You can use CICS® Web support to process inbound TCP/IP client requests
which are not in the HTTP format. In CICS Transaction Server for z/OS®, Version 3 Release 1,
this facility is primarily intended to provide support for requests from user-written
clients that use nonstandard request formats. The processing that takes place
for requests, and the response that is provided, are defined by the user.
No specific support is provided for any formally defined protocols which are
used for client-server communication.
CICS Web
support only handles non-HTTP messages when CICS is the server. Non-HTTP requests cannot
be made by CICS as
a client. Client requests made through CICS Web support use the HTTP protocol.
When CICS Web
support facilities are used for handling non-HTTP requests:
- You can use TCPIPSERVICE resource definitions to control the ports on
which requests are received.
- You can use an analyzer program to assemble and parse requests, specify
code page conversion, and determine subsequent request processing. You can
code the analyzer program to parse requests in accordance with any request
format that you have defined, but note that this CICS facility does not provide specific
support for any particular protocol for which a formal definition exists.
- You can use either Web-aware application programs, or non-Web-aware applications
with a converter program, to provide responses to requests. Requests and responses
can be handled using certain elements of the EXEC CICS WEB programming interface, or passed
between CICS applications in a COMMAREA.
- The Web error program DFHWBEP provides an error response if an abend occurs
in the analyzer program, converter program, or user-written application program,
and also if the analyzer program and converter program cannot determine what application
program should be executed to service the request. The standard HTTP error
messages are used by default, but you can tailor these if required.
Some CICS Web
support facilities are not available for non-HTTP requests:
- Some of the facilities that help you interpret HTTP requests and construct
the responses are not available. For example, message headers cannot be accessed
separately.
- The enhancements introduced in CICS TS Version 3, including chunked transfer-coding,
are generally not available to non-HTTP requests.
- Persistent connections are not supported.
- URIMAP definitions are not used for non-HTTP requests.
The support that CICS Web support provides for non-HTTP messages is not
the same thing as the TCP/IP Sockets interface for CICS. The z/OS Communications Server IP CICS Sockets
interface provides an application programming interface to allow clients to
communicate directly with CICS application programs over TCP/IP. CICS Web support
is not involved with this process.
The CICS Sockets
interface is supplied with z/OS Communications Server, not with CICS. z/OS Communications
Server: IP CICS Sockets
Guide, SC31-8807, describes the CICS Sockets interface.