HEAD requests in Apache 2.0

Here is something new in Apache 2.0 that's worth your attention.

Apache 2.0 automatically discards the response body for HEAD requests, 
so there is no more need to add logic to handle HEAD request unless you 
want to save the processing cycles. This was done in order to ensure 
that the response headers for GET/POST/... and HEAD will be the same.

Here is a quote from http_protocol.c:ap_http_header_filter

    /* [...]  The idea is that
     * we don't want to send out 0 Content-Lengths if it is a head request.
     * This happens when modules try to outsmart the server, and return
     * if they see a HEAD request.  Apache 1.3 handlers were supposed to
     * just return in that situation, and the core handled the HEAD.  In
     * 2.0, if a handler returns, then the core sends an EOS bucket down
     * the filter stack, and the content-length filter computes a C-L of
     * zero and that gets put in the headers, and we end up sending a
     * zero C-L to the client.  We can't just remove the C-L filter,
     * because well behaved 2.0 handlers will send their data down the 
stack,
     * and we will compute a real C-L for the head request. RBB
     */


__________________________________________________________________
Stas Bekman            JAm_pH ------> Just Another mod_perl Hacker
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