WSGI question: reading headers before message body has been read

Graham Dumpleton Graham.Dumpleton at gmail.com
Sun Jan 18 22:25:38 CET 2009


On Jan 19, 6:43 am, Petite Abeille <petite.abei... at gmail.com> wrote:
> On Jan 18, 2009, at 8:01 PM, Ron Garret wrote:
>
> > def application(environ, start_response):
> >    status = "200 OK"
> >    headers = [('Content-Type', 'text/html'), ]
> >    start_response(status, headers)
> >    if int(environ['CONTENT_LENGTH'])>1000: return 'File too big'
>
> How would that work for chunked transfer-encoding?

Chunked transfer encoding on request content is not supported by WSGI
specification as WSGI requires CONTENT_LENGTH be set and disallows
reading more than defined content length, where CONTENT_LENGTH is
supposed to be taken as 0 if not provided.

If using Apache/mod_wsgi 3.0 (currently in development, so need to use
subversion copy), you can step outside what WSGI strictly allows and
still handle chunked transfer encoding on request content, but you
still don't have a CONTENT_LENGTH so as to check in advance if more
data than expected is going to be sent.

If wanting to know how to handle chunked transfer encoding in
mod_wsgi, better off asking on mod_wsgi list.

Graham



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