1 files changed, 61 insertions, 0 deletions
diff --git a/webapp/django/utils/decorators.py b/webapp/django/utils/decorators.py
new file mode 100644
index 0000000000..8fc4c1d96a
--- /dev/null
+++ b/webapp/django/utils/decorators.py
@@ -0,0 +1,61 @@
+"Functions that help with dynamically creating decorators for views."
+
+import types
+try:
+    from functools import wraps
+except ImportError:
+    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.
+
+def decorator_from_middleware(middleware_class):
+    """
+    Given a middleware class (not an instance), returns a view decorator. This
+    lets you use middleware functionality on a per-view basis.
+    """
+    def _decorator_from_middleware(*args, **kwargs):
+        # For historical reasons, these "decorators" are also called as
+        # dec(func, *args) instead of dec(*args)(func). We handle both forms
+        # for backwards compatibility.
+        has_func = True
+        try:
+            view_func = kwargs.pop('view_func')
+        except KeyError:
+            if len(args):
+                view_func, args = args[0], args[1:]
+            else:
+                has_func = False
+        if not (has_func and isinstance(view_func, types.FunctionType)):
+            # We are being called as a decorator.
+            if has_func:
+                args = (view_func,) + args
+            middleware = middleware_class(*args, **kwargs)
+
+            def decorator_func(fn):
+                return _decorator_from_middleware(fn, *args, **kwargs)
+            return decorator_func
+
+        middleware = middleware_class(*args, **kwargs)
+
+        def _wrapped_view(request, *args, **kwargs):
+            if hasattr(middleware, 'process_request'):
+                result = middleware.process_request(request)
+                if result is not None:
+                    return result
+            if hasattr(middleware, 'process_view'):
+                result = middleware.process_view(request, view_func, args, kwargs)
+                if result is not None:
+                    return result
+            try:
+                response = view_func(request, *args, **kwargs)
+            except Exception, e:
+                if hasattr(middleware, 'process_exception'):
+                    result = middleware.process_exception(request, e)
+                    if result is not None:
+                        return result
+                raise
+            if hasattr(middleware, 'process_response'):
+                result = middleware.process_response(request, response)
+                if result is not None:
+                    return result
+            return response
+        return wraps(view_func)(_wrapped_view)
+    return _decorator_from_middleware