Send 400 for BadDataError. (#202). r=rail

auslib/test/web/test_client.py

@@ -918,12 +918,11 @@ def testEmptySnippetOn500(self):
             self.assertEqual('I break!', str(exc.exception.message))
 
     def testSentryBadDataError(self):
-        with mock.patch("auslib.web.views.client.ClientRequestView.get") as m:
+        with mock.patch("auslib.web.views.client.ClientRequestView.get") as m, mock.patch("auslib.web.base.sentry") as sentry:
             m.side_effect = BadDataError("exterminate!")
-            with mock.patch("auslib.web.base.sentry") as sentry, self.assertRaises(Exception) as exc:
-                self.client.get("/update/4/b/1.0/1/p/l/a/a/a/a/1/update.xml")
+            ret = self.client.get("/update/4/b/1.0/1/p/l/a/a/a/a/1/update.xml")
             self.assertFalse(sentry.captureException.called)
-            self.assertEqual('exterminate!', str(exc.exception.message))
+            self.assertEqual(ret.status_code, 400, ret.data)
 
     def testSentryRealError(self):
         with mock.patch("auslib.web.views.client.ClientRequestView.get") as m:

auslib/web/base.py

@@ -1,7 +1,7 @@
 import logging
 log = logging.getLogger(__name__)
 
-from flask import Flask, make_response, send_from_directory, abort
+from flask import Flask, make_response, send_from_directory, abort, Response
 
 from raven.contrib.flask import Sentry
 
@@ -37,13 +37,15 @@ def fourohfour(error):
 @app.errorhandler(Exception)
 def generic(error):
     """Deals with any unhandled exceptions. If the exception is not a
-    BadDataError, it will be sent to Sentry. Regardless of the exception,
-    a 500 response is returned."""
+    BadDataError, it will be sent to Sentry, and a 400 will be returned,
+    because BadDataErrors are considered to be the client's fault.
+    Otherwise, the error is just re-raised (which causes a 500)."""
 
-    if not isinstance(error, BadDataError):
-        if sentry.client:
-            sentry.captureException()
+    if isinstance(error, BadDataError):
+        return Response(status=400, response=error.message)
 
+    if sentry.client:
+        sentry.captureException()
     raise error