I know other people weren't psyched about this one, but it's *so easy* to define. As evidence of its applicability to more than just Paste, I just checked the Zope 3 source, and it uses environ['wsgi.handleErrors'] for this same purpose. Also there are multiple WSGI testing frameworks that could use this key in their environments.
The spec is at: http://wsgi.org/wsgi/Specifications/throw_errors Copied: :Title: x-wsgiorg.throw_errors :Author: Ian Bicking <[EMAIL PROTECTED]> :Discussions-To: Python Web-SIG <[email protected]> :Status: Proposed :Created: 13 Nov 2006 .. contents:: Abstract -------- WSGI applications are generally not supposed to raise exceptions, instead handling their own errors (possibly returning a ``500 Server Error`` response). But in some context it is *desired* that unexpected exceptions be allowed to bubble up. This specification defines a key to set in this circumstance. Rationale --------- When in a testing context it is undesirable for an application to handle its own errors. Typically the test framework is better at handling the errors, either through error formatting or by dropping into a debugger like `pdb <http://python.org/doc/current/lib/module-pdb.html>`_. Additionally when an exception catcher is installed in a stack, ideally it will be used for all exceptions. This allows for centralized configuration (for example, when emails are sent when errors occur). Dynamically disabling any other exception catchers is often ideal in this situation. Specification ------------- An exception catcher should check for ``environ.get('x-wsgiorg.throw_errors')`` in the environment. If it is true, it should not try to catch exceptions. This need only be checked as the application is being entered, it should not be checked later. Applications should not try to set this to effect middleware that *wraps* them, only to effect applications they may call. Example -------- A simple exception catcher:: class ExceptionCatch(object): def __init__(self, app): self.app = app def __call__(self, environ, start_response): if environ.get('x-wsgiorg.throw_errors'): return self.app(environ, start_response) try: return self.app(environ, start_response) except: import sys, traceback, StringIO exc_info = sys.exc_info() start_response('500 Server Error', [('content-type', 'text/plain')], exc_info=exc_info) out = StringIO.StringIO() traceback.print_exc(file=out) return [out.getvalue()] Problems -------- * In theory an application may know better how to format an error response than the middleware exception catcher. Of course, an application can ignore ``x-wsgiorg.throw_errors`` if it thinks it is best (or if it has been explicitly configured to do so). Other Possibilities ------------------- * You can just get the unwrapped application object and test it. Open Issues ----------- * None I know of _______________________________________________ Web-SIG mailing list [email protected] Web SIG: http://www.python.org/sigs/web-sig Unsubscribe: http://mail.python.org/mailman/options/web-sig/archive%40mail-archive.com
