JP2002073451A - Mobile system, method for transmitting html file from server to client and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce, in a mobile system, the amount of communication data between a server computer and a client computer, thereby realizing a low communication cost and a high response speed. SOLUTION: This method includes the following steps; (a) Before a server 1 transmits a HTML file to a client 7 through a communication network 6, an analysis part 12 analyzes and separates plural kinds of the contents of the HTML file; (b) The server 1 performs data compression or data contraction for the contents of the HTML file depending on the attributes of the kinds of the contents using an image part 13 and a TEXT part; (c) The server 1 transmits the HTML file including the contents processed by data compression or data contraction to the client 7 through the communication network 6; and (d) The client 7 receives the HTML file, and decompresses the contents processed by data compression using a decompression part 71 to display by a WWW browser.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates generally to a method and apparatus for transmitting data from a server to a client. The present invention is particularly applicable to a high-speed and low communication cost client from a server using a public wireless packet communication network.
The present invention relates to a method and an apparatus for transmitting a TML file.

[0002]

2. Description of the Related Art Recently, a portable terminal is carried around and connected to a server from outside by using a public wireless packet communication network for mobile communication.
A so-called mobile system for acquiring and displaying an rkuplanguage file (also referred to as a hypertext file) is used. According to this mobile system, anytime and anywhere, it is possible to take out necessary data and contents from a WWW (World Wide Web) server on the Internet or a server for an intranet in the company, and display and use them. Convenient and convenient. As a conventional example of such a mobile system, for example, Japanese Patent Application Laid-Open No. 10-21165,
JP-A-10-260890 and JP-A-2000-260
No. 76155 discloses this. Such a mobile system generally transmits data and contents from a server to a mobile terminal as a client using a public wireless packet communication network for mobile communication. The packet communication fee is not a charge proportional to the connection time or the distance, but a charge method based on the amount of communication data, that is, the number of packets. However, even in a mobile system using such a relatively advantageous public wireless packet communication network for mobile communication, high packet communication charges cannot be denied. In particular, when a large number of employees have portable terminals to access a server from a location and access a large amount of HTML files containing various contents such as images, the communication cost cannot be ignored. For this reason, Japanese Unexamined Patent Application Publication No.
A technique disclosed in Japanese Patent Publication No. 65 is proposed. In this method, image data in an HTML file is reduced to a low image quality mode in which the size or color is reduced, and text data is transmitted only from the heading or the beginning of the sentence to a few lines. However, in this technology, although text information usually contains more necessary information than image data, it is transmitted to the client only in a few lines from the heading or sentence, so the client Has the disadvantage that necessary information cannot be obtained. Text data can be easily compressed and decompressed, has a high compression ratio, and can be completely restored by decompression. Utilizing this, JP 2
Japanese Patent Application Publication No. 000-76155 discloses that a text portion in an HTML file is compressed and transmitted. However, since this technique has a configuration in which a compressed text file is stored in a server in advance, when an HTML file is browsed from the outside via the Internet, it is compressed and stored in a storage unit and then transferred to a terminal. There is a disadvantage in that the procedure is not responsive to a request from a client. Also, Japanese Patent Application Laid-Open
Japanese Patent Application Laid-Open No. 260890 discloses a configuration in which a server separately compresses a text portion and an image portion of an HTML file based on information from a client according to a specification corresponding to a client environment and transmits the compressed file to a client. However, in this configuration, when the server sends the HTML file to the client, the user or the browser first sends the client environment to the server, and it takes time to prepare the HTML file according to the specifications, and the response is also responsive. There is a disadvantage of lacking.

[0003]

In order to solve the above-mentioned conventional disadvantages, the present invention provides a mobile client with a method for transferring a large amount of HTML files including a plurality of types of contents such as images to a mobile client at a current communication speed of, for example, about 64 Kbps. Provided is a method capable of transmitting a response quickly even when using a public wireless packet communication network for body communication. SUMMARY OF THE INVENTION It is an object of the present invention to simultaneously solve the above two problems of high packet communication cost and low response speed at a low communication speed.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention separates and analyzes an HTML file including a plurality of types of contents on a server side, compresses the file, and transmits it on a client side. The extension reduces the amount of packet transmission between the server and the client, thereby realizing low packet communication cost and high-speed response.
According to the present invention, in a method of transmitting an HTML file containing a plurality of types of contents from a server to a client via a communication network and displaying the HTML file on a WWW browser on the client, (a) the server transmits the HTML file to the client via the communication network Immediately before sending via the HTML file, the contents of the HTML file are analyzed and separated, and (b) the server
Data compression or data reduction is performed on the contents of the HTML file in accordance with the type attribute. (C) The server transmits the HTML file including the data compression or data reduction contents to the client via the communication network, d)
A method is provided having steps for a client to receive an HTML file, decompress the data-compressed content, and display the decompressed content on a WWW browser.

According to the method of the present invention, the server
The content of the ML file can use a compression or reduction algorithm that is optimal for each type of attribute. For example, if the HTML file includes a text part and an image part, the text part is compressed by about half the data amount using an algorithm with a high compression ratio and transmitted from the server, paying attention to the point that the redundancy is relatively high. In the corresponding decompression algorithm. On the other hand, the image portion is originally large in data, and the client is often a mobile terminal, and the display screen is VGA (640).
x480), half VGA (640 × 240) or noting that there are many cases where the number of pixels is smaller than that, the image data is reduced from the image size or the number of display colors is reduced and transmitted from the server. Is displayed as image data with reduced number of pixels or reduced display color. Even in this case, there is no practical problem since the important contents of the HTML file information are often in the text portion. As a result, the amount of data communicated between the server and the client can be reduced, and a high-speed response and a reduction in communication cost can be realized.

Also, in the method of the present invention, before step (a), (e) the server sends one
The method may further include a step of collectively receiving an HTML file having a plurality of types of contents from the WWW server in response to one request. Before the client request is actually sent to the server in step (e), (f)
The server may further include a step of pre-reading the HTML file from the WWW server and storing the file in a storage device in the server. Further, the data compression of the text portion in step (b) may use an algorithm in a ZIP format. Further, the communication network of step (c) may be a public wireless packet communication network. Further, the client may be a mobile terminal. Further, in the method of the present invention, the communication network is a local area network (LA).
N), the server proceeds with steps (a), (b),
An HTML file is transmitted to the client without performing (c), and the client performs H.sub.H without performing step (d).
A TML file may be displayed. In this way, when the server and the client are connected via the office LAN, there is no need to consider the cost of the communication fee and the communication speed is high, so that the compression and decompression of the HTML file is not performed. The display quality may be improved by transmitting from the server to the client and receiving and displaying by the client.

According to another aspect of the present invention, a server for transmitting an HTML file to a client via a communication network analyzes the contents of the HTML file immediately before transmitting the HTML file to the client via the communication network. Analysis and separation means for separating according to the type of content;
Compression means for performing data compression on the text portion of the ML file;
Transmission means for transmitting a TML file to a client via a communication network.

According to the server of the present invention, the text portion of the HTML file can be compressed by using an optimal compression algorithm. In other words, paying attention to the fact that text data has relatively high redundancy, the data amount is compressed to about half the average by an algorithm with a high compression ratio,
The ML file is transmitted from the server, and the client completely restores the compressed text portion of the received HTML file with the corresponding decompression algorithm. The client uses an HTML file containing the text portion decompressed and restored in this way, and displays it using a WWW browser. Since an important part of the data information of the HTML file is a text part, there is no practical problem. As a result, the amount of data communicated between the server and the client can be reduced, and a high-speed response and a reduction in communication cost can be realized.

In response to a single request from a client, a server sends an HT having a plurality of types of contents from a WWW server.
A receiving means for collectively obtaining ML files may be further provided. Further, before the request from the client, the receiving means may further include means for pre-reading the HTML file from the WWW server and storing it in a storage device in the server.

According to another aspect of the present invention, a means for receiving an HTML file from a server via a communication network and displaying the compressed HTML file from the server at a client displayed by a WWW browser. And a means for decompressing the compressed text portion, and a means for displaying the content in an HTML file containing the decompressed text portion by the WWW browser. According to the client of the present invention, an HTML file in which a text portion is data-compressed is received from a server and displayed, so that the amount of data communicated between the server and the client is reduced, thereby achieving a high-speed response and a reduction in communication cost. A reduction can be realized. The client may be a mobile terminal.

According to yet another aspect of the present invention, an HTM is transmitted from a server to a client via a packet radio communication network.
In a mobile system for transmitting an L file and displaying it by a WWW browser on a client, a server collects an HTML file having a plurality of types of contents from a WWW server in response to one request from a client; Analysis / separation means for analyzing the contents of an HTML file immediately before transmitting the HTML file to a client via a communication network and separating a text portion; data compression means for performing data compression on a text portion of the HTML file; Transmitting means for transmitting an HTML file including a compressed text portion to a client via a communication network, wherein the client is a portable terminal and receives an HTML file including a data compressed text portion from a server. Means,
Means for decompressing a data-compressed text portion and WW using an HTML file containing the decompressed text
Means for displaying by a W browser. The receiving means of the server sends the request from the WWW server to H before the request from the client.
A means for pre-reading the TML file and storing it in a storage device in the server may be further provided. According to the mobile system of the present invention, a high-speed response and a reduction in communication cost can be realized by reducing the amount of data communicated between the server and the client.

[0012]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 schematically illustrates an overall mobile system according to a preferred embodiment of the present invention. The server computer 1 constructs a corporate intranet, and includes a corporate local area network (LAN) or a wide area network (WA).
N) 2 communication networks. A client computer 3 can access the server 1 via the LAN 2. The server 1 is also accessible from a mobile client computer 7 of a portable terminal via a public wireless packet communication network 6 for mobile communication and its base station 61. The server 1 further connects to any WWW server 5 in the world via the Internet and
P (Hypertext Transfer Prot)
ocol), an HTML file can be obtained.
In response to a request from the client 3 and the mobile client 7, the server 1 extracts data including an HTML file from its storage device HDD (shown in FIG. 2) and distributes the data to the requesting clients 3 and 7. In addition, the server 1 responds to requests from the client 3 and the mobile client 7 via the Internet 4 to obtain a URL.
(Universal Resource Locat
or) obtains an HTML file from the WWW server 5 specified in (or) and distributes it to the requesting client 3 and mobile client 7. The server 1 sends the HTML specified by the URL requested by the mobile client 7
WWW server 5 or HD collectively collectively stores a plurality of types of contents included in one file (one screen) of the file, that is, a plurality of types of contents such as text data and image data.
D, the contents are analyzed and compressed or reduced by a method described later and transmitted to the mobile client 7.

The server 1 uses, for example, one or several Pentium III (registered trademark) processors manufactured by Intel Corporation of the United States, and has a main memory (not shown) of 512 MB.
Dozens of GB for hard disk drive storage HDD
And a PC server using Windows NT (registered trademark) of Microsoft Corporation as an operating system. The client 3 connected to the LAN 2 is, for example, a personal computer using a Windows 98 (registered trademark) or Windows CE (registered trademark) operating system of Microsoft Corporation of the United States, and an Ethernet (registered trademark) for LAN 2 connection. It may have a modem 34. The client 3 further includes a WWW browser provided with a decompression unit 31 (FIG. 2) as data decompression means for decompressing a compressed text portion of the received HTML file as described later. As the mobile client 7 of the mobile terminal, for example, Windows CE (registered trademark) of Microsoft Corporation in the United States is used as an operating system, and has a liquid crystal screen 75 of VGA (640 × 240 dots) and half VGA (640 × 240 dots). DoPa (registered trademark)
May be a small notebook-type personal computer having a packet wireless communication modem 74 corresponding to. The mobile client 7 also has a WWW browser provided with a decompression unit 71 (FIG. 2) as data decompression means for decompressing a compressed text portion of an HTML file received as described later.

The HTML file is composed of a plurality of types of contents such as character data, image data, and downloadable files displayed on the display screen of the client computer 3 or 7 using a WWW browser on the client computer 3 or 7. including. HTML
The file contains HTML statements that control these displays. The display character data and the HTML command sentence are distinguished into either the display character or the command sentence by the surrounding tags.
This is the text part of the L file. The image data is, for example, GIF (Graphics Interchange)
Format) or JPEG (Joint Photo)
graphic image coding Exp
(rts Group) format image data representing a still image such as a photograph, and is data that increases in proportion to the number of pixels and the number of display colors. There are various types of files that can be downloaded. For example, the image data, files created by Microsoft Word (registered trademark) or Excel (registered trademark), programs, PDs, etc.
F (Portable Document Format)
t) format files.

[0015] As described above, the HTML file includes various kinds of contents, that is, text data, still image data, moving image data, programs, downloadable files such as words and Excel, and is also called WWW contents. As described above, there are various types of contents of the HTML file, and the type can be generally specified by an extension of the file name. For example, the extension gif given to a file name is GIF format still image data, jpg etc. is JPEG format still image data, doc etc. is a word file, xls etc. is an excel file, and html is HTML. Since it refers to a file in the format, the type of file can generally be determined.

GIF format and JPEG format image files are already considerably compressed based on human visual perception and data correlation. To compress more, the number of pixels is reduced to reduce the screen size. Reduce the size or
Reducing the number of display colors to reduce the number of colors is the only effective data reduction method. On the other hand, command statements and display characters in the HTML format are text data and therefore have considerable redundancy.
Focusing on this redundancy, for example, if compression is performed using a compression algorithm in the ZIP format, a compression ratio of up to nearly 50% is possible. The compressed file can easily be completely restored to the original data using the decompression algorithm. Also,
Downloadable files can also be compressed considerably if they are word files or excel files.

FIG. 2 is a block diagram showing the functions of the mobile system of the present invention shown in FIG. These functions of the server 1 are realized by hardware or software. FIG. 3 shows a flowchart of a process performed in the server 1. In response to the request from the mobile client 7, the server 1 obtains an HTML file from the storage device HDD by the transmission / reception unit 11 or from the WWW server 5 via the Internet 4 (step 30).
1). In step 301, the server 1 collectively collects a plurality of types of contents of an HTML file, such as text data and image data, included in one page to be displayed in response to one URL request from the client 7. The data is acquired from the WWW server 5 and compressed according to the data type by a method described later. Further, the server 1 pre-empts the request from the client 7 and performs HTML before the request.
The file is obtained from the WWW server 5 and the storage device HDD
Alternatively, the HTML file stored from the storage device may be sent to the requesting client 7 after data compression / reduction described later, immediately upon receiving a request from the client 7. This HTML file contains various kinds of contents as described above. HTML
Immediately before transmitting the file to the mobile client 7 via the public packet wireless communication network 6 for mobile communication, the server 1 analyzes the contents of the HTML file by the analysis unit 12 (step 302). The analysis unit 12 analyzes the contents of the HTML file using the extension of the file name as described above, and separates the HTML file into the image part 13 and the text part 14 (step 303).

Since the image portion 13 has already been considerably compressed based on the human visual sense and data correlation as described above, the image size is reduced by reducing the number of pixels (pixels). The image data is reduced by the reduction unit or the image reduction unit 15 that reduces the number of display colors to reduce the number of colors (step 304). On the other hand, the text part 14 is
Is compressed using a ZIP-format compression algorithm (step 305). When using the ZIP format,
The average compression ratio of the text portion is high, about 50%. The HTML file including the compressed text portion and the reduced image portion is transmitted from the transmission / reception section 11 to the mobile client 7 (step 306). The transmission of the HTML file between the server 1 and the mobile client 7 uses the public packet radio communication network 6, and the transmission data is transmitted after being encapsulated in a form conforming to the protocol used. As described above, the server 1 retrieves the HTML file from the WWW server 5 or retrieves the HTML file from the HDD after receiving a request from the mobile client 7 in step 301, and compresses or reduces the file according to the data type and transmits it as it is. Therefore, before sending the compressed or reduced data to the client 7,
There is no need to memorize in D, and it is excellent in responsiveness. Also, when sending to the mobile client 7, the server is always in HTM even if there is no instruction from the mobile client 7.
Since the data is compressed or reduced according to the type of the content of the L-file and transmitted, there is no need to perform compression after receiving a compression transmission instruction from the client 7 at the time of HTML transmission, and the responsiveness is excellent. Further, in step 301, when the server 1 receives a URL request from the client 7, the server 1 transmits a plurality of types of content included in an HTML file corresponding to one page to be displayed, that is, data corresponding to a text portion or a plurality of image portions. , The client 7 collects the data from the WWW server 5 or the HDD at once, so that the client 7 can send
For example, there is no need to perform a request session for each text or a plurality of images, and it is responsive to a request from the client 7.

Referring again to FIG. 2, a functional block diagram of the mobile client 7 of the mobile system of the present invention is shown. In the mobile client 7, these functions can be realized by hardware or software. FIG. 4 shows a flowchart of a process performed in the client 7. The mobile client 7 sends an HTML message from the server 1 via the public packet radio
A transmission / reception unit 72 for receiving a file, and a received HTM
A display unit 73 for displaying the L file by a WWW browser. The WWW browser of the mobile client 7 has a decompression unit 71 for decompressing the compressed text portion of the received HTML file. Upon receiving the HTML file (step 401), the mobile client 7 checks the content and the compression state of the received HTML file (step 402). This is H
The presence or absence of compression of the TML file, compression method information, and information on the data length after compression are checked. It is determined whether or not the compressed text is included and the compression method is the zzip format (step 403), and the compressed text portion is restored to the original text portion by the decompression section 71 (step 40).
4) Display is made on the display unit 73 (step 405).
On the other hand, the reduced image portion is displayed as it is (go directly from step 403 to step 405). Therefore, the image portion on the display screen of the client 7 is displayed in a form in which the image is reduced or the display color is reduced. But,
There is no problem because the text part is completely restored.

Similarly to the text part, the attached file is analyzed and separated by the analysis unit 12 and compressed in the ZIP format by the compression unit 16 before being transmitted from the server 1 to the mobile client 7. The attached file thus compressed is decompressed by the decompression unit 71 after being received by the mobile client 7, and can be completely restored. As described above, the data amount of the HTML file to be transmitted is reduced by about half in the text portion, so that the number of transmission packets can be reduced, the communication cost and the communication time can be greatly reduced, and the response can be speeded up. And lower communication costs.

Referring again to FIG. 2, a client 3 connected to the LAN 2 is shown. The client 3 may be the same as the mobile client 7, for example, when the employee uses the mobile client 7 used on the go while connected to the office LAN 2. It may be something. The client 3 has a transmission / reception unit 32 for receiving an HTML file from the server 1 via the LAN 2 and a display unit 33 for displaying the received HTML file on a WWW browser on the client 3. The WWW browser of the client 3 further has a decompression unit 31 for decompressing the HTML file compressed from the server 1.
Even in the case of the client 3 connected to the LAN 2, the server 1 may compress and reduce the data as in the case of transmitting the HTML file to the mobile client 7. However, in the case of the client 3 connected to the LAN 2, since it is not necessary to consider the communication cost and the communication speed is relatively high, the HTML file is transmitted from the server 1 as it is without compressing or reducing the data. The HTML file may be displayed directly without passing through the decompression unit 31 so that the image quality does not deteriorate due to the data reduction of the image portion.

As described above, according to the mobile system of the present invention, when an HTML file is transmitted from a server to a client, data is compressed or reduced in accordance with the attribute of the content of the file to perform packet transmission. This has the effect of reducing the amount of data to reduce the communication cost between the server and the client, and at the same time realizing a faster response response.

[Brief description of the drawings]

FIG. 1 is a diagram showing an entire mobile system including a server and a client according to the present invention.

FIG. 2 is a block diagram showing functions of a server and a client of the mobile system of the present invention.

FIG. 3 is a flowchart showing a process in a server.

FIG. 4 is a flowchart showing a process in the client.

[Explanation of symbols]

 Reference Signs List 1 server 2 local area network (LAN) 3 client 4 Internet 5 WWW server 6 public packet wireless communication network 7 mobile client 12 analysis unit 13 image part 14 text part 15 image color reduction unit 16 compression unit

Claims (15)

[Claims] An HTML file containing a plurality of types of contents is transmitted from a server to a client via a communication network,
In the method of displaying by a client WWW browser, (a) the server sends the H
Immediately before transmitting the TML file via the communication network,
Separating the content of the HTML file according to the type; (b) the server compressing or reducing the content according to the attribute of the type; (c) the server
Transmitting the HTML file containing the compressed or reduced content to the client via the communication network;
(D) the client sends the HTM from the server
Receiving an L-file and decompressing the compressed content for display by the WWW browser. 2. The method according to claim 1, wherein the plurality of types of contents include a text portion and an image portion, and the text portion is compressed in the step (b), and the image portion is reduced by reducing the number of pixels or the number of display colors. The HT with the text portion expanded in d) and the reduced image portion
The method of claim 1, wherein the display is in an ML file. 3. Before the step (a), (e) the server, upon one request from the client,
3. The method according to claim 1, further comprising the step of collectively receiving an HTML file including the plurality of types of content from a WWW server. 4. In the step (e), before the client request is actually sent to the server,
4. The method of claim 3, further comprising the step of: (f) the server pre-reading the HTML file from a WWW server and storing it in a storage device in the server. 5. The method according to claim 2, wherein the compression of the text portion in the step (b) uses an algorithm according to a ZIP format. 6. The method according to claim 1, wherein the communication network in the step (c) is a public wireless packet communication network. 7. The method according to claim 1, wherein the client is a portable terminal. 8. When the communication network is a local area network, the server performs the step (a);
(B) to the client without performing (c)
The method according to any of the preceding claims, wherein a TML file is transmitted and the client displays the HTML file without performing step (d). 9. HTML to a client via a communication network
A server for transmitting the file, immediately before transmitting the HTML file to the client via the communication network, analyzing the contents of the HTML file and separating a text portion of the HTML file; A server comprising: compression means for performing data compression of the text part of an HTML file; and transmission means for transmitting the HTML file having the compressed text part to the client via the communication network. 10. The server according to claim 9, wherein said server further comprises receiving means for collectively obtaining said HTML file having a plurality of types of contents from a WWW server in response to one request from said client. 11. The server according to claim 10, wherein said receiving means further includes means for prefetching said HTML file from a WWW server and storing it in a storage device in said server before a request from said client. 12. A client which receives an HTML file including a text portion from a server via a communication network and displays the HTML file on a WWW browser, wherein the HT in which the text portion is compressed from the server.
A client comprising: means for receiving an ML file; means for decompressing the compressed text portion; and means for displaying by the WWW browser using the HTML file having the decompressed text portion. 13. The client is a portable terminal,
HTML of multiple types of contents from the server in one request
The client of claim 12, further comprising means for receiving a file. 14. A mobile system in which an HTML file is transmitted from a server to a client via a packet radio communication network and displayed by a WWW browser on the client, wherein the server responds to one request from the client by a WWW. The HT having a plurality of types of contents from a server
Receiving means for collectively obtaining an ML file; analyzing / separating means for analyzing the contents of the HTML file immediately before transmitting the HTML file to the client via the communication network and separating a text portion of the HTML file Compression means for performing data compression on the text portion; and the HTM having the data-compressed text portion
Transmitting means for transmitting an L-file to the client via the communication network, wherein the client is a portable terminal, and the HT including a text portion compressed from the server.
Means for receiving an ML file; means for decompressing the compressed text portion; and means for displaying on the WWW browser using the HTML file including the decompressed text portion. And mobile system. 15. The server according to claim 14, wherein said receiving means of said server further includes means for pre-reading said HTML data from said WWW server and storing it in a storage device in said server before a request from said client. The described mobile system.