment, there is an effect that the transfer time of the Web page can be shortened.

FIG. 1 is a diagram showing a configuration of a Web system according to the present embodiment. FIG. 2 is a diagram for explaining an HTML (HyperText Markup Language) file according to the present embodiment. FIG. 3 is a diagram for explaining the cache control information according to the present embodiment. FIG. 4 is a diagram for explaining an HTML file according to the present embodiment. FIG. 5 is a diagram for explaining cache determination in the present embodiment. FIG. 6 is a diagram illustrating a computer that executes a program that implements the same function as the Web server or Web client according to the present embodiment.

  Hereinafter, a control system and a control method according to the embodiment will be described. In addition, this invention is not limited by the following embodiment.

  FIG. 1 is a diagram illustrating a configuration of a Web system 10 (also referred to as “control system”) according to the present embodiment. As shown in FIG. 1, the web system 10 includes a web server 100 and a web client 200. The Web server 100 includes an HTML file analysis unit 110, a cache control information embedding unit 120, an HTML file response unit 130, and an object file response unit 140. The Web client 200 also includes a cache 210, a cache control information storage unit 220, an HTML file request unit 230, a cache control information extraction unit 240, a cache determination unit 250, and an object file request unit 260.

  In the present embodiment, the Web page includes an HTML file and an object file whose acquisition destination is described in the HTML file, and has a hierarchical structure in which the upper HTML file and the lower object file have a dependency relationship. Yes. For this reason, the Web client 200 first acquires an HTML file from the Web server 100 and then acquires an object file from the Web server 100 using an acquisition destination described in the HTML file, thereby acquiring a Web page. The Web client 200 also stores a predetermined version of the object file acquired from the Web server in the cache 210. Further, the Web client 200 stores cache control information corresponding to a predetermined version of the object file stored in the cache 210 in the cache control information storage unit 220. The cache control information will be described later.

  Under such a configuration, in the present embodiment, the Web client 200 determines whether or not the object file stored in the cache 210 is the latest object file, thereby reducing the transfer time of the Web page. .

  That is, in the conventional Web system, the Web client inquires the Web server one by one as to whether or not the object file stored in the Web client cache is the latest object file. When the Web server determines each inquiry and determines that the inquiry is not the latest object file, the latest object file is transmitted to the Web client. In this case, inquiries from the Web client to the Web server (one inquiry is about 0.2 KB, for example) are generated in large quantities and individually for the number of objects whose acquisition destinations are described in the HTML file. This large number of individually generated inquiries are transmitted to the Web server via a network with a large delay, such as a wireless line or an overseas line, and it is also possible to determine each inquiry on the Web server side to transfer the Web page. This is thought to be the cause of lengthening

  In this regard, the Web system 10 according to the present embodiment collectively determines whether or not the object file is the latest object file, and requests only the necessary object file from the Web server 100 side. As a result, inquiries that have been generated in large quantities and individually are greatly reduced, and it is possible to shorten the transfer time of the Web page.

  The first download of the web page will be described. First, the HTML file request unit 230 of the Web client 200 transmits a Web page request to the Web server 100. For example, the HTML file request unit 230 receives an input of a URL (Uniform Resource Locator) “http://www.ntt.co.jp/index.html” to the Web browser, and uses the received URL to the Web server 100. to access.

  On the other hand, when the HTML file analysis unit 110 of the Web server 100 receives a request from the Web client 200, the HTML file analysis unit 110 analyzes the requested HTML file and specifies an object file in which an acquisition destination is described in the HTML file.

  FIG. 2 is a diagram for explaining an HTML file according to the present embodiment. For example, there is a description of the href attribute such as “href =” ./ css / 2011 / import_common.css ”in the line indicated by the arrow a in FIG. 2, and this description indicates the object file and its acquisition destination. Similarly, for example, there is a description of the src attribute such as “src =” ./ js / 2011 / import_lib.jis ”in the line of the arrow b in FIG. 2, and this description also indicates the object file and the acquisition destination thereof. . For example, the HTML file analysis unit 110 analyzes the HTML file “index.html” and specifies an object file described in such an href attribute or src attribute.

  Subsequently, the cache control information embedding unit 120 generates cache control information for each object file specified by the HTML file analysis unit 110, and embeds the generated cache control information in the HTML file. Here, the cache control information is identification information for uniquely identifying each object file for each version for each update. For example, the cache control information is random number information (e.g., information such as Etag) assigned every time the object file is updated, or update information (e.g., information such as Last-Modified) indicating the update time of the object file. .

For example, the cache control information embedding unit 120, as shown in FIG.
./css/2011/import_common.css Etag100
./css/2011/import_lib.jis Etag110
./css/2011/import_common2.css Etag120
./css/2011/import_common3.css Etag130
./css/2011/import_common4.css Etag140
./css/2011/import_common5.css Etag150 ...
A list of identification information is generated and embedded in an arbitrary location of the HTML file “index.html”. For example, “./css/2011/import_common.css” is information indicating which object file is the object file identified by the identification information “Etag100”.

  In the present embodiment, the cache control information embedding unit 120 has described a method of newly generating cache control information at the timing when the HTML file is analyzed and the object file is specified. However, the embodiment is not limited to this. It is not something that can be done. For example, the Web server 100 may separately generate or update an object file separately from the exchange with the Web client 200. At the time of generation or update, the Web server 100 generates identification information in association with the object file. There may be. Therefore, the cache control information embedding unit 120 may generate the cache control information by diverting already generated identification information and listing the diverted identification information. Alternatively, when the Web server 100 has already generated the cache control information as a list of identification information for each Web page, the cache control information embedding unit 120 does not analyze the HTML file and generates the generated cache control information. Control information may be diverted.

  Returning to FIG. 1, the HTML file response unit 130 of the Web server 100 transmits the HTML file in which the cache control information is embedded by the cache control information embedding unit 120 to the Web client 200.

  On the other hand, the cache control information extraction unit 240 of the Web client 200 extracts cache control information from the HTML file received from the Web server 100. Then, the cache determination unit 250 compares the cache control information extracted by the cache control information extraction unit 240 with the cache control information stored in the cache control information storage unit 220, and uses the cache control information extracted from the HTML file. It is determined whether the identified version of the object file has been stored in the cache 210.

  Since this is the first download of the Web page, the version of the object file identified by the cache control information extracted from the HTML file has not been stored in the cache 210 yet. Therefore, the cache control information storage unit 220 does not store the same cache control information as the cache control information extracted from the HTML file. Eventually, the cache determination unit 250 determines that all object files identified by all cache control information extracted from the HTML file have not been stored in the cache 210 (no cache hit).

  For this reason, the object file request unit 260 requests the Web server 100 to transmit all the object files using the acquisition destination described in the HTML file. Then, the object file response unit 140 of the Web server 100 transmits the object file in response to the request from the object file request unit 260. For example, the object file response unit 140 transmits the corresponding object file to the Web client 200 together with the response “200 OK”.

  Then, the object file request unit 260 stores a predetermined version of the object file received from the Web server 100 in the cache 210, and stores cache control information corresponding to the object file stored in the cache 210 into the cache control information storage unit 220. To store. In this case, the object file request unit 260 may store all the cache control information extracted from the HTML file in the cache control information storage unit 220.

FIG. 3 is a diagram for explaining the cache control information according to the present embodiment. Thus, after the first download of the web page, the cache control information storage unit 220, as shown in FIG.
./css/2011/import_common.css Etag100
./css/2011/import_lib.jis Etag110
./css/2011/import_common2.css Etag120
./css/2011/import_common3.css Etag130
./css/2011/import_common4.css Etag140
./css/2011/import_common5.css Etag150 ...
Such a list of identification information is stored.

  Next, the second download of the web page will be described. For example, when the same Web page is downloaded again, such as being reloaded by a user of the Web client 200, the HTML file request unit 230 transmits the request to the Web server 100 again.

  Similarly, on the Web server 100 side, again, the HTML file analysis unit 110 analyzes the HTML file, specifies an object file in which the acquisition destination is described in the HTML file, and the cache control information embedding unit 120 executes the cache control information. Are embedded in the HTML file. However, the cache control information embedding unit 120 embeds the latest cache control information at this stage. That is, for example, when an object file is updated, new identification information is given to the updated object file in response to the update, so the cache control information as a list of identification information is also updated. Cache control information.

FIG. 4 is a diagram for explaining an HTML file according to the present embodiment. For example, as shown in FIG. 4, it is assumed that the object file identified by “Etag110” is updated and given identification information “Etag115” that uniquely identifies the new version. Further, it is assumed that the object file identified by “Etag140” is updated and given identification information “Etag145” that uniquely identifies the new version. Therefore, the cache control information embedding unit 120, as shown in FIG.
./css/2011/import_common.css Etag100
./css/2011/import_lib.jis Etag115
./css/2011/import_common2.css Etag120
./css/2011/import_common3.css Etag130
./css/2011/import_common4.css Etag145
./css/2011/import_common5.css Etag150 ...
A list of identification information is generated and embedded in an arbitrary location of the HTML file “index.html”.

  Subsequently, when the HTML file response unit 130 transmits the HTML file in which the cache control information is embedded to the Web client 200, the cache control information extraction unit 240 of the Web client 200 performs cache control from the HTML file received from the Web server 100. Retrieve information. Then, the cache determination unit 250 determines again whether or not the object file identified by the cache control information extracted from the HTML file has been stored in the cache 210.

  Since this is the second download of the Web page, a part of the object file identified by the cache control information extracted from the HTML file, that is, an object file that has not been updated after the first download is stored in the cache 210. Stored. Therefore, the cache control information storage unit 220 also stores the same cache control information for a part of the cache control information extracted from the HTML file.

FIG. 5 is a diagram for explaining cache determination in the present embodiment. For example, the cache determination unit 250 includes cache control information extracted from an HTML file,
./css/2011/import_common.css Etag100
./css/2011/import_lib.jis Etag115
./css/2011/import_common2.css Etag120
./css/2011/import_common3.css Etag130
./css/2011/import_common4.css Etag145
./css/2011/import_common5.css Etag150 ...
Cache control information stored in the cache control information storage unit 220,
./css/2011/import_common.css Etag100
./css/2011/import_lib.jis Etag110
./css/2011/import_common2.css Etag120
./css/2011/import_common3.css Etag130
./css/2011/import_common4.css Etag140
./css/2011/import_common5.css Etag150 ...
And the cache control information identical to “Etag115” and “Etag145” is determined not to be stored. That is, the cache determination unit 250 determines that the version of the object file identified by “Etag115” and “Etag145” has not been stored in the cache 210 (no cache hit).

  Then, the object file request unit 260 requests the Web server 100 to transmit only the object file that is determined not to have a cache hit by the cache determination unit 250 using the acquisition destination described in the HTML file. For example, the object file request unit 260 includes an object file “./css/2011/import_lib.jis” corresponding to “Etag115” and an object file “./css/2011/import_common4.css” corresponding to “Etag145”. Is requested to the Web server 100. Then, the object file response unit 140 of the Web server 100 transmits the object file in response to the request from the object file request unit 260.

  The object file request unit 260 stores the object file newly received from the Web server 100 in the cache 210 and stores the cache control information corresponding to the object file stored in the cache 210 in the cache control information storage unit 220. To do. For example, the object file request unit 260 may store “Etag115” and “Etag145” in the cache control information storage unit 220.

  As described above, according to the above-described embodiment, whether or not the object file is the latest object file is collectively determined on the Web client 200 side, and only the necessary object file is requested to the Web server 100 side. As a result, inquiries that have been generated in large quantities and individually are greatly reduced, and it is possible to shorten the transfer time of the Web page. In other words, according to the above-described embodiment, cache control information is embedded in the HTML file that is the highest-level object, and the Web client 200 performs cache determination locally without going through the network, thereby reducing the transfer time of the Web page. It becomes possible to do.

  For example, consider the case of reloading a certain Web page (for example, a Web page indicated by the URL of http://www.ntt.co.jp/index.html). For example, in the conventional Web system, it is assumed that the Web client makes an inquiry about 86 times to the Web server, the transfer time of the Web page is approximately 9.804 seconds, and the data transfer amount is approximately 15 KB. According to the conventional Web system, for example, even if there are two updated object files, the Web client theoretically asks the Web server about 86 times again at the time of the second download. The page transfer time and the data transfer amount are not much different from the first time. On the other hand, according to the above-described embodiment, at the time of the second download, theoretically, the Web client needs to make two requests in order to acquire two object files. It is considered that the transfer time is about 1.7 seconds and the data transfer amount is about 0.5 KB. For example, when a Web client makes a request for acquiring a plurality of object files at a time, it is sufficient to make a single request, and the transfer time is theoretically 1.3 seconds. The amount of data transfer is considered to be about 0.2 KB.

  If so, when the above-described embodiment is applied, the request to the Web server is reduced by 97 to 98%, the transfer time is reduced by 82 to 87%, and the data transfer amount is reduced by 96 to 98%. Become a rate.

(Other embodiments)
Note that the Web system 10 described above may be implemented in various different forms other than the above-described embodiment.

  For example, in the Web system 10 described above, a method of using random number information (for example, information such as Etag) assigned every time an object file is updated as cache control information has been described. However, the embodiment is not limited thereto. It is not something that can be done. For example, update information (for example, information such as Last-Modified) indicating the update time of the object file may be used as the cache control information. In this case, for each object file, the cache determination unit 250 compares the update information extracted from the HTML file with the update information stored in the cache control information storage unit 220, and if both do not match (usually an HTML file) When the update time indicated by the update information extracted from the update information is newer than the update time indicated by the update information stored in the cache control information storage unit 220), it is determined that no cache hit occurs.

  Further, for example, it is possible to create a program in which processing executed by the Web server 100 or the Web client 200 according to the above-described embodiment is described in a language that can be executed by a computer. In this case, the same effect as that of the above-described embodiment can be obtained by the computer executing the program. Furthermore, the same processing as that of the above-described embodiment may be realized by recording such a program on a computer-readable recording medium, and reading and executing the program recorded on the recording medium. Hereinafter, an example of a computer that executes a program that realizes the same function as the Web server 100 and the Web client 200 illustrated in FIG. 1 will be described.

  FIG. 6 is a diagram illustrating a computer that executes a program that realizes the same function as the Web server 100 or the Web client 200 according to the present embodiment. As shown in FIG. 6, the computer has, for example, a memory, a CPU (Central Processing Unit), a hard disk drive interface, a disk drive interface, a serial port interface, a video adapter, and a network interface. Are connected by a bus.

  As shown in FIG. 6, the memory includes a ROM (Read Only Memory) and a RAM (Random Access Memory). The ROM stores, for example, a boot program such as BIOS (Basic Input Output System). The hard disk drive interface is connected to the hard disk drive as shown in FIG. The disk drive interface is connected to the disk drive as shown in FIG. For example, a removable storage medium such as a magnetic disk or an optical disk is inserted into the disk drive. The serial port interface is connected to, for example, a mouse and a keyboard as shown in FIG. The video adapter is connected to, for example, a display as shown in FIG.

  Here, as shown in FIG. 6, the hard disk drive stores, for example, an OS (Operating System), application programs, program modules, and program data. That is, the above-described program is stored in, for example, a hard disk drive as a program module in which a command to be executed by a computer is described. For example, a processing procedure for executing processing similar to that of the HTML file analysis unit 110, a processing procedure for executing processing similar to that of the cache control information embedding unit 120, and a processing procedure of executing processing similar to that of the HTML file response unit 130, A program module describing a processing procedure for executing the same processing as that of the object file response unit 140 is stored in the hard disk drive. Further, for example, a processing procedure for executing processing similar to that of the HTML file request unit 230, a processing procedure for executing processing similar to that of the cache control information extracting unit 240, and a processing procedure of executing processing similar to that of the cache determination unit 250 And a program module in which a processing procedure for executing processing similar to that of the object file request unit 260 is described is stored in the hard disk drive.

  Various data held by the Web server 100 and the Web client 200 described in the above-described embodiment are stored as program data in, for example, a memory or a hard disk drive. Then, the CPU reads program modules and program data stored in the memory and hard disk drive to the RAM as necessary, and executes each procedure.

  Note that the program modules and program data related to the above-described program are not limited to being stored in the hard disk drive, but may be stored in, for example, a removable storage medium and read by the CPU via the disk drive or the like. Alternatively, the program module and program data related to the above-described program are stored in another computer connected via a network (LAN (Local Area Network), WAN (Wide Area Network), etc.), and the CPU is connected to the CPU via the network interface. May be read.

DESCRIPTION OF SYMBOLS 100 Web server 110 HTML file analysis part 120 Cache control information embedding part 130 HTML file response part 140 Object file response part 200 Web client 210 Cache 220 Cache control information storage part 230 HTML file request part 240 Cache control information extraction part 250 Cache judgment part 260 Object file request part

Claims (4)

A control system including a server that transmits a Web page including an upper file, an object file in which the acquisition destination is described in the upper file, and a client that requests transmission of the Web page.
The server
An identification information for uniquely identifying the object file for each version for each update is embedded in the upper file, and the transmission unit transmits the upper file to the client.
The client
A cache for storing a predetermined version of the object file received from the server;
An identification information storage unit that stores the identification information corresponding to a predetermined version of the object file stored in the cache;
When the upper file is received from the server, the identification information is extracted from the upper file, the extracted identification information is compared with the identification information stored in the identification information storage unit, and the identification information extracted from the upper file A determination unit for determining whether or not the version of the object file identified by is already stored in the cache;
And a request unit that requests the server to transmit the object file using the acquisition destination described in the upper file when it is determined that the object file is not stored in the cache. And control system. The transmission unit embeds random number information in the upper file and transmits it to the client,
The determination unit compares whether or not the random number information extracted from the upper file matches the random number information stored in the identification information storage unit, and is identified by the random number information extracted from the upper file. 2. The control system according to claim 1, wherein it is determined whether or not the object file has been stored in the cache. The transmitting unit embeds update information indicating the update time of the object file in the upper file and transmits the embedded information to the client.
The determination unit compares the update information extracted from the high-order file with the update information stored in the identification information storage unit, and the update time indicated by the update information extracted from the high-level file indicates the identification information storage unit Whether or not the version of the object file identified by the update information extracted from the higher-level file has been stored in the cache is determined by determining whether or not the update time indicated by the update information stored in The control system according to claim 1, wherein the determination is performed. A control method executed by a control system including a server that transmits a Web page including an upper file and an object file in which the acquisition destination is described in the upper file, and a client that requests transmission of the Web page. ,
The server includes a transmitting step of embedding identification information for uniquely identifying the object file on a version basis for each update in the upper file and transmitting the upper file to the client;
The client includes a cache that stores a predetermined version of the object file received from the server, and an identification information storage unit that stores the identification information corresponding to the predetermined version of the object file stored in the cache,
The control method is:
When the client receives the upper file from the server, the client extracts the identification information from the upper file, compares the extracted identification information with the identification information stored in the identification information storage unit, A determination step of determining whether or not the version of the object file identified by the extracted identification information has been stored in the cache;
A request step of requesting the server to send the object file using the acquisition destination described in the higher-level file when it is determined that the object file has not been stored in the cache. Control method to do.

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