Store exceptions raised by `abort` in the WSGI environ.

This makes it easier to access the original exception later in the request cycle (e.g., other middleware or in custom error handlers).

docs/source/routing.rst

@@ -163,6 +163,13 @@ Pecan also comes with ``abort``, a utility function for raising HTTP errors:
             abort(404)
 
 
+Under the hood, ``abort`` raises an instance of
+``webob.exc.WSGIHTTPException`` which is used by pecan to render default
+response bodies for HTTP errors.  This exception is stored in the WSGI request
+environ at ``pecan.original_exception``, where it can be accessed later in the
+request cycle (by, for example, other middleware or :ref:`errors`).
+
+
 Routing to Subcontrollers with ``_lookup``
 ------------------------------------------
 

pecan/core.py

@@ -545,6 +545,7 @@ class Pecan(object):
             # if this is an HTTP Exception, set it as the response
             if isinstance(e, exc.HTTPException):
                 state.response = e
+                environ['pecan.original_exception'] = e
 
             # if this is not an internal redirect, run error hooks
             if not isinstance(e, ForwardRequestException):

pecan/tests/middleware/test_errordocument.py

@@ -1,5 +1,8 @@
+import json
+
 from webtest import TestApp
 
+import pecan
 from pecan.middleware.errordocument import ErrorDocumentMiddleware
 from pecan.middleware.recursive import RecursiveMiddleware
 from pecan.tests import PecanTestCase
@@ -52,3 +55,36 @@ class TestErrorDocumentMiddleware(PecanTestCase):
         assert r.status_int == 404
         assert r.body == ('Error: 404 Not Found.  '
                           '(Error page could not be fetched)')
+
+    def test_original_exception(self):
+
+        class RootController(object):
+
+            @pecan.expose()
+            def index(self):
+                if pecan.request.method != 'POST':
+                    pecan.abort(405, 'You have to POST, dummy!')
+                return 'Hello, World!'
+
+            @pecan.expose('json')
+            def error(self, status):
+                return dict(
+                    status=int(status),
+                    reason=pecan.request.environ[
+                        'pecan.original_exception'
+                    ].detail
+                )
+
+        app = pecan.Pecan(RootController())
+        app = RecursiveMiddleware(ErrorDocumentMiddleware(app, {
+            405: '/error/405'
+        }))
+        app = TestApp(app)
+
+        assert app.post('/').status_int == 200
+        r = app.get('/', expect_errors=405)
+        assert r.status_int == 405
+
+        resp = json.loads(r.body)
+        assert resp['status'] == 405
+        assert resp['reason'] == 'You have to POST, dummy!'