On Mon, 2 Jan 2006, Graham Dumpleton (JIRA) wrote:
In addressing MODPYTHON-71, mod_python.publisher code was changed to read: if req.method!='HEAD': req.write(result)This change should not really have been made and it should be changed back to what was there before, ie., just:req.write(result)
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As an an example of an Apache module that uses output filters to do stuff, there is mod_cache. Luckily in that case, a HEAD request is one of various cases where mod_cache decides it will not use the output. This does not mean though that some other output filter that someone is using might expect content to be there for HEAD.
I am not sure I agree with this explanation (while I do agree that the behaviour should be reverted, but for different reason, see below). The RFC is pretty clear on HEAD: "The HEAD method is identical to GET except that the server MUST NOT return a message-body in the response.", so for a filter (or anything) to expect the content with HEAD is wrong.
In summary, one could also say that if a user wants to not output anything for a HEAD request, that is there decision, but mod_python.publisher should not be making that decision for them.
May be not for the publisher, but given the "MUST NOT" it should be OK for either httpd or mod_python to do this. If httpd does not do it, then perhaps it should be made part of req.write()? It may be a good idea to check the httpd-dev archives to see if the issue of HEAD has been discussed in the past.
In any event, I think the behaviour should be reverted to ignore HEAD for now simply because it is a half-ass solution given that req.write() gets through, especially because PSP templates rely on req.write() primarily.
I think for 3.2 we can just leave it at that, but for 3.3 to seriously consider whether mod_python should chop output for HEAD requests.
Also, I think a link to this JIRA issue as a comment somewhere in the code would be great or someone down the road will repeat this whole HEAD thing again.
Grisha
