Description:
------------
The following SAPI that handle Apache are doing the content length setting wrong:

apache, apache2handler, apache2filter

The problems when you do:

  header("Content-Length: 20");

the SAPI module would just set the header doing a table set on r->headers_out, but not update r->clength.  Instead of doing a table set it should be calling ap_set_content_length, which sets clength and does the table set for you.

I found this in Apache 2.x because we have a filter that appends data to the end of the content.  It uses r->clength and updates with the additionally data value, but it doesn't work correctly if you use the above header PHP call.

The following patch fixes the problem:

http://www.brianfrance.com/software/php/sapi_content_length.txt

Let me know if you have any questions.