JP2000057041A - Proxy server and lan system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a fast response and to increase the document retrieving speed by reading the document requested by a Web client out of a Web server to present it to the Web client and pre-reading a document concerning the requested document to temporarily store it together with a copy of the requested document. SOLUTION: A Web server 104 serves as an information presenter and is connected to an internet 103. A Web client 100 is connected to a LAN 101. A proxy server 102 relays a request of the client 100 to the sever 104, transfers the document sent from the server 104 to the client 100, reads a document concerning the requested document out of the server 104 in addition to the requested document except the requested document and holds the requested document and a copy of the document related to the requested document in its own memory. That is, if the same document and/or the relative documents are requested by the different clients 100, no access is given to the server 104 and the same document or the relative documents are supplied from the server 102.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a proxy server used in an intranet in which a LAN is extended, and a LAN system using the same.

[0002]

2. Description of the Related Art As a network in a company, there is a LAN using a high-speed line. An intranet is a LAN extension system that connects a LAN to the Internet outside the company and exchanges information with the outside of the company. An intranet includes a LAN, an information terminal such as a workstation or a personal computer connected to the LAN (this is called a Web client), a Web server as an information provider, and a Web server.
It comprises an Internet connected to a server, and a proxy (proxy is a proxy) server as a proxy response means interposed between the Web client LAN and the Internet to assist in the exchange of information.

[0003] Thus, a Web client is a LAN client.
, Information can be exchanged with other Web clients, and information can be exchanged with the outside via the Internet. Further, the Web client can also search for various types of information possessed by the Web server. At this time, by interposing a proxy server,
Many Web clients connected to one LAN
You can now receive information through a proxy server.

[0004] In particular, a proxy server often has a function of temporarily holding information. This temporary hold is
Called cache. A search for the same information (document) may be requested between Web clients connected to the LAN. In such a case, the previously searched document is held in the proxy server using the cache function, and a Web client (regardless of whether it is self or another) searches for the document later. If so, the proxy server provides the document to the search request Web client. In this case, the Web that connects to the Internet
There is no need to access the server, and information can be retrieved from the proxy server, which enables high-speed information retrieval.

FIG. 7 shows a comparison between an example having no cache function in a proxy server and an example. The LAN and the Internet are omitted in the drawing, and a Web client, a Web proxy server, and a Web server are shown as resources. As is apparent from this figure, in the example having the cache function, the access to the Web server is unnecessary, so that the search can be speeded up.

[0006]

Since the Web proxy server is used by a plurality of clients (persons), the documents requested by each person are different from each other. Therefore, it becomes more difficult to specify a document as the number of Web proxy server users increases. If you keep documents in advance,
The frequency of viewing the held document decreases as the number of Web clients increases, and the response time of the document requested by the Web client becomes slow.
There is a need to improve the proxy server and make the response time to Web clients faster.

[0007] It is an object of the present invention to provide a proxy server and a LAN system which enable a high-speed response and a high-speed document search by expanding a cache function.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a proxy server interposed between a LAN and the Internet and performing a proxy response of information between a Web client connected to the LAN and a Web server connected to the Internet.
A proxy server is disclosed in which a document requested by a Web client is read from a Web server and provided to the Web client, and a document related to the document is prefetched and temporarily stored together with a copy of the requested document.

Further, the present invention provides a proxy server interposed between a LAN and the Internet and performing a proxy response of information between a Web client connected to the LAN and a Web server connected to the Internet, comprising a cache memory; A copy of the document requested by the Web client and a copy of the document related to the document are held in the cache memory, and when a document request is received from the Web client, whether or not the same document as the requested document exists in the cache memory And a proxy server that reads out the requested document and the related document from the Web server if not, stores the requested document and the related document in the cache memory, and sends the requested document to the requesting client. Further, the present invention discloses a proxy server in which a counter for designating the capacity of a related document is provided, the related document is read from the Web server up to the designated capacity, and stored in a cache memory.

The present invention further includes a LAN, a plurality of Web clients connected to the LAN, and a proxy server interposed between the Web server connected via the Internet and the LAN to perform a proxy response of information. At the same time, the proxy server reads a sentence requested by the Web client from the Web server and provides the read document to the Web client, prefetches a document related to this document, and temporarily holds the document together with a copy of the requested document,
A LAN system that is used for subsequent requests from Web clients will be disclosed.

As described above, the Web client is
A document related to a document requested to the proxy server is read and held by the proxy server along with the request document. As a result, even if there is a search request for a document related to this document other than the requested document, the proxy server can immediately provide this information to the Web client.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The Internet is a WWW (Worl).
d wide Web) and TCP / IP (Transmisso
n Control Protocol / Internet Protocol) as the connection means. TCP / IP is a connection means that performs route control in the Internet connecting a plurality of networks and realizes highly reliable communication from end to end.

FIG. 6 shows an example of the Internet. The in-house network 101 has a high-speed line (for example, 1
0Mbps to 100Mbps) LAN.
A large number of personal computer terminals (including workstations and other information devices) 100A are connected to the AN 101. The personal computer terminal 100A is a Web client 10
0. The personal computer terminal 100A is a mere terminal for the LAN 101, but the W terminal on the intranet
Call it an eb client.

The Web server 104 is a provider of information (often in the form of a file), and is provided to the Internet 103 (low-speed line, for example, 28.8 kbps to 12
8 kbps). Many Web clients are directly or indirectly connected to the Internet 103. In the figure, the LAN 101 is a Web owned by a proxy responder.
The connection is made indirectly via the proxy server 102. The Web client 100 is further connected to the LAN 101. The proxy server 102 communicates with the client 100
Is relayed to the server 104, the document transferred from the server 104 is transferred to the client 100, and a document related to this document other than the requested document is read from the server 104 to copy the requested document and the related document. Keep it in its own memory. The holding of the copy is for receiving the same document and / or related document from the server 102 without accessing the server 104 when a request for the same document and / or related document is received from a different client 100. It is a means that enables high-speed response. Retention is also called a cache because it is a temporary storage and uses a memory that can respond quickly.
The holding memory for that is called a cache memory. There is an example of the server 102 without a cache. W
The web client 100 has a WWW browser (Brower) as a system for information search. The browser is a tool that enables the user to search for information on the WWW, which is a homepage of the Internet, without knowing the detailed file structure and the like. A typical example is "mosaic".

The operation of retrieving product information about the company H from the Web client 100 using the above browser is as follows. First, a document (Web document) is requested and displayed from the browser. It is assumed that the document is described in HTML (details will be described later). FIG. 3 shows an example of document selection. FIG. 3 is a diagram for performing a link-type information search by selecting a keyword in the displayed document relating to the company H. In FIG. 3, a document 41 is first displayed, and four selection items appear. For example, one of them, "product introduction" is selected. With this selection, Document 4
2 is displayed on the screen. If "washing machine" is selected from document 42, document 42 appears. If "refrigerator" is selected, document 4 is displayed.
5 appears. If "What's New" is selected from the document 41, the document 43 appears. On the other hand, the browser analyzes an HTML (Hyper Text Language) file constituting the document. HTML refers to a language that describes hypertext for enabling enormous information scattered on the Internet to be freely accessed without considering distance at all. When a homepage is established on the Internet to provide information, the information is described in such HTML so that it can be linked to related information. The text format and other content can be expressed using only letters. H
A TML file is a file described in HTML.

FIG. 4 shows an HTML file 51 and a document 42 which is an analysis result thereof. The HTML file 51 has items 52A and 53A representing links, items 54A representing images, and items 55A representing links using graphics. By analyzing such a file 51, a document 42 as shown on the left of FIG. 4 is obtained. Here, 52 is 52A, 53
Corresponds to 53A, 54 corresponds to 54A, and 55 corresponds to 55A. Such document analysis is similarly performed on the documents 41, 43, 44, 45, and the like. Then, the analysis results become documents 41, 43, 44, and 45.

FIG. 5 shows a client 100 and a server 10
4 shows a state of mutual access with the C.4. LA on the way
N104, proxy server 102, Internet 10
3 is omitted. The server 104 constructs the document H
It holds TML files, graphic files, and image files, and transfers the files to the client 100 in response to a request from a browser mounted on the client 100. On the other hand, the proxy server 102 independently requests the Web server 104 for a document related to the requested document other than the requested document, fetches the document together with the requested document, and holds a copy. FIG. 1 shows a processing flow in the intranet including the reading (read ahead) of the related document. However, the LAN and the Internet as intermediate routes are omitted for simplification of the drawing.

The Web client 100 performs a file request process 1 to the Web proxy server 102. In response to a request from the Web client 100, the Web proxy server 102 performs reception processing 2, and performs cache search processing 3 to determine whether the requested file is held as a cache. If the file is held as a cache, the transmission process 9 to the client is performed. If the file is not held, the We
A Web information request process 4 to the b server 104 is performed. We
In response to a request from the Web proxy server 102, the b server 104 performs Web information reception processing 5, and transmits the requested file to the Web proxy server 102 as a file 6. Web proxy server 102
b, the file reception processing 7 is performed by the file transmission from the server 104, the cache writing processing 8 of the Web proxy server 102 is performed, the transmission processing 9 to the client 100 is performed, and the cache read ahead processing 10 is performed.
I do. The Web client 100 performs a file reception / display process 11 from the Web proxy server 102.

Next, the cache prefetch processing 10 of FIG. 1 will be described with reference to FIG. It is determined whether the file requested by the Web client 100 is an HTML file 21,
If the file is not an HTML file, the process ends. HTM
If the file is an L file, it is a file that constitutes a document, so the URL in the file (eg, 52A, 53 in FIG. 4)
A, 54A, 55A) are extracted 22. Where URL
Is an abbreviation of Uniform ResourceLocator, and refers to a description method for specifying a server used on the Internet and a link destination of a file in the server. In many cases, the protocol, host name, port number, and file name are described in this order. The extracted URL is a document linked to the document requested by the Web client 100 (document of the next hierarchy or page), or an image or graphic file in the document requested by the Web client 100. If the file indicated by the extracted URL holds a file as a cache, a determination process 29 is performed to determine whether the file requested by the Web client 100 is an HTML file.
If the file is not stored, a Web information request process 24 is performed to the Web server 104 that stores the file. In response to a request from the Web proxy server 102, the Web server 104 performs Web information reception processing 25, and transmits the requested file to the Web proxy server 102 as a file 26.

[0020] The Web proxy server 102
The Web information receiving process 27 is performed by the file transmission 26 from the server 104, and the Web proxy server 102
Of the cache write process 28 of FIG. Next, a determination process 29 is performed to determine whether the file requested by the Web client 100 is a file in the HTML format. If the file is not in the HTML format, the process is terminated. (The initial value of the counter is 0). If the counter is 1, one-layer prefetch processing of the document requested by the Web client 100 has been performed, and the processing ends. If the counter is 0, the substitution processing 31 of 1 is performed on the counter, and the URL extraction processing 2
Then, the same process is performed.

Request Document of Web Client 100 and W
The cache look-ahead document of the web proxy server 102 will be described with reference to FIG. 3. When the web client 100 requests the document 41, the web proxy server 102
Responds the document 41 to the Web client 100,
The document 42 and the document 43 are written into the cache of the Web proxy server 102. Further, when the Web client 100 selects “・ Product Introduction” from the document 41, the Web proxy server 102
The document 42 held as a cache of the proxy server 102 is replied to the Web client 100, and the document 44 and the document 45 are written to the cache of the Web proxy server 102. Therefore, before the Web client 100 (which is different from the same client, there are many examples of requests from the same client), a file related to the document requested by the Web client 100 is requested before the Web proxy 100 makes a request. Server 102
Since the prefetch is held as a cache, a high-speed response at the time of a request from the Web client 100 is possible.
In addition, by increasing the numerical value of the determination process 27 as to whether the counter in FIG. 2 is 1, it is possible to easily expand the hierarchy to be read ahead.

According to FIGS. 1 and 2 described above, a file related to a document requested by the Web client 100 is always read ahead and held before the Web client 100 requests it. Since the document is not previously requested but is held in advance as a cache, a high-speed response is possible. In addition, by increasing the value of the counter number determination (process 30 in FIG. 2), it is possible to easily expand the range of prefetching, and it is effective as a prefetching device for high-speed response.

FIG. 8 shows a processing flow before and after the improvement and a response time. This figure shows the difference in response time when the Web client 100 requests the document 41 of FIG. 3 with the request 1 of FIG. 8 and browses it, and then requests the document 42 of FIG. 3 with the request 2 of FIG. Before the improvement, after a request is issued from the Web client 100, the Web proxy server 102
The request is made to the server 104, but after the improvement, after the request 1 is issued and before the request 2 is issued, the Web proxy server 102 makes a request to the Web server 104 and stores it as a cache. Client 100
Thus, a high-speed response to the request is possible.

Various embodiments will be described below. (1) Deletion of related documents: If a certain period of time has passed since the document was retained, the document is deleted in, for example, a FIFO format, so that the cache capacity is reduced and unnecessary information is not retained. Further, since the related document is often requested from the same client, the related document may be deleted when there is no search request from the client. (2) Specifying and judging acquisition of related documents ... Although the related documents are voluntarily judged by the proxy server 102, the system may be such that the client can specify whether to request the related documents. It is possible. Then, the size of the related document is determined on the proxy server side. (3) Contents of related documents: In addition to lower layers and next pages in a hierarchical relationship, figures and images related to the documents are also included. The proxy server may determine whether there is any relation. In addition, pre-reading can be performed by setting related standards in advance and referring to them. (4) Examples other than documents: Examples of general information are also possible.

[0025]

According to the present invention, in addition to the search request document, the related document is read ahead by the proxy server.
High-speed search is now possible even when there is a search request for related documents.

[Brief description of the drawings]

FIG. 1 is an overall processing flowchart of a Web proxy server system of the present invention.

FIG. 2 is a processing flowchart of the Web proxy server of the present invention.

FIG. 3 is a screen transition example of a Web system.

FIG. 4 is a diagram showing a Web browser and an HTML file.

FIG. 5 is a configuration diagram of a Web client and a Web server.

FIG. 6 is a diagram illustrating a configuration example of a general Web proxy server.

FIG. 7 is a response time flow diagram depending on the presence or absence of a cache;

FIG. 8 is a flow chart of response time before and after improvement.

[Explanation of symbols]

 Reference Signs List 100 Web client (information terminal) 101 LAN 102 Web proxy server 103 Internet 104 Web server

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B075 KK07 KK14 KK33 ND16 NK10 PQ05 5B082 AA00 BA00 FA03 FA12 HA02 HA05 HA08 5K030 GA01 HC01 HC14 HD05 HD06 5K033 AA02 DA06

Claims (4)

[Claims] 1. A proxy server interposed between a LAN and the Internet for performing a proxy response of information between a Web client connected to the LAN and a Web server connected to the Internet, wherein a document requested by the Web client is sent to the Web server. A proxy server for reading from a server and providing it to a Web client, prefetching a document related to the document, and temporarily storing the document together with a copy of the request document. 2. A proxy server interposed between a LAN and the Internet and performing a proxy response of information between a Web client connected to the LAN and a Web server connected to the Internet, comprising: a cache memory; A copy of the requested document and a copy of the related document are held in the cache memory, and when a document request is received from the Web client, a check process is performed to determine whether or not the same document as the requested document exists in the cache memory. A proxy server that reads the requested document and the related document from the Web server if not, and stores the requested document and the related document in the cache memory and sends the requested document to the requesting client. 3. The proxy server according to claim 1, wherein a counter for designating the capacity of the related document is provided, and the related document is read from the Web server up to the designated capacity and stored in the cache memory. . 4. A communication system comprising: a LAN; a plurality of Web clients connected to the LAN; a proxy server interposed between the Web server connected via the Internet and the LAN to perform a proxy response of information; The proxy server reads a sentence requested by the Web client from the Web server and provides the read document to the Web client, prefetches a document related to the document, temporarily holds the document together with a copy of the request document, and stores the subsequent Web document.
LAN system used for requests from clients.