From 075b6b11c8b1690d946b8839e6dc4eb8a8cb7e3c Mon Sep 17 00:00:00 2001
From: James Saryerwinnie <jls.npi@gmail.com>
Date: Sun, 11 Mar 2012 20:45:58 -0700
Subject: [PATCH] Fix issue 140

This allows for a view function to return something like:

    jsonify(error="error msg"), 400
---
 CHANGES                  |  3 +++
 flask/app.py             | 16 +++++++++++++++-
 flask/testsuite/basic.py | 29 +++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/CHANGES b/CHANGES
index 8311e2e7..dbf447db 100644
--- a/CHANGES
+++ b/CHANGES
@@ -45,6 +45,9 @@ Relase date to be decided, codename to be chosen.
 - The :meth:`flask.render_template` method now accepts a either an iterable of
   template names or a single template name.  Previously, it only accepted a
   single template name.  On an iterable, the first template found is rendered.
+- View functions can now return a tuple with the first instance being an
+  instance of :class:`flask.Response`.  This allows for returning
+  ``jsonify(error="error msg"), 400`` from a view function.
 
 
 Version 0.8.1
diff --git a/flask/app.py b/flask/app.py
index 15e432de..f3d7efcb 100644
--- a/flask/app.py
+++ b/flask/app.py
@@ -1361,7 +1361,21 @@ class Flask(_PackageBoundObject):
         if isinstance(rv, basestring):
             return self.response_class(rv)
         if isinstance(rv, tuple):
-            return self.response_class(*rv)
+            if len(rv) > 0 and isinstance(rv[0], self.response_class):
+                original = rv[0]
+                new_response = self.response_class('', *rv[1:])
+                if len(rv) < 3:
+                    # The args for the response class are
+                    # response=None, status=None, headers=None,
+                    # mimetype=None, content_type=None, ...
+                    # so if there's at least 3 elements the rv
+                    # tuple contains header information so the
+                    # headers from rv[0] "win."
+                    new_response.headers = original.headers
+                new_response.response = original.response
+                return new_response
+            else:
+                return self.response_class(*rv)
         return self.response_class.force_type(rv, request.environ)
 
     def create_url_adapter(self, request):
diff --git a/flask/testsuite/basic.py b/flask/testsuite/basic.py
index e6a278e5..41efb196 100644
--- a/flask/testsuite/basic.py
+++ b/flask/testsuite/basic.py
@@ -659,6 +659,35 @@ class BasicFunctionalityTestCase(FlaskTestCase):
             self.assert_equal(rv.data, 'W00t')
             self.assert_equal(rv.mimetype, 'text/html')
 
+    def test_make_response_with_response_instance(self):
+        app = flask.Flask(__name__)
+        with app.test_request_context():
+            rv = flask.make_response(
+                flask.jsonify({'msg': 'W00t'}), 400)
+            self.assertEqual(rv.status_code, 400)
+            self.assertEqual(rv.data,
+                             '{\n  "msg": "W00t"\n}')
+            self.assertEqual(rv.mimetype, 'application/json')
+
+            rv = flask.make_response(
+                flask.Response(''), 400)
+            self.assertEqual(rv.status_code, 400)
+            self.assertEqual(rv.data, '')
+            self.assertEqual(rv.mimetype, 'text/html')
+
+            rv = flask.make_response(
+                flask.Response('', headers={'Content-Type': 'text/html'}),
+                400, None, 'application/json')
+            self.assertEqual(rv.status_code, 400)
+            self.assertEqual(rv.headers['Content-Type'], 'application/json')
+
+            rv = flask.make_response(
+                flask.Response('', mimetype='application/json'),
+                400, {'Content-Type': 'text/html'})
+            self.assertEqual(rv.status_code, 400)
+            self.assertEqual(rv.headers['Content-Type'], 'text/html')
+
+
     def test_url_generation(self):
         app = flask.Flask(__name__)
         @app.route('/hello/<name>', methods=['POST'])