Rename 'clean_headers' to 'header_control'.

This is part of adding the ability to forcefully set headers through the
middleware in addition to removing specific headers.

common/djangoapps/clean_headers/__init__.py

@@ -1,15 +0,0 @@
-"""
-This middleware is used for cleaning headers from a response before it is sent to the end user.
-
-Due to the nature of how middleware runs, a piece of middleware high in the chain cannot ensure
-that response headers won't be present on the final response body, as middleware further down
-the chain could be adding them.
-
-This middleware is intended to sit as close as possible to the top of the list, so that it has
-a chance on the reponse going out to strip the intended headers.
-"""
-
-
-def remove_headers_from_response(response, *headers):
-    """Removes the given headers from the response using the clean_headers middleware."""
-    response.clean_headers = headers

common/djangoapps/clean_headers/decorators.py

@@ -1,36 +0,0 @@
-"""
-Middleware decorator for removing headers.
-"""
-
-from functools import wraps
-
-
-def clean_headers(*headers):
-    """
-    Decorator that removes any headers specified from the response.
-    Usage:
-        @clean_headers("Vary")
-        def myview(request):
-            ...
-
-    The CleanHeadersMiddleware must be used and placed as closely as possible to the top
-    of the middleware chain, ideally after any caching middleware but before everything else.
-
-    This decorator is not safe for multiple uses: each call will overwrite any previously set values.
-    """
-    def _decorator(func):
-        """
-        Decorates the given function.
-        """
-        @wraps(func)
-        def _inner(*args, **kwargs):
-            """
-            Alters the response.
-            """
-            response = func(*args, **kwargs)
-            response.clean_headers = headers
-            return response
-
-        return _inner
-
-    return _decorator

common/djangoapps/clean_headers/middleware.py

@@ -1,25 +0,0 @@
-"""
-Middleware used for cleaning headers from a response before it is sent to the end user.
-"""
-
-
-class CleanHeadersMiddleware(object):
-    """
-    Middleware that can drop headers present in a response.
-
-    This can be used, for example, to remove headers i.e. drop any Vary headers to improve cache performance.
-    """
-
-    def process_response(self, _request, response):
-        """
-        Processes the given response, potentially stripping out any unwanted headers.
-        """
-
-        if len(getattr(response, 'clean_headers', [])) > 0:
-            for header in response.clean_headers:
-                try:
-                    del response[header]
-                except KeyError:
-                    pass
-
-        return response

common/djangoapps/clean_headers/tests/test_decorators.py

@@ -1,20 +0,0 @@
-"""Tests for clean_headers decorator. """
-from django.http import HttpResponse, HttpRequest
-from django.test import TestCase
-from clean_headers.decorators import clean_headers
-
-
-def fake_view(_request):
-    """Fake view that returns an empty response."""
-    return HttpResponse()
-
-
-class TestCleanHeaders(TestCase):
-    """Test the `clean_headers` decorator."""
-
-    def test_clean_headers(self):
-        request = HttpRequest()
-        wrapper = clean_headers('Vary', 'Accept-Encoding')
-        wrapped_view = wrapper(fake_view)
-        response = wrapped_view(request)
-        self.assertEqual(len(response.clean_headers), 2)

common/djangoapps/clean_headers/tests/test_middleware.py

@@ -1,34 +0,0 @@
-"""Tests for clean_headers middleware."""
-from django.http import HttpResponse, HttpRequest
-from django.test import TestCase
-from clean_headers.middleware import CleanHeadersMiddleware
-
-
-class TestCleanHeadersMiddlewareProcessResponse(TestCase):
-    """Test the `clean_headers` middleware. """
-    def setUp(self):
-        super(TestCleanHeadersMiddlewareProcessResponse, self).setUp()
-        self.middleware = CleanHeadersMiddleware()
-
-    def test_cleans_intended_headers(self):
-        fake_request = HttpRequest()
-
-        fake_response = HttpResponse()
-        fake_response['Vary'] = 'Cookie'
-        fake_response['Accept-Encoding'] = 'gzip'
-        fake_response.clean_headers = ['Vary']
-
-        result = self.middleware.process_response(fake_request, fake_response)
-        self.assertNotIn('Vary', result)
-        self.assertEquals('gzip', result['Accept-Encoding'])
-
-    def test_does_not_mangle_undecorated_response(self):
-        fake_request = HttpRequest()
-
-        fake_response = HttpResponse()
-        fake_response['Vary'] = 'Cookie'
-        fake_response['Accept-Encoding'] = 'gzip'
-
-        result = self.middleware.process_response(fake_request, fake_response)
-        self.assertEquals('Cookie', result['Vary'])
-        self.assertEquals('gzip', result['Accept-Encoding'])

common/djangoapps/header_control/__init__.py

@@ -0,0 +1,21 @@
+"""
+This middleware is used for adjusting the headers in a response before it is sent to the end user.
+
+This middleware is intended to sit as close as possible to the top of the middleare list as possible,
+so that it is one of the last pieces of middleware to touch the response, and thus can most accurately
+adjust/control the headers of the response.
+"""
+
+
+def remove_headers_from_response(response, *headers):
+    """Removes the given headers from the response using the header_control middleware."""
+    response.remove_headers = headers
+
+def force_header_for_response(response, header, value):
+    """Forces the given header for the given response using the header_control middleware."""
+    force_headers = {}
+    if hasattr(response, 'force_headers'):
+        force_headers = response.force_headers
+    force_headers[header] = value
+
+    response.force_headers = force_headers

common/djangoapps/header_control/decorators.py

@@ -0,0 +1,67 @@
+"""
+Middleware decorator for removing headers.
+"""
+
+from functools import wraps
+from header_control import remove_headers_from_response, force_header_for_response
+
+def remove_headers(*headers):
+    """
+    Decorator that removes specific headers from the response.
+    Usage:
+        @remove_headers("Vary")
+        def myview(request):
+            ...
+
+    The HeaderControlMiddleware must be used and placed as closely as possible to the top
+    of the middleware chain, ideally after any caching middleware but before everything else.
+
+    This decorator is not safe for multiple uses: each call will overwrite any previously set values.
+    """
+    def _decorator(func):
+        """
+        Decorates the given function.
+        """
+        @wraps(func)
+        def _inner(*args, **kwargs):
+            """
+            Alters the response.
+            """
+            response = func(*args, **kwargs)
+            remove_headers_from_response(response, *headers)
+            return response
+
+        return _inner
+
+    return _decorator
+
+
+def force_header(header, value):
+    """
+    Decorator that forces a header in the response to have a specific value.
+    Usage:
+        @force_header("Vary", "Origin")
+        def myview(request):
+            ...
+
+    The HeaderControlMiddleware must be used and placed as closely as possible to the top
+    of the middleware chain, ideally after any caching middleware but before everything else.
+
+    This decorator is not safe for multiple uses: each call will overwrite any previously set values.
+    """
+    def _decorator(func):
+        """
+        Decorates the given function.
+        """
+        @wraps(func)
+        def _inner(*args, **kwargs):
+            """
+            Alters the response.
+            """
+            response = func(*args, **kwargs)
+            force_header_for_response(response, header, value)
+            return response
+
+        return _inner
+
+    return _decorator

common/djangoapps/header_control/middleware.py

@@ -0,0 +1,34 @@
+"""
+Middleware used for adjusting headers in a response before it is sent to the end user.
+"""
+
+
+class HeaderControlMiddleware(object):
+    """
+    Middleware that can modify/remove headers in a response.
+
+    This can be used, for example, to remove headers i.e. drop any Vary headers to improve cache performance.
+    """
+
+    def process_response(self, _request, response):
+        """
+        Processes the given response, potentially remove or modifying headers.
+        """
+
+        if len(getattr(response, 'remove_headers', [])) > 0:
+            for header in response.remove_headers:
+                try:
+                    del response[header]
+                except KeyError:
+                    pass
+
+        if len(getattr(response, 'force_headers', {})) > 0:
+            for header, value in response.force_headers.iteritems():
+                try:
+                    del response[header]
+                except KeyError:
+                    pass
+
+                response[header] = value
+
+        return response

common/djangoapps/header_control/tests/test_decorators.py

@@ -0,0 +1,32 @@
+"""Tests for remove_headers and force_header decorator. """
+from django.http import HttpResponse, HttpRequest
+from django.test import TestCase
+from header_control.decorators import remove_headers, force_header
+
+
+def fake_view(_request):
+    """Fake view that returns an empty response."""
+    return HttpResponse()
+
+
+class TestRemoveHeaders(TestCase):
+    """Test the `remove_headers` decorator."""
+
+    def test_remove_headers(self):
+        request = HttpRequest()
+        wrapper = remove_headers('Vary', 'Accept-Encoding')
+        wrapped_view = wrapper(fake_view)
+        response = wrapped_view(request)
+        self.assertEqual(len(response.remove_headers), 2)
+
+
+class TestForceHeader(TestCase):
+    """Test the `force_header` decorator."""
+
+    def test_force_header(self):
+        request = HttpRequest()
+        wrapper = force_header('Vary', 'Origin')
+        wrapped_view = wrapper(fake_view)
+        response = wrapped_view(request)
+        self.assertEqual(len(response.force_headers), 1)
+        self.assertEqual(response.force_headers['Vary'], 'Origin')

common/djangoapps/header_control/tests/test_middleware.py

@@ -0,0 +1,47 @@
+"""Tests for header_control middleware."""
+from django.http import HttpResponse, HttpRequest
+from django.test import TestCase
+from header_control import remove_headers_from_response, force_header_for_response
+from header_control.middleware import HeaderControlMiddleware
+
+
+class TestHeaderControlMiddlewareProcessResponse(TestCase):
+    """Test the `header_control` middleware. """
+    def setUp(self):
+        super(TestHeaderControlMiddlewareProcessResponse, self).setUp()
+        self.middleware = HeaderControlMiddleware()
+
+    def test_removes_intended_headers(self):
+        fake_request = HttpRequest()
+
+        fake_response = HttpResponse()
+        fake_response['Vary'] = 'Cookie'
+        fake_response['Accept-Encoding'] = 'gzip'
+        remove_headers_from_response(fake_response, 'Vary')
+
+        result = self.middleware.process_response(fake_request, fake_response)
+        self.assertNotIn('Vary', result)
+        self.assertEquals('gzip', result['Accept-Encoding'])
+
+    def test_forces_intended_header(self):
+        fake_request = HttpRequest()
+
+        fake_response = HttpResponse()
+        fake_response['Vary'] = 'Cookie'
+        fake_response['Accept-Encoding'] = 'gzip'
+        force_header_for_response(fake_response, 'Vary', 'Origin')
+
+        result = self.middleware.process_response(fake_request, fake_response)
+        self.assertEquals('Origin', result['Vary'])
+        self.assertEquals('gzip', result['Accept-Encoding'])
+
+    def test_does_not_mangle_undecorated_response(self):
+        fake_request = HttpRequest()
+
+        fake_response = HttpResponse()
+        fake_response['Vary'] = 'Cookie'
+        fake_response['Accept-Encoding'] = 'gzip'
+
+        result = self.middleware.process_response(fake_request, fake_response)
+        self.assertEquals('Cookie', result['Vary'])
+        self.assertEquals('gzip', result['Accept-Encoding'])

lms/envs/common.py

@@ -1087,7 +1087,7 @@ simplefilter('ignore')
 
 MIDDLEWARE_CLASSES = (
     'request_cache.middleware.RequestCache',
-    'clean_headers.middleware.CleanHeadersMiddleware',
+    'header_control.middleware.HeaderControlMiddleware',
     'microsite_configuration.middleware.MicrositeMiddleware',
     'django_comment_client.middleware.AjaxExceptionMiddleware',
     'django.middleware.common.CommonMiddleware',