[Twisted-web] Re: [Web-SIG] WSGI - alternate ideas, part II

Peter Hunt floydophone at gmail.com
Thu Sep 16 06:02:38 MDT 2004

I think that the application should be passed a finish() method as a
parameter or start_response return value. If the WSGI application is
not a generator and returns wsgi.NOT_DONE_YET (similar to
Twisted.web's NOT_DONE_YET), it is required to call finish().
Otherwise, the gateway will call finish() after the generator is
finished or a string value is returned.

That way, one could do all of the deferred calls they want, and simply
return NOT_DONE_YET and call finish().

How does that sound?

On Wed, 15 Sep 2004 23:27:18 -0400, Phillip J. Eby
<pje at telecommunity.com> wrote:
> At 11:06 PM 9/15/04 -0400, Peter Hunt wrote:
> >Thus, here is my "WSGI-X" proposal. The application will call the
> >gateway, opposite of WSGI. For example, a CGI WSGI-X application may
> >begin with:
> >
> >#!/usr/bin/env python
> >if __name__ == "__main__":
> >       from wsgix import cgi
> >       req = cgi.get_request()
> That's pretty hard to implement correctly in any number of
> servers.  Really, pretty much every server wants to call the application,
> rather than the other way around, because servers want to use their own
> event loop.
> >stdout - the raw, unbuffered direct output stream to the client
> So, header parsing is required?  Or are only 'nph-' CGI scripts allowed?
> >Now we have a basic interface to interact with HTTP. If one wants to
> >write an extension to provide services like simplified cookie
> >handling, sessions, or buffered headers and content, they write an
> >extension function. A simple one for cookies would look like:
> >
> >def cookie_extension(req):
> >       if not hasattr(req, "cookie"):
> >             req.cookie =
> > Cookie.SimpleCookie(req.environ.get("HTTP_COOKIE",""))
> Note that this can easily be accomplished in WSGI, by changing
> 'hasattr(req,"cookie")' to '"my_extension.cookie" in environ' and
> 'req.cookie' to 'environ["my_extension.cookie"]'.
> >It modifies the request object if it hasn't already been modified.
> >This saves us a bit of overhead so we won't need to parse the cookie
> >again in case it is called twice (as it will if other extensions
> >depend on it).
> Also achievable within 'environ'.
> >Finish hooks have the same signature and execute when
> >the finish() method is called. For example, a buffering extension
> >would flush the buffer. Extensions can also add methods to the request
> >object, for items such as add_header().
> Under WSGI, such "finish" hooks can be rendered as a 'close()' method on an
> iterable by a piece of middleware.

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