Persistant client state in a hypertext transfer protocol based client-server system

Abstract

A method and apparatus for transferring state information between a server computer system and a client computer system. In one embodiment of the method, an http client requests a file, such as an HTML document, on an http server, and the http server transmits the file to the http client. In addition, the http server transmits a state object, which describes certain state information, to the http client. The http client stores the state object, and will typically send the state object back to the http server when making later requests for files on the http server. In a typical embodiment, the state object includes a domain attribute which specifies a domain or network address, and the state object is transmitted from the http client to a server only when the http client makes an http request to the server and the server is within the domain. In one embodiment, the apparatus includes a processor and memory and a computer readable medium which stores program instructions. In the case of the client system, the instructions specify operations such as receiving and storing the state information; in the case of the server system, the instructions specify operations such as sending the state information to a client system.

1 . A method for subscribing to an on-line information service, said method comprising the steps of: 
 requesting a first information service from an http server; and    transmitting a state object from a client computer system to said http server, said state object being stored on said client system and specifying user information to said http server.    
     
     
         2 . A method as in  claim 1  wherein said sate object specifies user identification information and billing information.  
     
     
         3 . A method as in  claim 1  further comprising: 
 requesting a second information service from said http server or an alternative http server;    transmitting said object to said http server or said alternative http server.    
     
     
         4 . A method as in  claim 3  wherein a user of said on-line information service browses from said first information service to said second information service without having to enter user information.  
     
     
         5 . A method of  claim 3  wherein said user information comprises subscription information required by a first publisher of said first information service.  
     
     
         6 . A method as in  claim 5  wherein said user information comprises subscription information required by a second publisher of said second information service.  
     
     
         7 . A method for subscribing to an on-line information service, said method comprising: 
 requesting a first document from a server; and    transmitting a state object from a client computer system to said server, said state object being stored on said client system and specifying user information to said server.    
     
     
         8 . The method of  claim 7 , wherein said state object specifies user identification information and billing information.  
     
     
         9 . The method of  claim 7 , further comprising: 
 requesting a second document from said server or an alternative server; transmitting said object to said server or said alternative server.    
     
     
         10 . The method of  claim 9 , wherein a user of said on-line information service browses from said first document to said second document without having to enter user information.  
     
     
         11 . The method of  claim 9 , wherein said user information comprises subscription information required by a first publisher of said first document.  
     
     
         12 . The method of  claim 12 , wherein said user information comprises subscription information required by a second publisher of said second document.  
     
     
         13 . A method for a retaining persistent client state information using state object cookies, said method comprising: 
 requesting a document from a server; and    transmitting a state object from said server to a client computer system, said state object being stored on said client computer system and specifying client state information.    
     
     
         14 . The method of  claim 13 , wherein said transmitting step further comprises: 
 sending an HTML document from said server with said state object in said HTML document's header in response to said document request.    
     
     
         15 . The method of  claim 14 , wherein said HTML document's header contains a plurality of state objects.  
     
     
         16 . The method of  claim 14 , wherein said HTML document is displayed to a user by a Web browser on said client computer system.  
     
     
         17 . The method of  claim 13 , further comprising: 
 transmitting a state object from said client computer system to said server along with a document request from said server.    
     
     
         18 . The method of  claim 17 , wherein said client computer system sends a stored state object to a server when said stored state object pertains to said server and said requested document.  
     
     
         19 . The method of  claim 13 , wherein said client computer system stores a plurality of state objects.  
     
     
         20 . The method of  claim 13 , wherein a state object specifies a server or domain name.  
     
     
         21 . The method of  claim 13 , wherein a state object specifies an expiration date and/or time.  
     
     
         22 . The method of  claim 21 , wherein said client computer system purges expired state objects.  
     
     
         23 . The method of  claim 13 , wherein a state object specifies information pertaining to a product selected by a user.  
     
     
         24 . The method of  claim 13 , wherein if said client computer system receives a state object with the same identification attributes as a state object that is already stored on said client computer system, then said client computer system discards the stored state object and stores the received state object.  
     
     
         25 . The method of  claim 13 , wherein a state object specifies if it is a secure state object, and wherein if a state object is secure, then said client computer system only transmits said secure state object over a secure communication channel to said server.