XML request processing for passthrough

Passthrough request processing is supported by Link3270 server adapters only. At run time, XML request processing for passthrough is initiated from the passthrough stub program (DFHMADPP).

When the passthrough stub program DFHMADPP determines that the request message header is in XML, the following processing occurs:
  1. DFHMADPP issues a call to the XML to COBOL Converter program DFHMAXMI.

    DFHMAXMI parses the message header (DFHMAH) and the passthrough message header (DFHMAH2).

  2. Instead of using a custom XML parser to parse the application data, the passthrough XML converter program DFHMAXPI is always used to parse the application data in a passthrough request.
    Note: Unlike XML request and response processing for non-passthrough, the Application Data XML Converter program is provided in the runtime environment. XML request and response processing.

    The passthrough XML converter program DFHMAXPI parses the inbound XML passthrough request message (the portion of the XML request message following the header structures, DFHMAH and DFHMAH2), converting the screen header, map header, and screen data from XML to the fixed format screen header, map header, and CICS® ADS structure.

    DFHMAXPI references the Link3270 Repository file to create the ADS structure required by the Link3270 bridge mechanism. An XML message format is published to which the service requestor must conform in order to create valid XML request message for Passthrough.

  3. DFHMAXPI saves the XML declaration portion of the XML and passes it back to the passthrough DPL Stub program.

    This information is used for XML response processing.

Figure 1. XML Request processing - passthrough
Diagram shows the processing that is performed by the Passthrough DPL Stub program.