HTTP client requests from a CICS application

CICS® can act as an HTTP client, and communicate with an HTTP server on the Internet. A user-written application program sends requests through CICS to the HTTP server, and receives the responses from it.

In CICS Transaction Server for z/OS®, Version 3 Release 1, the facility for CICS to act as an HTTP client is fully integrated into CICS Web support. You could use this facility in your user-written application programs to enable the applications to:

Note that the HTTP client facility of CICS Web support is not designed for use as a browser. User application programs can make requests for individual, known resources that are available from a server, but they would not be expected to browse the Internet generally. The range of responses that you might receive from a server, and the actions that you need to take to handle them, should relate only to your preselected resources, plus the error responses that might be associated with those resources and with the type of requests you are making.

HTTP request and response processing for CICS as an HTTP client explains the processing structure for CICS as an HTTP client. Before writing an application program that makes an HTTP client request, make sure you understand the processing stages for these requests, because most of the stages are initiated by the application program itself.

Several CICS Web support facilities are used when CICS is an HTTP client: TCPIPSERVICE resource definitions, which are used for CICS as an HTTP server, do not apply to CICS as an HTTP client, and you do not need to create these to make HTTP client requests.