Meta-data based method for local cache utilization

• US 20050138176A1
• Filed: 12/22/2004
• Published: 06/23/2005
• 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
• Granted Patent: US 8,010,670 B2
• Time in Patent Office: Days
• 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 system for caching data using a client-server model, the system comprising:

a) a client proxy and a server proxy in communication with each other and with the client and the server, respectively;

b) means for calculating client proxy meta-data and server proxy meta-data related to the data cached by the client proxy and server proxy, respectively;

c) means for communicating said meta-data between the client proxy and the server proxy; and

d) means for comparing the client proxy meta-data and the server proxy meta-data to determine a cache hit or miss.

2. The system of claim 1, wherein said means for calculating meta-data calculates one or more hash values based on the content of the cached data.

3. A method for optimizing the transmission of data from a server to a client said method comprising the steps of:

a) upon a client request for data to a client proxy, determining if a prior version of said data exists in a client proxy cache, if so forwarding a request containing client proxy meta-data describing said prior version of said data to a server proxy;

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

c) upon receipt of a request from step a) said server proxy determining if said prior version of said data is current based on comparing said client proxy meta-data with server proxy meta-data describing the data requested, if said prior version of said data is current, informing said client proxy of this, if not then fetching the current data from the said server, returning current data and updating server proxy meta-data;

d) upon receipt of a request from step b) fetching current data from said server, updating server proxy meta-data, and sending said current data to said client proxy;

e) updating said client proxy meta-data when said client proxy receives current data from said server proxy; and

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

4. The method of claim 3, wherein 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.

5. The method of claim 3, wherein the client proxy and the server proxy store meta-data indexed (or keyed) to the requested URL.

6. The method of claim 3, wherein the data is indicated as “

uncacheable”

by the administrators of that HTTP server data.

7. The method of claim 6, wherein the data is indicated as “

Cache_Control;

private”

or as “

Cache-Control;

no-cache”

.

8. A method for ascertaining the validity of cached data on a HTTP client for a given URL using meta-data derived from response data previously fetched from the HTTP server for the same URL.

9. The method of claim 8, 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.