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Background documentationModifications of HTTP Requests Locate this document in the navigation structure

 

On the way from the client (browser) to the server (application server in an SAP system) an HTTP request passes several stations. In a standard scenario the request goes to an SAP Web Dispatcher, which is the entry point into the demilitarized zone (DMZ) of the network. It filters the requests and distributes them to the connected application servers of the SAP system.

It is often best to execute certain operations in the HTTP server already, rather than waiting to do them in the back end (application server). This involves checking the syntax and semantics of the request, filtering URLS, redirects, caching, and hiding the implementation details in the URL.

The following manipulations are possible:

  • Manipulation of HTTP header fields in a request (append, remove, change)

  • Filtering requests (by creating an error page)

  • Redirecting requests to another page

  • Manipulation of URL values (path and query string)

These functions are implemented in a subhandler (HTTP request manipulation handler), which contains both the Web Dispatcher and the ICM. The section Defining Modification Actions describes how you can configure the Web Dispatcher/ICM.

The sequence of the individual operations is as follows:

  1. All compatibility operations. In older releases special operations could be executed in the HTTP handler. These operations are now carried out centrally in the modification handler.

  2. All header field manipulations (with and without conditions) are executed in the order they appear in the action file.

  3. URL manipulations (with and without conditions) are executed in the order they appear in the action file.