Scalable derivative services

• US 7,793,220 B1
• Filed: 01/22/2001
• Issued: 09/07/2010
• Est. Priority Date: 08/29/2000
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Chauhan, Abhishek, Liang, Sheng, Mirani, Rajiv, Chang, Oliver, Zhang, Hong
• Primary Examiner(s): Hutton; Doug
• Assistant Examiner(s): Tran; Quoc A
• Application Number:
  US09/767,365
• Time in Patent Office: 3,515 Days
• Field of Search: 715/513, 715/523, 715/511, 715/530, 715/234, 715735-739, 715/757, 715/854, 707/1, 707/10, 707/9, 707/103.R, 709/217, 709/226, 709/227, 709/203, 709/230, 709/201, 709/247, 713/154, 705/1
• US Class Current: 715/738
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching
• CPC Class Codes: G06F 16/958 Organisation or management of web site content, e.g. publishing, maintaining pages or automatic linking
• CPC Class Codes: G06F 40/189 Automatic justification
• CPC Class Codes: G06F 40/197 Version control for software G06F8/71

Abstract

An efficient method for parsing HTML pages identifies pages containing a mix of static and dynamic content. The pages are parsed to form abstract syntax trees (ASTs), which are then cached along with the pages. When a later version of a page is retrieved, it is compared against the cached version, and only those portions of the AST that contain different content are reparsed.

Claims

1. A computer-implemented method for efficiently parsing received data files, comprising:

receiving, by a virtual browser executing on a server that is intermediary to a plurality of clients and a plurality of web servers, a data file from one of the plurality of web servers, responsive to a request by one of the plurality of clients;

determining that the received data file comprises an object that is not cached on the server;

determining whether the object is currently being tracked;

retrieving a previously stored version of the data file and a syntax tree comprising nodes and tokens representing data within the previously stored version of the data file, the syntax tree including at least one static node;

comparing the previously stored version of the data file with the received data file and identifying non-matching content in the received data file;

parsing only the non-matching content of the received data file;

updating the syntax tree by replacing the at least one static node of the syntax tree with a new token;

creating a mapping from the new token to a subtree in the syntax tree; and

storing the updated syntax tree.

2. The computer-implemented method of claim 1 wherein the data file is a web page.

3. The computer-implemented method of claim 1 wherein the data file is an HTML file.

4. A method for efficiently parsing web pages, comprising:

receiving, by a virtual browser executing on a server that is intermediary to a plurality of a clients and a plurality of web servers, an HTML page from one of the plurality of web servers, responsive to a request by one of the plurality of clients;

determining that the received HTML page comprises an object that is not cached on the device server;

determining whether the object is currently being tracked;

retrieving a previously cached version of the HTML page and a syntax tree comprising nodes and tokens representing data within the previously cached version of the HTML page, the syntax tree including at least one static node;

comparing the previously cached version of the HTML page with the received HTML page and identifying non-matching content in the received HTML page;

parsing only the non-matching content in the received HTML page;

updating the syntax tree by replacing the at least one static node of the syntax tree with a new token;

creating a mapping from the new token to a subtree in the syntax tree; and

storing the updated syntax tree and a most recent version of the HTML page.

5. A method for efficiently parsing HTML pages, comprising:

receiving, by a virtual browser executing on a server that is intermediary to a plurality of a clients and a plurality of web servers, an HTML page from one of the plurality of web servers, responsive to a request by one of the plurality of clients;

responsive to a determination that a previously cached version of the HTML page exists;

retrieving the previously cached version of the HTML page and a first syntax tree comprising nodes and tokens representing data within the previously cached version of the HTML page, the syntax tree including at least one static node;

comparing the previously cached version of the HTML page with the received HTML page and identifying non-matching content in the received HTML page;

parsing only the non-matching content in the received HTML page;

updating the syntax tree by replacing the at least one static node of the syntax tree with a new token; and

creating a mapping from the new token to a subtree in the syntax tree;

responsive to a determination that a previously cached version of the HTML page does not exist;

parsing the received HTML page and building a syntax tree comprising nodes and tokens representing content of the received data file, the syntax tree containing at only static nodes; and

storing the syntax tree and the received HTML page in a cache.

6. A method for efficiently parsing received data files, comprising:

receiving, by a virtual browser executing on a server that is intermediary to a plurality of clients and a plurality of web servers, a data file from one of the plurality of web servers, responsive to a request by one of the plurality of clients;

determining that the received data file comprises an object that is not cached on the server;

determining whether the object is currently being tracked;

retrieving a previously stored version of the data file and a syntax tree comprising nodes and tokens representing data within the previously stored version of the data file, the syntax tree including at least one static node;

comparing the previously stored version of the data file with the received data file and identifying non-matching content present only in the received data file;

parsing only the non-matching content of the first data file;

updating the syntax tree by replacing the at least one static node of the syntax tree with a new token;

mapping the new token to a subtree in the syntax tree; and

storing the updated syntax tree.

7. The method of claim 6, further comprising:

responsive to identifying non-matching content present only in the received file;

adding the new token to the syntax tree.

8. A system for efficiently parsing input data from a plurality of content servers, comprising:

a server that is intermediary to a plurality of clients and a plurality of web servers, wherein the server performs the following functions;

receiving a data file from one of the plurality of web servers, responsive to a request by one of the plurality of clients;

determining that the received data file comprises an object that is not cached on the server;

determining whether the object is currently being tracked;

retrieving a previously stored version of the data file and a syntax tree comprising nodes and tokens representing data within the previously stored version of the data file, the syntax tree including at least one static node;

comparing the previously stored version of the data file with the received data file and identifying non-matching content in the received data file;

parsing only the non-matching content of the received data file;

updating the syntax tree by replacing the at least one static node of the syntax tree with a new token;

creating a mapping from the new token to a subtree in the syntax tree; and

storing the updated syntax tree.

9. A system for efficiently parsing received data files transmitted between a client and a server, the system comprising:

a server that is intermediary to a plurality of clients and a plurality of web servers, wherein the server performs the following functions;

receiving a data file from one of the plurality of web servers, responsive to a request by one of the plurality of clients;

determining that the received data file comprises an object that is not cached on the server;

determining whether the object is currently being tracked;

retrieving a previously stored version of the data file and a syntax tree comprising nodes and tokens representing data within the previously stored version of the data file, the syntax tree including at least one static node;

comparing the previously stored version of the data file with the received data file and identifying non-matching content in the received data file;

parsing only the non-matching content of the received data file;

updating the syntax tree by replacing the at least one static node of the syntax tree with a new token;

creating a mapping from the new token to a subtree in the syntax tree; and

storing the updated syntax tree.