Meta-data based method for local cache utilization

• US 8,291,081 B2
• Filed: 07/19/2011
• Issued: 10/16/2012
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: SlipStream Data Incorporated (Blackberry Limited)
• Inventors: Singh, Ajit, Ahmed, Salmaan Syed
• Primary Examiner(s): TANG, KAREN C
• Application Number:
  US13/186,157
• Publication Number:
  US 20120016931A1
• Time in Patent Office: 455 Days
• Field of Search: 709/226, 709/223, 709/225, 709/217
• US Class Current: 709/226
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/2876 Pairs of inter-processing entities at each side of the network, e.g. split proxies
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 67/5682 Policies or rules for updating, deleting or replacing the stored data
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A system and method for caching data and verifying cached data using a client-server model and meta-data. In particular, a client proxy and a server proxy are in communication with each other and with the client and the server, respectively; client proxy meta-data and server proxy meta-data related to the data cached by the client proxy and server proxy, respectively, are calculated and communicated between the client proxy and the server proxy; and the client proxy meta-data and the server proxy meta-data are compared to determine a cache hit or miss.

Claims

1. A method for optimizing the transmission of data from a server located on a server computer to a client located on a client computer the method comprising steps for:

a) upon a client request for response data hosted by the server located on a server computer to a client proxy, determining if a prior version of said response data exists in a client proxy cache, if so computing client proxy meta-data from said prior version of said response data to identify said prior version;

b) if at step a) said prior version of said response data does not exist in said client proxy cache, sending a request for said response data to said server proxy;

c) upon computing client proxy meta-data in step a), determining if said prior version of said response data is current by comparing said client proxy meta-data with server proxy meta-data computed from the response data requested, if said prior version of said response data is current, informing said client proxy of this, if not then fetching the current response data from said server, returning current response data and computing new server proxy meta-data from said current response data to identify a current server version;

d) upon receipt of a request from step b), fetching current response data from said server and computing server proxy meta-data from said current response data to identify the current server version;

e) after fetching the current response data in step d), computing said client proxy meta-data from said current response data to identify a current client version; and

f) based on the preceding steps, forwarding said prior version of said response data or said current response data from said client proxy to said client located on the client computer.

2. The method of claim 1, wherein the server is an HTTP server having a URL and the meta-data comprises meta-data other than the last-modified time/date and/or the expiration time/date as specified in the response data fetched previously from the HTTP server for the same URL.

3. The method of claim 2, wherein said client proxy meta-data and said server proxy meta-data comprise at least a hash value.

4. The method of claim 1, wherein the client proxy and the server proxy store meta-data indexed or keyed to a requested URL.

5. The method of claim 1, wherein the response data is indicated as uncacheable.

6. The method of claim 5, wherein the response data is indicated as uncacheable by HTTP headers selected from the group of “

Cache-Control;

private” and

“

Cache-Control;

no-cache”

.

7. A method for ascertaining the validity of cached response data on a HTTP client located on a computer for a given URL, the method comprising steps for:

a) receiving at a client proxy, a client request for response data hosted by an HTTP server located on a server computer;

b) determining if a client proxy version of the response data exists in a client proxy cache;

c) sending a request comprising client proxy meta-data computed from the client proxy version of the response data to a server proxy if it is determined in step b) that the client proxy version of the response data exists in the client proxy cache;

d) sending a request to the server proxy for the response data if it is determined at step b) that the client proxy version of the response data does not exist in the client proxy cache;

e) if a server proxy version of the requested response data is not found, receiving current response data retrieved from the HTTP server at the server proxy and computing server proxy meta-data from the retrieved current response data;

f) receiving a notification from a processor that the client proxy version of the response data is current when a comparison is made, by the processor, of the client proxy meta-data and the server proxy meta-data, computed from the server proxy version of the response data, and the processor determines that the client proxy version of the response data is current, otherwise, receiving the retrieved current response data from the server proxy at the client proxy;

g) computing client proxy meta-data from the received current response data independently of the server proxy meta-data; and

h) forwarding the prior version of the data or the retrieved current response data from the client proxy to the client located on the client computer.

8. The method of claim 7, wherein the meta-data is other than last-modified time/date and/or expiration time/date as specified in the response data fetched previously from the HTTP server for the same URL.

9. The method of claim 8, wherein the client proxy meta-data and the server proxy meta-data comprise at least a hash value.