[mod_python] util.FieldStorage wrong about method restrictions

Mike Looijmans nlv11281 at natlab.research.philips.com
Mon Aug 14 07:03:34 EDT 2006

>>         if req.method == "POST" or req.method == "PUT":
>> The current version says something similar.
>> This is wrong. Or at least restictive.
> It may be restrictive but the cgi.FieldStorage class in the main Python
> distribution also only supports POST. Unless you can show some sort
> of precedent in the way of some other equivalent forms processing  library
> that supports PUT, I can't see any convincing reason to change it. Some
> sort of documentation as to what can be provided in a PUT request as
> content would also help.

The HTTP RFC 2068 (there's a later version too), as far as I can recall it, explains that only POST 
requests can be expected to have a body that contains FORM data. All other requests, like GET, PUT, 
OPTION and so on have entity bodies with different meaning.

For a PUT request, the standard expects the body to contain full (or partial since HTTP/1.1) 
contents of the entity refered to in the URL. A subsequent GET request for the same URL is expected 
to retrieve the contents as sent by the last PUT request.

For that reason, I would strongly object to implementing this patch in the FieldStorage class. It 
goes against the standards, and because of that, you're on your own here.

>> I noticed this because I am PUTting the representation of a resource
>> as application/x-www-form-urlencoded and I wasn't allowed to do that
>> using FieldStorage.

As explained, FieldStorage is correct in not allowing that. Either modify your application to adhere 
to the standard and use a POST request, or implement your own workaround that will make it work in 
your specific environment, for example using Graham's solution.


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