Converter programs: Constructing an HTTP response

Attention: This topic contains Product-sensitive Programming Interface and Associated Guidance Information.
The size and contents of the HTTP response that you construct in the converter program are governed by:
  • The number and length of the HTTP headers that you want to include in the response.
  • The length and contents of the HTML data that you want to send in your response.
In turn, these will be governed by the design of the user-written application program and the information that it returned in its COMMAREA.

The response must contain an HTTP version, status code, status text, any HTTP headers that are required, and the message body. The format of the response should be compliant with the HTTP protocol specification to which you are working (HTTP/1.0 or HTTP/1.1).

CICS® inserts some HTTP headers suitable for an HTTP/1.0 or HTTP/1.1 response, which are listed in HTTP header reference for CICS Web support. If the message in the COMMAREA already contains these headers, CICS does not replace them.

When you use a converter program with CICS Web support, you can:
  • Issue a GETMAIN command to obtain storage for the HTTP response.
  • Use storage acquired in an earlier stage of processing (such as the analyzer program) for the COMMAREA.
  • Construct the response in the COMMAREA returned by the application program.
The first word of the area used for the response must contain the length of the area (that is, the length of the HTTP response plus 4).

When you use a converter program with the CICS business logic interface, there are restrictions which may affect how you construct the response. For more information, see Offset mode and pointer mode.