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DataPower firmware version 6.0 changes Content-Length header to chunked

Technote (FAQ)


Question

I upgraded DataPower from V5 to V6. Now, when my client application submits HTTP/1.1 requests via DataPower, the responses returned to the client no longer include the Content-Length header. What changed between the versions?

Cause

A client that is fully compliant to the HTTP/1.1 specification must be able to handle the Transfer-Encoding header.

Answer

Up to 5.0.0 firmware, when HTTP/1.1 is used on the front end, DataPower selected the response length encoding (Chunked or Content-Length) using rather complex criteria that were not always optimal, specifically preventing streaming in some cases.

To resolve the above defect, starting with 6.0.0, DataPower always uses Transfer-Encoding (chunked) instead of Content-Length header when responding to HTTP/1.1 request.

This is compliant with IETF RFC 7230 section 4.1 about Chunked Transfer Coding that has the following statement:


    "A recipient MUST be able to parse and decode the chunked transfer coding."

All DataPower firmware releases generate responses with Content-Length format when using HTTP/1.0 protocol.

Document information

More support for: WebSphere DataPower Integration Appliance XI52

Software version: 6.0.0

Operating system(s): Firmware

Reference #: 1690276

Modified date: 21 November 2014