werkzeug.ClosingIterator¶

class werkzeug.ClosingIterator(iterable, callbacks=None)[source]¶

The WSGI specification requires that all middlewares and gateways respect the close callback of an iterator. Because it is useful to add another close action to a returned iterator and adding a custom iterator is a boring task this class can be used for that:

return ClosingIterator(app(environ, start_response), [cleanup_session,
                                                      cleanup_locals])

If there is just one close function it can be passed instead of the list.

A closing iterator is not needed if the application uses response objects and finishes the processing if the response is started:

try:
    return response(environ, start_response)
finally:
    cleanup_session()
    cleanup_locals()