Added a post-mortem pdb middleware. Works like the PostmortemDebuggin…

…gHTTP server,

except that this does the debugging where it belongs, in a middleware, not in the
app and not in the server (yikes!).

z3c/evalexception.py

@@ -1,10 +1,47 @@
+import zope.security.management
 from paste.evalexception.middleware import EvalException
 
 class ZopeEvalException(EvalException):
+    """Wrapper around Paste's EvalException middleware that simply
+    tells zope.publisher to let exceptions propagate to the middleware."""
 
     def __call__(self, environ, start_response):
         environ['wsgi.handleErrors'] = False
         return super(ZopeEvalException, self).__call__(environ, start_response)
 
 def zope_eval_exception(app, global_conf):
     return ZopeEvalException(app)
+
+def PostMortemDebug(application):
+    """Middleware that catches exceptions coming from a
+    zope.publisher-based application and invokes pdb's post-mortem
+    debugging facility."""
+    def middleware(environ, start_response):
+        environ['wsgi.handleErrors'] = False
+        try:
+            for chunk in application(environ, start_response):
+                yield chunk
+        except:
+            import sys, pdb
+            print "%s:" % sys.exc_info()[0]
+            print sys.exc_info()[1]
+            zope.security.management.restoreInteraction()
+            try:
+                pdb.post_mortem(sys.exc_info()[2])
+                raise
+            finally:
+                zope.security.management.endInteraction()
+    return middleware
+
+def post_mortem_debug(app, global_conf):
+    return PostMortemDebug(app)
+
+def TestApplication(environ, start_response):
+    """A simple WSGI app that raises an exception for testing
+    purposes.  Nothing to see here."""
+    raise RuntimeError('The test application is raising this.')
+    start_response('200 OK', [('Content-type', 'text/plain')])
+    yield "Test Application"
+
+def test_application_factory(global_config):
+    return TestApplication