4.7.2.9. Stacking

HTTP supports stacking proxies for both request and response entities (e.g.: data bodies). This is controlled by the request_stack and response_stack attribute hashes. See also Section 2.3.1, Proxy stacking.

There are two stacking modes available: HTTP_STK_DATA sends only the data portion to the downstream proxy, while HTTP_STK_MIME also sends all header information to make it possible to process the data body as a MIME envelope. Please note that while it is possible to change the data part in the stacked proxy, it is not possible to change the MIME headers - they can be modified only by the HTTP proxy. The possible parameters are listed in the following tables.

ActionDescription
HTTP_STK_NONE No additional proxy is stacked into the HTTP proxy.
HTTP_STK_DATA The data part of the HTTP traffic is passed to the specified stacked proxy.
HTTP_STK_MIME The data part including header information of the HTTP traffic is passed to the specified stacked proxy.

Table 4.13.  Constants for proxy stacking

Please note that stacking is skipped altogether if there is no body in the message.