System and method to refresh proxy cache server objects
First Claim
1. A method for refreshing objects stored in a Proxy cache server, with new versions of the objects stored by Web content servers communicating by messages through a network with the Proxy cache server, the Proxy cache server and the Web content servers supporting a standard request for one object and a standard refresh request for one object based on a last modified date, said method comprising the steps of:
- storing, in the Proxy cache server, a cache index table containing, for each object stored, an identifier of the object, a file name of the object in the Proxy cache server, a network address of a Web content server owning the object, an object validity expiration date and a signature identifying a content of the object;
reading the cache index table, and selecting one object for which the object validity expiration date is exhausted;
sending from the Proxy cache server to the Web content server owning the selected object, a Refresh_request command in a first payload of a first message, an argument of the first message being the object identifier and an object signature;
receiving from the Web content server a Refresh_response command in a second payload of a second message, arguments of the second message being the object identifier and, if the signature of the object stored in the Web content server is different from the signature in the Refresh_request command, the object stored in the Web content server, a new object signature and a new expiration date;
updating, in the Proxy cache server, the cache index table with the new object signature and the new expiration date of the object and updating the object file name with the object stored in the Web content server;
sending from the Proxy cache server a standard request for the one object;
receiving a third message back from the Web content server containing the object requested and the last modified date of the object;
if the third message further contains the object signature and an indication that the Web content server supports a Refresh_request command, updating, in the Proxy cache server, a Web content server table containing, for each Web content server having already sent to the Proxy cache server one object, the network address of the Web content server and the indication that the Web content server supports the Refresh_request command;
if the third message does not further contain the object signature and the indication that the Web content server supports the Refresh_request command, updating in the Proxy cache server, the Web content server table with another indication that the Web content server does not support the Refresh_request command and updating the cache index table with the last modified date of the object;
updating, in the cache index table, the object file name containing the object stored in the Web content server and the object expiration date.
1 Assignment
0 Petitions
Accused Products
Abstract
A method and computing systems for refreshing objects stored by a Proxy cache server from Web content servers. The refresh is requested by the Proxy cache server only if the expiration date attached to a stored object has expired. The refresh of one object is requested by the Proxy cache server to the Web content server upon a request from the browser of a client device. Additionally, the Proxy cache server can send a Refresh_request command to the Web content servers applying to a list of objects for which the expiration date has expired. The refreshed objects are not sent by the Web content server if the last modified date has changed but rather if, and only if, the object content, identified by a signature, has been changed. This method and system have the advantage of offloading the computing resources involved for data transfer through the network connecting the servers.
87 Citations
11 Claims
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1. A method for refreshing objects stored in a Proxy cache server, with new versions of the objects stored by Web content servers communicating by messages through a network with the Proxy cache server, the Proxy cache server and the Web content servers supporting a standard request for one object and a standard refresh request for one object based on a last modified date, said method comprising the steps of:
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storing, in the Proxy cache server, a cache index table containing, for each object stored, an identifier of the object, a file name of the object in the Proxy cache server, a network address of a Web content server owning the object, an object validity expiration date and a signature identifying a content of the object; reading the cache index table, and selecting one object for which the object validity expiration date is exhausted; sending from the Proxy cache server to the Web content server owning the selected object, a Refresh_request command in a first payload of a first message, an argument of the first message being the object identifier and an object signature; receiving from the Web content server a Refresh_response command in a second payload of a second message, arguments of the second message being the object identifier and, if the signature of the object stored in the Web content server is different from the signature in the Refresh_request command, the object stored in the Web content server, a new object signature and a new expiration date; updating, in the Proxy cache server, the cache index table with the new object signature and the new expiration date of the object and updating the object file name with the object stored in the Web content server; sending from the Proxy cache server a standard request for the one object; receiving a third message back from the Web content server containing the object requested and the last modified date of the object; if the third message further contains the object signature and an indication that the Web content server supports a Refresh_request command, updating, in the Proxy cache server, a Web content server table containing, for each Web content server having already sent to the Proxy cache server one object, the network address of the Web content server and the indication that the Web content server supports the Refresh_request command; if the third message does not further contain the object signature and the indication that the Web content server supports the Refresh_request command, updating in the Proxy cache server, the Web content server table with another indication that the Web content server does not support the Refresh_request command and updating the cache index table with the last modified date of the object; updating, in the cache index table, the object file name containing the object stored in the Web content server and the object expiration date. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A computer program stored on a computer readable medium comprising programming code instructions which when executed, enables a computer system to implement a method for refreshing objects stored in a Proxy cache server, with new versions of the objects stored by Web content servers communicating with messages through a network with the Proxy cache server, the Proxy cache server and the Web content servers supporting a standard request for one object and a standard refresh request for one object based on a last modified date, said programming code instructions comprising:
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storing, in the Proxy cache server, a cache index table containing, for each object stored, an identifier of the object, a file name of the object in the Proxy cache server, a network address of a Web content server owning the object, an object validity expiration date and a signature identifying a content of the object; reading the cache index table, and selecting one object for which the object validity expiration date is exhausted; sending from the Proxy cache server to the Web content server owning the selected object, a Refresh_request command in a first payload of a first message, an argument of the first message being the object identifier and an object signature; receiving from the Web content server a Refresh_response command in a second payload of a second message, arguments of the second message being the object identifier and, if the signature of the object stored in the Web content server is different from the signature in the Refresh_request command, the object stored in the Web content server, a new object signature and a new expiration date; updating, in the Proxy cache server, the cache index table with the new object signature and the new expiration date of the object and updating the object file name with the object stored in the Web content server; sending from the Proxy cache server a standard request for the one object; receiving a third message back from the Web content server containing the object requested and the last modified date of the object; if the third message further contains the object signature and an indication that the Web content server supports a Refresh_request command, updating, in the Proxy cache server, a Web content server table containing, for each Web content server having already sent to the Proxy cache server one object, the network address of the Web content server and the indication that the Web content server supports the Refresh_request command; if the third message does not further contain the object signature and the indication that the Web content server supports the Refresh_request command, updating in the Proxy cache server, the Web content server table with another indication that the Web content server does not support the Refresh_request command and updating the cache index table with the last modified date of the object; updating, in the cache index table, the object file name containing the object stored in the Web content server and the object expiration date. - View Dependent Claims (11)
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Specification