CICS® Web support includes modules used for:
DFHWBIP initializes the Web environment at CICS startup.
DFHWBXN is the Web attach processing module. It is the initial program invoked for transaction CWXN (or an alias of CWXN), which is attached for a new sockets connection received on a port associated with a TCPIPSERVICE definition with PROTOCOL(HTTP). It is also invoked for transaction CWXU (or alias), which is attached when the TCPIPSERVICE definition specifies PROTOCOL(USER). It calls the Web domain WBSR gate to process the incoming data.
DFHWBAAX is the default analyzer program for a TCPIPSERVICE definition that specifies PROTOCOL(HTTP). It does not carry out further processing when a matching URIMAP definition has been found for the request, even if the URIMAP specifies ANALYZER(YES). It tests for the presence of a URIMAP definition, and if the result is positive, returns without performing any analysis on the request URL. This means that the settings specified in the URIMAP definition for the alias transaction, converter program and application program are automatically accepted and used to determine subsequent processing stages.
If no matching URIMAP definition is found, DFHWBAAX gives control to the user-replaceable Web error application program DFHWBERX to produce an error response. This is achieved by setting DFHWBERX as the application program to handle the request.
An alternative analyzer program that has been specified on the TCPIPSERVICE definition, such as the CICS-supplied sample analyzer program DFHWBADX, might carry out analysis on the request and specify alternative settings for the alias transaction, converter program and application program.
When the TCPIPSERVICE definition specifies PROTOCOL(USER), an analyzer program is always required to determine processing for requests (which are treated as non-HTTP requests). DFHWBAAX is not suitable for PROTOCOL(USER). The CICS-supplied sample analyzer program DFHWBADX or a customized analyzer program must be used instead. URIMAP definitions are not used with PROTOCOL(USER).
DFHWBA is the alias program. An alias transaction is started by Web attach processing for each request received from TCP/IP. The transaction ID can be selected by a URIMAP definition or an analyzer program, and the default is CWBA. For CICS Web support, DFHWBA calls the user application program that is specified to process the request. This application program could be specified in a URIMAP definition, or by an analyzer program or converter program. For the CICS business logic interface, DFHWBA calls the CICS business logic interface program.
A Web error program is used to provide an error response to the Web client when a request error or an abend occurs in the CICS Web support process. DFHWBEP is called when CICS detects an error in request processing. Alternatively, in situations where the error can be identified by the active program, the Web error application program DFHWBERX can be specified to send the error response. DFHWBERX is used when the CICS-supplied default analyzer DFHWBAAX is specified as the analyzer program on the TCPIPSERVICE definition, and no matching URIMAP definition is found for a request.
DFHWBEP is called in the following situations:
If a sockets send or receive error occurs, the socket is closed and no response is sent to the Web client.
DFHWBEP is user-replaceable. It uses a COMMAREA-based interface, where information about the error situation is passed to the program in a COMMAREA, and a complete HTTP response is created as a buffer of data. (DFHWBERX uses the EXEC CICS commands to obtain information about the Web client's request and create and send the error response.)
After the error response has been sent, the socket is usually left open for possible further requests from the Web client, until timeout is reached. The exception is when a 501 (Method Not Implemented) response is sent, in which case the socket is closed.
DFHWBCL is the HTTP client processing module. It is called by the command interface DFHEIWB (when EXEC CICS WEB commands with the SESSTOKEN option are used in application programs), and the COMMAREA interface DFHWBCLI, to handle outbound HTTP functions, such as opening a session and writing a request to the socket.
DFHWBBLI is the CICS business logic interface program. The interface to the CICS business logic interface program is described in CICS Internet Guide.
The CICS business logic interface program is called by DFHWBA. It calls the Decode function of a converter program, a CICS application program, or the Encode function of a converter program, according to what is specified in its parameter list, and passes the data back to the caller.
DFHWBA1 is the business logic compatibility interface program. In earlier releases, it was the business logic interface program, but it is now a compatibility layer on DFHWBBLI. It accepts data from an old-format business logic interface parameter list, copies it to the new format parameter list, then links to DFHWBBLI.
The modules used by CICS Web support for handling 3270 display applications (sometimes referred to as the CICS Web bridge) are:
DFHWBUN provides an unescaping function for data which has been transmitted to CICS in its escaped form, but which the application needs to manipulate in its unescaped form.
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