Session tokens

A session token is an 8-byte binary value that uniquely identifies a connection between XCICS as an HTTP client, and an HTTP server. The use of a session token for each connection means that XCICS Web support can manage multiple connections to servers by different tasks, and also means that an application program can control more than one connection.

A connection begins in response to a WEB OPEN command issued by a user application program. The session token is returned on successful completion of the WEB OPEN command, and used on all the EXEC CICS WEB commands issued by the application program concerning that connection.

Using the connection, the user application program can make HTTP client requests to the server, and receive responses from it. The connection can persist for more than one exchange of a request and a response, until either the application program or the server chooses to terminate the connection.

If the server terminates the connection, the application program cannot send any further requests using that connection, but it can read the response that the server sent before it terminated the connection. The session token remains valid for use on commands to access that data, until the application issues the WEB CLOSE command. After the WEB CLOSE command is issued, the session token that applies to the connection is no longer valid. If the application program does not issue a WEB CLOSE command, the connection is closed at end of task.

The maximum number of open client connections, each represented by a session token, that can be present simultaneously in a XCICS region is 32768.