JP2006216081A - Data transfer device and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a proxy device for reducing load on a network without causing troubles in operation during multi-stage connection. <P>SOLUTION: A client side proxy 40 analyzes a received request header and checks whether a FP_USE header is added thereto or not. If the FP_USE header is not added thereto, the FP_USE header is added thereto and its information is stored in a header information storage part 403. With reference to the header information storage part 403 during reply, an owned proxy 40 is found to be most approximate to a client device 50 and such operation is performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a data transfer apparatus and a data transfer method for transferring data for another apparatus.

2. Description of the Related Art A client / server type information system is widely used, which includes a server that provides various services via a network and a client that requests a desired service from the server. In particular, the WORLD WIDE WEB system (or simply referred to as WEB) composed of a WEB server and a client that communicate using the HTTP protocol on the Internet is a client-server type information system that is very widely used. Normally, a server program operates on the server, and a predetermined tool (program) such as a browser operates on the client. The contents of services provided on the Internet are also diverse, providing information such as text, still images, moving images, audio (such as homepages, e-mails, digital contents, etc.) and programs via the network. Various services such as distribution or transfer services, electronic store services for selling products, reservation services for seats and rooms, mediation services for various contracts, etc., and new forms of services one after another Has appeared.

By the way, in a client-server type information system such as WEB, whatever service is provided, the service is basically provided by data transfer between the client and the server. Is done. Therefore, the capacity (bandwidth) of the network used for communication between the client and the server tends to become a bottleneck of the entire system. Therefore, a cache technique is usually used to reduce the load on the network.

In the case of a WEB system, browsers and the like that operate on a client often use a cache mechanism, and cache recently accessed data. In WEB, access is made by designating information or service with a name called URL, so that the cache on the client is the information that has been requested to the WEB server in the past and the data returned as a result of the service can be cached. The URL is recorded in the cache in association with the URL. In this case, if there is a request for the same URL information or service as that in the cache and it can be determined that the response data in the cache is not stale, by returning that data, Communication between can be eliminated.

When there are a plurality of users in a corporate office LAN, a research institution LAN, or a home LAN, a proxy server may be placed between the LAN and the Internet, and a cache mechanism may be provided in the proxy server. Many. The cache in the client (for example, the browser cache) operates as a cache dedicated to the client user, while the proxy server cache on the LAN operates as a shared cache for a plurality of client users. For this reason, in the latter case, the cache is effective even when accessing a URL accessed by another person (another client) in the past.

Now, in WEB, communication is performed between a client and a server using a protocol called HTTP. The HTTP protocol is a combination of a “request message” sent from the client to the server and a “reply message” that returns a response from the server to the client.

The request message consists of a “request header” and a “request body”. The request header includes a URL for designating information to be accessed and a service, a method name indicating the type of access, and other various information necessary for access. In the request body,
Enter the data to send to the server. The data contained in the request body is also called “request data”.

  The reply message includes a “reply header” and a “reply body”.

Information such as the status of the processing result is entered in the reply header, and data such as the requested information and the processing result of the requested service is entered in the reply body. The data contained in the reply body is also called “reply data”.

As a request message method, there are a “GET method” for reading information on the server, a “PUT method” for writing data held by the user to the server, and a “POST method” for sending back the result of processing in response to the request. It is the main thing used to access services. In addition, a method such as DELETE is defined.

In many cases, the request body of the request message of the GET method and the reply body of the reply message of the PUT method are empty. The request body of the POST method request message contains information used for processing on the server side as necessary, and the reply body of the POST method reply message contains data of the processing result.

Data read from the server by the GET method can be divided into “dynamic data” generated on the server side each time it is read, and “static data” that returns data already stored on the server side as it is. Of these, the contents of dynamic data may be different each time the same URL is read, and in many cases, the server sends back a specification indicating that caching is impossible in the header of the reply message. Therefore, it is a portion of static data that is subject to caching with WEB data. This static data can be divided into “shared data” that can be referenced by an unspecified number of users and “private data” that performs access control so that only specific users can access by authenticating users. . The former shared data can be cached in any cache. However, the latter private data cannot be cached in a shared cache such as a proxy server (because private data must be authenticated and sent back by the server). However, in the case of a personal cache such as a browser, even private data can be cached.

Since the POST method returns the result of processing on the server side, in general, the server sends back the result with a specification indicating that caching is impossible in the header of the reply message. Therefore, it is not normally subject to caching.

Since the PUT method sends data to the server, the cache does nothing.
Japanese Patent Laid-Open No. 11-025010

The conventional WEB cache targets static content as a cache target. In the past, information and services published on the WEB were not so frequently updated, and many were published to an unspecified number of people, so the proportion of static content was very high.
Even the conventional cache technology was effective in reducing the load on the network.

However, WEB-based ASP (Application Service P)
As a system in which users use a WEB browser to access information and services on a server via a network has become widespread, data that cannot be handled by the conventional cache technology is increasing as described below.

-Since the user is authenticated and the user who can access is restricted, there is much private data.

-Many dynamic data are generated by referring to the backend database.
-In many cases, the POST method is used for form processing and search.

  -The PUT method is often used to share information within a group.

As a result, the cache technology alone has not functioned effectively as a technique for reducing the load on the network.
The present invention has been made in view of the above circumstances, and provides a data transfer apparatus and a data transfer method including a cache technique and a compression technique that can further reduce the load on a network connecting data transfer apparatuses. The purpose is to provide.

In order to solve the above problems, a data transfer device according to the present invention provides a cache data and cache identification information that is identification information of the cache data in the data transfer device that relays communication between the first device and the second device. ID information cache means for performing an identification information cache for storing the information in association with each other, and a request receiving means for receiving a request message having a request header indicating a request for transmitting desired data to the second apparatus from the first apparatus When,
Analyzing means for analyzing the request header and analyzing whether or not the request message has passed through an identification information cache device for performing identification information caching, and via indicating whether or not the request message has passed through the identification information cache device Holding means for holding information; request transmitting means for sending the request message to the second device;
Corresponding to the reply message based on the reply receiving means for receiving from the second device a reply message corresponding to the request message and having a reply header and a reply body, and the route information held in the holding means. And determining means for determining whether or not the request message has passed through the identification information cache device, and when there is the reply body identification information in the cache identification information, the reply message is cached in the reply header. No-chat indicating that it should not
No-cha information adding means for giving information, and reply sending means for sending a reply message having a reply header to which the No-cha information is given to the first device.

As a result, the information added in the request message can be reflected in the reply message corresponding to the request message.

In particular, problems such as system configuration can be solved.

In addition, it is possible to provide a cache technique / compression technique that can further reduce the load on the network connecting a plurality of data transfer apparatuses without malfunctioning.

As a result, the information added in the request message can be reflected in the reply message corresponding to the request message.

In particular, problems such as system configuration can be solved.

The present invention relating to the apparatus is also established as an invention relating to a method, and the present invention relating to a method is also established as an invention relating to an apparatus.

Further, the present invention relating to an apparatus or a method has a function for causing a computer to execute a procedure corresponding to the invention (or for causing a computer to function as a means corresponding to the invention, or for a computer to have a function corresponding to the invention. It is also established as a program (for realizing) and also as a computer-readable recording medium on which the program is recorded.

According to the present invention, the correspondence between data and its name is held between data transfer devices, and the data having this correspondence is transferred by transferring the corresponding name instead of transferring the data. The amount of data transferred between devices can be reduced.

  Hereinafter, embodiments of the invention will be described with reference to the drawings.

In the following, a case where the WAN is the Internet, the client is connected to a LAN in the branch office 4 and the HTTP protocol is used will be described as an example.
Of course, the present invention uses a protocol other than the HTTP protocol regardless of whether the WAN is other than the Internet or the client is installed in a home LAN other than the branch office. Is also applicable.

FIG. 1 shows an example of the overall configuration of a computer network system to which the present invention is applied. In particular, three companies having different network configurations are illustrated here to show that there are various network configurations. ing.

Between the local area network (LAN) 12 in the ASP server center 2 and the local area network (LAN) 16 in each company branch, a wide area network (WAN) 14 such as the Internet or a dedicated line is connected between the branches. Company-wide LAN 18 to be connected
The server 20 in the ASP server center 2 and the client 50 in each branch office 4 can communicate with each other through the normal proxy 70 and the client-side proxy 40. One or more servers are connected to the LAN 12 within the ASP server center 2, and one or more clients are connected to the branch office LAN 16. In addition, other L in each company
The AN 18 is also usually connected via the proxy 70, the client side proxy 40, or directly.
A plurality of clients (not shown) are connected.

The WEB-based ASP provides services by various application programs from the server 20 installed in the server center 2 via the WAN 14 to each company, and the user uses a WEB browser on the client installed in the branch office 4. To access those services.

In this type of usage, the LAN 16 in the user office and the LA in the server center
The effective communication capacity (bandwidth) of the wide area network 14 such as the Internet among the networks with the N12 is the LAN 12 in the server center or the LA in the user office.
It is lower than N16 and the like, and this becomes a bottleneck in performance, causing a communication delay, resulting in a problem that the response performance of the application is lowered.

Therefore, in this embodiment, between the server 20 and the WAN 14 and between the client 50 and the WA.
By installing two modules, the server-side proxy 30 and the client-side proxy 40, between N14 and performing fingerprint compression (FP compression), which will be described later, between them, the amount of communication data is reduced. Eliminate bottlenecks.

The server 20, the server side proxy 30, the client side proxy 40, the client 50, and the normal proxy 70 of the present embodiment are all software (server program, server side proxy program, client side proxy program, client Program, usually a proxy program). In this case, an OS having a desired function of the computer, driver software, software such as packet communication software, encryption software, etc., or hardware such as a communication interface device, an external storage device, and an input / output device is mounted or connected as necessary. Is done. In this case, in order to input information from the user or the administrator or to present information to the user,
Preferably, a graphical user interface (GUI) is used.

On the client 50 used by the user to use the service, a program such as a WEB browser operates according to the purpose. A user uses a service by, for example, issuing a request message to a server that provides a desired service such as information transfer or order reception from the WEB browser, receiving a reply message, or repeating this appropriately. . Of course, instead of general-purpose software such as a WEB browser, other software such as dedicated software for using a specific service may be used. Further, the client may be not a general-purpose computer but a mobile phone terminal having an Internet function, for example.

A predetermined server program operates on the server 20 and provides a service specific to the server site to the user of the client 50.

As shown in FIG. 1, the server-side proxy 30 is connected to both the intra-server center LAN 12 and the WAN 14 and can be installed and operated so as to operate as a transparent proxy. Further, as shown in FIG. 2A, it can be installed on the server center LAN 12 and implemented. Further, as shown in FIG. 3A, the server-side proxy 30 can be implemented in the server 20.

Similarly, as shown in FIG. 1, the client-side proxy 40 is connected to the LAN 16 in the branch office and the LAN.
18 can be installed and implemented to operate as a transparent proxy. Further, as shown in FIG. 2B, it can be installed on the LAN 16 in the branch office. Further, as shown in FIG. 3B, the function of the client side proxy 40 can be implemented in a browser or the like that operates on the client 50. Alternatively, a personal client-side proxy 40 on a client 50 such as a browser.
Can also be implemented.

Further, the client side proxy 40 is connected between the WAN 14 and the LAN 18, for example.
In addition to relaying between the AN 14 and the LAN 18, it may be further provided as a proxy for a plurality of clients 50 (not shown) at the head office (for example, the middle company in FIG. 1).

The normal proxy 70 is also, for example, between the WAN 14 and the LAN 18 and between the WAN 14 and the LAN 18.
18 may be further provided as a proxy for a plurality of clients 50 (not shown) at the head office (for example, the upper company in FIG. 1). The normal proxy 70 refers to an HTTP proxy server that is generally used at present. The server-side proxy 30 and the client-side proxy 40 have a function of reducing communication data by performing FP compression described later. It refers to a new HTTP proxy server having

In the above computer network system, the conceptual flow of the present embodiment will be described with reference to FIGS.

FIG. 4 shows an operation flow when the Web content on the server 20 is cached in the server side proxy 30 and the client side proxy 40.

First, in order to read out the Web content stored in the desired server 20 from the browser of the client 50 in the branch 4, the user designates the URL of the Web content and makes a request.

This request is notified to the server 20 via the network (FIG. 4A). Upon receiving this notification, the server 20 reads the requested Web content and transmits it to the server-side proxy 30 (FIG. 4-2). The server-side proxy 30 receives the received Web
The content fingerprint (FP) is calculated (FIG. 4-3). Calculated FP as W
It is received and stored in correspondence with the eb content (FIG. 4-4). Further, the server-side proxy 30 replies the received Web content to the branch office (FIG. 4-5).

The client side proxy 40 prints the fingerprint of the received Web content (
FP) is calculated (FIGS. 4-6). The calculated FP is received in correspondence with the Web content and stored (FIGS. 4-7). The client-side proxy 40 sends Web content to the client 5
Transmit to 0 (FIGS. 4-8). As described above, the Web contents are cached in the server side proxy 30 and the client side proxy 40, respectively.

Next, FIG. 5 shows an operation flow when Web contents are already cached in the server side proxy 30 and the client side proxy 40.

First, in order to read out the Web content stored in the desired server 20 from the browser of the client 50 in the branch 4, the user designates the URL of the Web content and makes a request.

This request is notified to the server 20 via the network (FIG. 5-1). Upon receiving this notification, the server 20 reads out the requested Web content and transmits it to the server-side proxy 30 (FIG. 5-2). The server-side proxy 30 receives the received Web
The page fingerprint (FP) is calculated (FIG. 5-3). Same F as the calculated FP
A search is performed to determine whether P is already stored in the server-side proxy 30 (FIG. 5-4). Here, since the same FP as the calculated FP has been stored, the server-side proxy 30 does not transmit the received Web content to the branch, but instead replies the FP to the branch (FIG. 5). 5). The client side proxy 40 searches the own apparatus with the received FP (FIG. 5-6). The Web content stored in association with the found FP is retrieved (FIGS. 5-7). The client-side proxy 40 transmits the Web page read from its own device to the client 50 (FIGS. 5-8). As described above, the Web content to be transmitted from the server side proxy 30 to the client side proxy 40 is converted into a small amount of FP.
In particular, the bottleneck of the wide area network can be eliminated.

  Now, the fingerprint will be described in detail.

The server side proxy 30 and the client side proxy 40 of this embodiment are both
It has a cache mechanism called a fingerprint cache (FP cache). The fingerprint cache is named HTT by the name called fingerprint (FP).
Records and manages data exchanged with the P protocol.

As illustrated in FIG. 6, the fingerprint is determined by a predetermined calculation method (hash function in the example of FIG. 6) from the contents of data exchanged by the HTTP protocol (content in the example of FIG. 6). It ’s a short number. This number may be variable length,
From the viewpoint of ease of processing, fixed-length numerical values are easier to handle.

As a method for calculating the fingerprint, well-known MD-5 and SHA-1
A hash function such as can be used. These hash functions are used for digital signatures on data, and when given data is converted into a 128-bit number for MD-5 and a 160-bit number for SHA-1. can do. The features of these hash functions are given two data X1 and X2, and data X1 and data X2
Are the same as the hash value calculated for the data X1 and the hash value calculated for the data X2, but if two different data A and B are given, the data A The hash value calculated for the data B and the hash value calculated for the data B are different with a very high probability (in principle, the hash values calculated for two different data A and B, respectively). The values may be the same, but the probability is small enough to be ignored in practice).

As shown in FIG. 7, the fingerprint cache (60 in the figure) of the server-side proxy 30 and the client-side proxy 40 has a data body (61 in the figure) exchanged in the past by the HTTP protocol. The fingerprint value (62 in the figure) calculated from the above is recorded and managed as a name.

For example, when transferring data from the server-side proxy 30 to the client-side proxy 40 using the HTTP protocol, the server-side proxy 30 calculates a fingerprint of the data, and the data corresponding to the fingerprint is stored in the fingerprint cache. Then, since the data (data having the same content) has been transferred in the past, the corresponding fingerprint value is transferred without transferring the data. The client-side proxy 40 that has received the fingerprint can reproduce the data to be transferred by extracting the data corresponding to the fingerprint value from the fingerprint cache. By using this method (ie, data compression-> data transfer-> data decompression), it is only necessary to send the fingerprint value if it is the same data that was sent in the past. Can do. Of course, the same applies when transferring data from the client-side proxy 40 to the server-side proxy 30.

For the sake of explanation, when transferring data between the server-side proxy 30 and the client-side proxy 40, the fingerprint cache is used to replace the message body data with the fingerprint and compress the transfer information amount. Compression (F
This is called P compression).

It should be noted that FP compression is applied to all messages between the server-side proxy 30 and the client-side proxy 40 (that is, a process for replacing data with a fingerprint using a fingerprint cache). However, for example, in order to exclude application to a message that cannot be expected to have a fingerprint cache effect, a message that satisfies a predetermined condition is excluded from the application target of FP compression (always FP compression is not performed). May be transferred).

The predetermined condition in this case is, for example, that predetermined information is described in the message header. Specifically, for example, information indicating a GET method and information indicating a request are described in a message header. Another example of the predetermined condition is that the data to be transferred is null or has a very short size.

Of course, there are various other variations. A plurality of conditions may be used in combination.

By the way, between the client 50 and the server 20, as shown in the overall configuration example of the computer network system to which the present invention of FIG. 1 is applied, there are various others between the branch office 4 and the ASP server center 2. In general, the proxy device is interposed.
Here, for example, in FIG. 1, between the branch office 4 and the ASP server center 2,
1) When going through a normal proxy (upper right of Fig. 1),
2) When going through the client-side proxy (middle right in Fig. 1)
3) When going through the client side proxy and the normal proxy (lower right of Fig. 1)
The three types are shown. Although not shown, in another company connected to the WAN 14, a plurality of clients (browser) are connected only through the normal proxy 70 without introducing the client-side proxy 40 (currently common) There may be another company (configured in network form).

As described above, when a proxy is interposed between the branch office 4 and the ASP server center 2, the client-side proxy 40 of the branch office 4 and the server-side proxy 3 of the ASP server center 2.
At 0, simply applying fingerprint compression as described above causes the following problems.

a) The server-side proxy 30 that has received the reply message for the request cannot determine whether the reply message should be converted into FP (if possible) or transmitted without being converted into FP. In other words, if the request is via the normal proxy 70 only, the normal proxy 70 does not have the FP function, so the converted version must not be sent, but if the request is via the client side proxy 40. If the FP of the reply message to be transmitted is stored, the FP may be sent. However, at present, it cannot be determined whether or not the FP should be sent.

b) Further, for example, when the normal proxy 70 is interposed between the server-side proxy 30 and the client-side proxy 40, the fingerprint function that is not available with the cache function provided in the normal proxy 70 is also cached.

c) For example, the client-side proxy 40 is located between the branch office 4 and the ASP server center 2.
Is present, the intermediate client-side proxy 40 cannot recover that it is an intermediate proxy, and thus restores and returns it.

Therefore, the server-side proxy and client-side proxy of the present embodiment solve these problems.

FIG. 8 and FIG. 9 show functional block diagrams of the client side proxy 40 and the server side proxy 30 of this embodiment, and will be described in detail. 8 and 9 mainly show the functional configuration when transferring data between the client-side proxy 40 and the server-side proxy 30. FIG.

  Here, first, a request message and a reply message will be described.

The request message is composed of a request header and a request body as shown in the [Prior Art] column, and the request header contains information to be written by the user in addition to an area for storing predetermined information. Includes definable areas. In this embodiment, when a request message is transferred by the client-side proxy 40, information indicating that it has passed through a proxy that performs FP compression is written in an area definable by the user. Here, FP_USE is written, and this is called an FP_USE header.

The reply message is composed of a reply header and a reply body as shown in the [Prior Art] column, and the reply header contains an H in an area where predetermined information is stored.
A NO_CACHE header that can be recognized by a device compatible with the TTP protocol can be added. This NO_CACHE header means that reply body caching is prohibited. In the present embodiment, the server side proxy 30 writes NO_CACHE in this area. Therefore, an apparatus compatible with the HTTP protocol does not cache the FP if the received reply message has a NO_CACHE header. The reply header includes an area in which information to be written by the user can be defined in addition to an area in which predetermined information is stored. In the present embodiment, when the reply body is an FP value subjected to FP compression, an FP header is added to an area definable by the user.

  The configuration of the client side proxy 40 will be described below using FIG.

The receiving unit 401 receives a request message from the client 50. The header analysis unit 402 receives the request message received by the reception unit 401, analyzes the request header, and detects the presence or absence of the FP_USE header. When the header analysis unit 402 detects a request message having an FP_USE header, the header information storage unit 403 stores information indicating that the request message has an FP_USE header.

When the header analysis unit 402 detects a request message that does not include the FP_USE header, the header addition unit 404 adds FP_ to the request header of the request message.
A USE header is added. The transmission unit 405 transmits the request message sent from the header analysis unit 402 or the header addition unit 404 to the server 20.

The receiving unit 406 receives a reply message that is a response to the request message. When the header determination unit 407 receives the reply message, the header determination unit 407 determines whether or not the FP_USE header is included in the request message corresponding to the reply message with reference to the header information storage unit 403. The header information storage unit 4
03 is FP in the header of the request message as shown in the request message.
Since it is stored when _USE is included, the header information storage unit 40
3 means that this client-side proxy 40 is not the client-side proxy 40 closest to the requested client 50, and that no information is in the header information storage unit 403. This means that the client-side proxy 40 is the client-side proxy 40 that is closest to the requested client 50.

If the header determination unit 407 determines that the client side proxy 40 is not the client side proxy 40 closest to the client 50, the header determination unit 407 transmits the received reply message to the transmission unit 413 as it is. If the header determination unit 407 determines that the client side proxy 40 is the client side proxy 40 closest to the client 50, the header determination unit 407 supplies the reply message to the FP compression determination unit 408.

The FP compression determination unit 408 determines whether or not the reply message is FP compressed by detecting whether or not the received reply message includes an FP header. The FP compression determination unit 408 sends a reply message to the FP cache management unit 409 if the FP compression is performed, and to the FP compression processing unit 414 if the FP compression is not performed.

The FP cache 411 stores the FP that has been previously FP compressed and the content before compression of the FP in association with each other.

The FP compression processing unit 414 performs fingerprint compression. FP compressed F
The P value is stored together with the content by the FP cache registration unit 410 by the FP cache 411.
Registered in

The FP cache management unit 409 uses the FP in the reply message as the FP cache 4
11, the content corresponding to the searched FP is obtained, the reply data of the reply message is changed to the obtained content, and sent to the transmission unit 413. FP
The cache registration unit 410 receives the reply message from the FP compression determination unit 408, obtains the FP of the reply data (content), associates the FP with the content, and sets the F.
Register in the P cache 411. Thereafter, a reply message is sent to the transmission unit 413.

The transmission unit 413 transmits the received reply message to the client 50.

Note that, as functional blocks, the receiving unit 401 and the receiving unit 406, the transmitting unit 405 and the transmitting unit 41 are used.
3 are illustrated as separate block configurations, but the same configuration may be used, and the receiving unit 40 may be the same.
Of course, 1 and the transmission unit 413, and the reception unit 405 and the reception unit 406 may be the same as the transmission / reception unit.

  The above is the configuration of the client side proxy 40.

  Next, the configuration of the server side proxy 30 will be described.

The receiving unit 301 receives a request message. The header analysis unit 302 analyzes the request header of the request message, checks whether or not the FP_USE header is added, and if the FP_USE header is added, the header information storage unit 30
3 is notified.

The header information storage unit 303 stores information indicating that the FP_USE header is attached to the request message. Then, the request message is transmitted from the transmission unit 304 to the server 20. The server 20 receives the request message, takes out the desired content requested from the client 50, and uses it as a reply message.
Transmit to the client 50.

The receiving unit 305 receives the reply message from the server 20 by the receiving unit 305. When the header determination unit 306 receives the reply message from the reception unit 305, the header determination unit 306 refers to the header information storage unit 303 and determines whether an FP_USE header is added to the request message corresponding to the reply message. This determination corresponds to determining whether or not the client side proxy 40 exists while the request message is traced. If there is no header (there is no client-side proxy), the header determination unit 306 sends a reply message to the transmission unit 311 as it is. When the header determination unit 306 determines that there is a header, the header determination unit 306 sends a reply message to F
The data is sent to the P compression processing unit 307.

The FP compression processing unit 307 performs FP compression using the fingerprint compression method described above,
An FP is generated. The FP cache management unit 308 searches the FP cache 309 with the FP received from the FP compression processing unit 307. When found, the reply data of the reply message is changed to FP and sent to the header adding unit 310. If the FP cache management unit 308 does not find the FP in the FP cache 309, the FP cache registration unit 312 registers the FP and data in association with each other in the FP cache 309, and sends the reply message to the transmission unit 311 as it is. The header adding unit 310 adds a NO_CACHE header to the header of the reply message from the FP cache management unit 308 and supplies the NO_CACHE header to the transmission unit 311.

  The above is the configuration of the server-side proxy 30.

FIG. 10 shows an example of the processing procedure of the client side proxy 40 when receiving one request message from the client.

The client side proxy 40 receives the request message from the client from the LAN 16 or the LAN 18 by the receiving unit 401 (step S101). The header analysis unit 402 analyzes the request header of the received request message, and performs FP_
It is detected whether or not a USE header is added (step S102). Step S10
If the FP_USE header is added as a result of 2, the header information storage unit 403 stores information indicating that the FP_USE header is attached to the request message (step S103), and transmits the received request message as it is. The transmission unit 405 transmits the request message to the server-side proxy 30.

On the other hand, as a result of step S102, if the FP_USE header is not added, the header adding unit 404 adds FP_U to the predetermined area of the request header of this request message.
The SE header is added, and the transmission unit 405 transmits the request message with the FP_USE added to the server side proxy 30 (step S105).

In this embodiment, a communication method is assumed in which a connection is maintained until a reply message is received after the client 50 transmits a request message. For this reason, the header information storage unit 403 may be provided with a minimum 1-bit flag indicating whether or not the request message has an FP_USE header. Note that the present invention is not limited to this communication method, and if it is a method that handles a plurality of connections by switching them in parallel, the previous flag and the identification information for identifying the request message are stored in association with each other. Various methods can be applied, such as, for example.

FIG. 11 shows an example of a processing procedure of the server side proxy 30 when one request message is received via the WAN 14.

The server side proxy 30 receives a request message by the receiving unit 301 (step S201). The header analysis unit 302 analyzes the request header of the received request message and detects whether or not the FP_USE header is added (step S2).
02). If the FP_USE header is added as a result of step S202, the header information storage unit 303 stores information indicating that the FP_USE header is attached to the request message (step S203). The received request message is sent to the transmission unit 304.
To the server 20 (S204).

The server 20 receives the request message, performs processing by a known method, and transmits a reply message to the client from which the request message is issued.

FIG. 12 shows the server-side proxy 3 when one reply message is received from the server 20.
An example of the processing procedure of 0 is shown.

The server side proxy 30 receives a reply message from the server 20 by the receiving unit 305 (step S301).

The header determination unit 306 refers to the header information storage unit 303 (step S302) and determines whether an FP_USE header has been added to the request message corresponding to the reply message (step S303). In other words, it is determined whether or not at least one client side proxy 40 exists between the client 50 and the server 20 (server side proxy 30).

As a result of step S303, if it is determined that FP_USE is not added, the reply message is transmitted as it is to the client 50 via the WAN 14 by the transmission unit 311 (step S309).

On the other hand, if it is determined in step S303 that FP_USE has been added, the FP compression processing unit 307 obtains the FP of the reply data (= content) of the reply message (step S304). Then, the FP cache management unit 308 obtains the obtained FP.
The fingerprint cache 309 is searched using as a key (step S305), and the F
It is confirmed whether or not a set of the value of P and the data corresponding thereto is registered in the fingerprint cache 309 (step S306).

As a result of step S306, if the FP is registered in the FP cache 309, the header adding unit 310 adds NO_CACHE to the header of the reply message (step S).
307). Then, the reply data of the reply message is changed to the FP obtained in step S304, and an FP header is added, and the transmission unit 311 transmits the data to the client 50 via the WAN 14 (step S308).

As a result of step S306, if the FP is not registered in the FP cache 309, F
The P cache registration unit 312 associates the fingerprint value with the reply data (using the fingerprint value as a key), and prints the fingerprint cache 309.
(Step S310). Then, the transmitting unit 311 transmits the reply message as it is to the client 50 via the WAN 14 (step S311).

FIG. 13 shows an example of the processing procedure of the client side proxy 40 when one reply message is received.

The client side proxy 40 receives the reply message by the receiving unit 406 (step S401).

The header determination unit 407 refers to the header information storage unit 403 (step S402) and determines whether FP_USE has been added to the request message corresponding to the reply message (step S403). This means that the client side proxy 40
It is determined whether or not the client side proxy 40 exists between the client 50 and the client 50. For example, of the two client side proxies 40 in the middle right of FIG.
The header information storage unit 403 of the left client side proxy 40 stores that FP_USE was added, and the header information storage unit 403 of the right client side proxy 40 did not have FP_USE added. So do not save anything.

If it is determined in step S403 that FP_USE has been added, the reply message is transmitted as it is to the client 50 via the LAN 14 or the like by the transmission unit 413 (step S411).

If it is determined in step S403 that FP_USE is not added, the FP compression determination unit 408 determines whether or not the reply data is FP compressed by checking the presence or absence of the FP header of the reply header (S404). ). If there is a NO_CACHE header, FP compression has been performed.

If the FP compression is performed as a result of step S404, the reply data of the reply message is FP, and the FP cache management unit 409 searches the fingerprint cache 411 using the reply data (= FP) as a key (step S404). S405). The content corresponding to the fingerprint found by this search is read, and the reply data of the reply message is changed to this content (step S406).
The transmission unit 413 transmits the changed reply message to the client 50 (step S407).

As a result of step S404, if FP compression is not performed, the FP compression processing unit 414 calculates the FP of reply data (= content) (step S408). The FP cache registration unit 410 calculates the obtained fingerprint and the reply data (= content)
Are registered in the fingerprint cache 411 (using the fingerprint value as a key) (step S409). Then, the transmission unit 413 transmits the reply message as it is to the client 50 (step S410).

According to the embodiment of the present invention that has been described above, the client-side proxy 40 operates according to the arrangement location. For example, if the client side proxy 40 is the client side proxy closest to the client 50, the reply data to be transmitted to the client always supplies raw data (FP uncompressed). Further, for example, if the client side proxy 40 is an intermediate proxy, the client side proxy 40 operates to transfer only without processing any reply data. Since it operates in this way, a system that can operate normally even when the client side proxy 40 or the normal proxy 70 is connected between the server side proxy 30 and the client side proxy 40 can be constructed. .

Even if a normal proxy exists, it operates normally without erroneously caching FP data.

Note that the client-side proxy 40 of the present embodiment adds FP_
When the USE header is attached, the information indicating that the FP_USE header is attached is stored. Conversely, when the FP_USE header is not attached to the request message, the information indicating that the FP_USE header is not attached. May be saved. Similarly, when the request message does not have the FP_USE header, information indicating that the FP_USE header has been added (by the client side proxy 40) may be stored. In such a case, the header determination unit 407 causes the client-side proxy 40 closest to the client 50 when the information is stored in the header information storage unit 403.
Can be treated as Further, the header information storage unit 403 is set as a flag indicating the presence or absence of the FP_USE header, and the header determination unit 407 determines whether or not the client side proxy 40 is closest to the client 50 by turning on / off the flag. It may be good.

Further, the server-side proxy 30 according to the present embodiment is configured to transmit only the data or the FP value to the reply message to be transmitted, but when the FP value is stored and the data is transmitted (S306). In the case of NO), the FP value may be sent along with the reply message. With such a configuration, the client-side proxy 40 needs to have a function of extracting the FP value from the received reply message, but the function of performing the FP compression becomes unnecessary, and the overall speed is increased. It will be possible.

By the way, until now, all data included in one message is subject to FP compression (
For example, when the data included in one message is composed of a set of data in a predetermined unit, only a part of the unit data included in one message is registered. It is also possible to adopt a configuration that is a target for FP compression (a target to be registered in the fingerprint cache).

  Each function described above can be realized as software.

The present embodiment can also be implemented as a program for causing a computer to execute predetermined means (or for causing a computer to function as predetermined means, or for causing a computer to realize predetermined functions), The present invention can also be implemented as a computer-readable recording medium on which the program is recorded.

Note that the configuration illustrated in the embodiment of the present invention is an example, and is not intended to exclude other configurations, and a part of the illustrated configuration may be replaced with another or one of the illustrated configurations. Other configurations obtained by omitting a part, adding another function or element to the illustrated configuration, or combining them are also possible. Also, another configuration that is logically equivalent to the exemplified configuration, another configuration that includes a portion that is logically equivalent to the exemplified configuration, another configuration that is logically equivalent to the main part of the illustrated configuration, and the like are possible. is there. Further, another configuration that achieves the same or similar purpose as the illustrated configuration, another configuration that achieves the same or similar effect as the illustrated configuration, and the like are possible.

In addition, various variations of various components illustrated in the embodiment of the present invention can be implemented in appropriate combination.

Further, the embodiment of the present invention is an invention of an invention as an individual device, an invention of two or more related devices, an invention of the entire system, an invention of components within an individual device, or a method corresponding thereto. The invention includes inventions according to various viewpoints, stages, concepts, or categories.

Therefore, the present invention can be extracted from the contents disclosed in the embodiments of the present invention without being limited to the exemplified configuration.

The present invention is not limited to the embodiment described above, and can be implemented with various modifications within the technical scope thereof.

The figure which shows the structural example of the computer network system which concerns on one Embodiment of this invention. The figure which shows the other structural example of the computer network system which concerns on the embodiment. The figure which shows the further another structural example of the computer network system which concerns on the embodiment. The figure which shows the basic concept of the computer network system which concerns on the embodiment. The figure which shows the basic concept of the computer network system which concerns on the embodiment. The figure which shows the fingerprint of the embodiment. The figure which shows the fingerprint cache of the embodiment. The functional block diagram of the client side proxy 30 of the embodiment. The functional block diagram of the server side proxy 30 of the embodiment. 6 is a flowchart showing a procedure example of a client side proxy according to the embodiment. The flowchart which shows the example of a procedure of the server side proxy which concerns on the same embodiment. The flowchart which shows the example of a procedure of the server side proxy which concerns on the same embodiment. 6 is a flowchart showing a procedure example of a client side proxy according to the embodiment.

Explanation of symbols

2 ... ASP server center 4 ... Branch offices 12, 16, 18 ... LAN
14 ... WAN
16 ... LAN in user office
DESCRIPTION OF SYMBOLS 20 ... Server apparatus 30 ... Server side proxy apparatus 40 ... Client side proxy apparatus 50 ... Client apparatus 60 ... Normal proxy apparatus 301,305,401,406 ... Receiving part 302,402 ... Header analysis part 303,403 ... Header information storage part 304, 311, 405, 413 ... transmission unit 306, 407 ... header determination unit 307, 414 ... FP compression processing unit 308, 409 ... fingerprint cache management unit 309, 411 ... FP cache 310, 404 ... header addition unit 312, 410 ... Fingerprint cache registration unit 408 ... Fingerprint compression determination unit

Claims (3)

In a data transfer device that relays communication between a first device and a second device,
Identification information cache means for performing an identification information cache for storing cache data in association with cache identification information that is identification information of the cache data;
Request receiving means for receiving a request message having a request header indicating a request for transmitting desired data to the second device from the first device;
Analyzing means for analyzing the request header and analyzing whether the request message has passed through an identification information cache device for performing identification information cache;
Holding means for holding route information indicating whether or not the request message has passed through the identification information cache device;
Request transmission means for transmitting the request message to the second device;
A reply receiving means for receiving a reply message corresponding to the request message and having a reply header and a reply body from the second device;
Determining means for determining whether or not the request message corresponding to the reply message has passed through the identification information cache device based on the route information held in the holding means;
No-ch indicating that the reply message should not be cached in the reply header when the reply body identification information is included in the cache identification information.
No-chae information adding means for giving ache information;
A data transfer apparatus comprising: a reply transmission unit configured to transmit a reply message having a reply header to which the No-chach information is given to the first apparatus. 2. The data transfer apparatus according to claim 1, wherein the No-chach information is an instruction for prohibiting caching of data included in the reply message in an apparatus capable of handling an HTTP protocol. In a data transfer method for relaying communication between a first device and a second device,
An identification information cache that stores cache data and cache identification information that is identification information of the cache data in association with each other is stored in the identification information cache means,
A request receiving means indicates a request to transmit desired data to the second device, receives a request message having a request header from the first device,
Analyzing means, analyzing the request header, analyzing whether the request message has passed through the identification information cache device for performing identification information cache,
Holding means for holding route information indicating whether or not the request message has passed through the identification information cache device;
A request transmission means for transmitting the request message to the second device;
A reply receiving unit receives a reply message corresponding to the request message and having a reply header and a reply body from the second device,
In the determination unit, based on the route information held in the holding unit, determine whether the request message corresponding to the reply message has passed through the identification information cache device,
When the reply body identification information is included in the cache identification information, the reply header is provided with No-chach information indicating that the reply message should not be cached.
A data transfer method characterized in that a reply transmission means transmits a reply message having a reply header provided with the No-chach information to the first device.

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