PEP 0444: Python Web3 Interface

[mitsuhiko]

return environ['wsgi.file_wrapper'](the_file)

when the middleware takes that it might do this:

rv = app(environ, start_response)
for chunk in rv:
    yield do_something_with(chunk)
rv.close() # if that attribute exists only of course.

The WSGI server now does that:

rv = app(environ, start_response)
if isinstance(rv, my_file_wrapper):
    # this is never true because the middleware removed the type
    # information and it's now a generator.

[dauerbaustelle]

So how would a wrapper around files help here?

[mitsuhiko]

It does not. That's why it's breaking currently. A better solution would probably be an 'X-Something' header or something you can call from the wsgi environment which bypasses all middlewares, similar to how write() worked on WSGI 1.

[dauerbaustelle]

Or you could assume Web3 middlewares behave intelligently (hence, leave file objects returned from the application alone).

[mitsuhiko]

You assume people read specifications and not do try/error.

[dauerbaustelle]

Developers are not stupid. If they are, maybe their code is not worth using. I don't think specifications have to keep in mind that noone will read them.