METHODS AND SYSTEMS FOR IMPLEMENTING A CACHE MODEL IN A PREFETCHING SYSTEM

• US 20090100228A1
• Filed: 10/15/2008
• Published: 04/16/2009
• Est. Priority Date: 10/15/2007
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Sebastian, William B., Lepeska, Peter
• Granted Patent: US 9,460,229 B2
• Time in Patent Office: Days
• US Class Current: 711/125
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 67/5681 Pre-fetching or pre-delivering data based on network characteristics

Abstract

The present invention relates to systems and methods of enhancing prefetch operations. The method includes fetching an object from a page on a web server. The method further includes storing, at a proxy server, caching instructions for the fetched object. The proxy server is connected with the client and the object is cached at the client. Furthermore, the method includes identifying a prefetchable reference to the fetched object in a subsequent web page and using the caching instructions stored on the proxy server to determine if a fresh copy of the object will be requested by the client. Further, the method includes, based on the determination that the object will be requested, sending a prefetch request for the object using an If-Modified-Since directive, and transmitting a response to the If-Modified-Since directive prefetch request to a proxy client.

Claims

1. A method of enhancing prefetch operations, the method comprising:

fetching, on behalf of a client, at least one object from a page on a web server;

storing, at a proxy server, caching instructions for the at least one fetched object, wherein the proxy server is connected with the client and the at least one object is cached at the client;

identifying a prefetchable reference to the at least one fetched object in a subsequent web page;

using the caching instructions stored on the proxy server to determine if a fresh copy of the at least one object will be requested by the client;

based on the determination that a fresh copy of the at least one object will be requested, sending a prefetch request for the object using an If-Modified-Since directive; and

transmitting a response to the If-Modified-Since directive prefetch request to a proxy client.

2. The method of enhancing prefetch operations of claim 1, further comprising based on the determination that a fresh copy of the at least one object will not be requested by the client, not prefetching an updated version of the at least one object from the web server.

3. The method of enhancing prefetch operations of claim 1, wherein the caching instructions for the at least one object is stored to a persistent storage device.

4. The method of enhancing prefetch operations of claim 3, further comprising accessing the persistent storage device when responding to prefetch requests.

5. The method enhancing prefetch operations of claim 1, wherein the If-Modified-Since directive prefetch request is compressed.

6. The method of enhancing prefetch operations of claim 1, wherein the caching instructions include a checksum value for the at least one object.

7. The method of enhancing prefetch operations of claim 6, further comprising comparing the checksum value associated with the at least one object with a current checksum received from the web server to determine if the at least one object has changed since it was prefetched.

8. The method of enhancing prefetch operations of claim 7, further comprising, in response to the checksum values not matching, prefetching the updated at least one object from the web server.

9. The method of enhancing prefetch operations of claim 8, wherein the checksum values are stored in an entity tag.

10. The method of enhancing prefetch operations of claim 1, further comprising maintaining a list of last modified date entries associated with each prefetched object.

11. The method of enhancing prefetch operations of claim 10, further comprising using the list of last modified date entries to determine if an object should be prefetched.

12. The method of enhancing prefetch operations of claim 1, further comprising maintaining a list of caching instructions for each object prefetched on behalf of the client.

13. The method of enhancing prefetch operations of claim 12, wherein the caching instructions comprise at least one of:

a last modified date, an expiration date, caching permitted flag, and an entity tag.

14. The method of enhancing prefetch operations of claim 1, further comprising storing cache model entries for each object.

15. The method of enhancing prefetch operations of claim 14, further comprising updating the cache model entries with modified dates received from the prefetch response.

16. A system for enhancing prefetch operations, the system comprising:

a client including a proxy client, wherein the proxy client is configured to transmit object requests;

a proxy server connected with the client via the proxy client, the proxy server configured to fetch, on behalf of the client, at least one object from a webpage, store caching instructions for the at least one fetched object, identify a prefetchable reference to the at least one fetched object in a subsequent web page, use the caching instructions to determine if a fresh copy of the at least one object will be requested by the client, and based on the determination that a fresh copy of the at least one object will be requested, send a prefetch request for the object using a If-Modified-Since directive; and

a web server connected with the proxy server, the web server configured to transmit a response to the If-Modified-Since directive prefetch request.

17. The system for enhancing prefetch operations of claim 16, wherein the proxy server is further configured to based on the determination that a fresh copy of the at least one object will not be requested by the client, not prefetch an updated version of the at least one object from the web server.

18. The system for enhancing prefetch operations of claim 16, wherein the proxy server comprises a storage device configured to store the caching instructions for the at least one object.

19. A machine-readable medium for enhancing prefetch operations, the machine-readable medium including sets of instructions stored thereon which, when executed by a machine, cause the machine to:

fetch, on behalf of a client, at least one object from a page on a web server;

store, at a proxy server, caching instructions for the at least one fetched object, wherein the proxy server is connected with the client and the at least one object is cached at the client;

identify a prefetchable reference to the at least one fetched object in a subsequent web page;

use the caching instructions stored on the proxy server to determine if a fresh copy of the at least one object will be requested by the client;

based on the determination that the at least one object will be requested, send a prefetch request for the object using an If-Modified-Since directive; and

transmit a response to the If-Modified-Since directive prefetch request to a proxy client.

20. The machine-readable medium for enhancing prefetching operations of claim 19, wherein the sets of instructions when further executed by the machine, cause the machine to, based on the determination that a fresh copy of the at least one object will not be requested by the client, not prefetch an updated version of the at least one object from the web server.

21. A method comprising:

establishing a network communications link between a client and a proxy server and between the proxy server and a web server;

maintaining, on the proxy server, a browser cache model for the client;

storing caching instructions in the browser cache model;

accessing the caching instructions stored on the proxy server to determine if a fresh copy of the at least one object will be requested by the client;

based on the determination that the at least one object will be requested, transmitting a prefetch request for the object using an If-Modified-Since directive; and

transmitting a response to the If-Modified-Since directive prefetch request to the client.