Added a new extension for oauth2 providers that integrates with flask.

Modified the existing scopes argument for django provider so that it now will
accept a function as well as a list object. This is done so that scopes can be dynamically
set.

AUTHORS

@@ -13,3 +13,4 @@ Silas Snider
 Tom Christie
 Chez
 Ondrej Slinták
+Mackenzie Thompson

oauthlib/oauth2/ext/flask.py

@@ -0,0 +1,116 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals, absolute_import
+from flask import abort, g, make_response, redirect, request, session
+import functools
+import logging
+from oauthlib.common import urlencode
+from oauthlib.oauth2.draft25 import errors
+
+log = logging.getLogger('oauthlib')
+
+
+class OAuth2ProviderDecorator(object):
+
+    def __init__(self, error_uri, server=None, authorization_endpoint=None,
+            token_endpoint=None, resource_endpoint=None):
+        self._authorization_endpoint = authorization_endpoint or server
+        self._token_endpoint = token_endpoint or server
+        self._resource_endpoint = resource_endpoint or server
+        self._error_uri = error_uri
+
+    def _extract_params(self):
+        log.debug('Extracting parameters from request.')
+        uri = request.url
+        http_method = request.method
+        headers = dict(request.headers)
+        if 'wsgi.input' in headers:
+            del headers['wsgi.input']
+        if 'wsgi.errors' in headers:
+            del headers['wsgi.errors']
+        if 'HTTP_AUTHORIZATION' in headers:
+            headers['Authorization'] = headers['HTTP_AUTHORIZATION']
+        body = urlencode(request.form.items())
+        return uri, http_method, body, headers
+
+    def pre_authorization_view(self, f):
+        @functools.wraps(f)
+        def wrapper(*args, **kwargs):
+            uri, http_method, body, headers = self._extract_params()
+            redirect_uri = request.args.get('redirect_uri', None)
+            log.debug('Found redirect uri %s.', redirect_uri)
+            try:
+                scopes, credentials = self._authorization_endpoint.validate_authorization_request(
+                        uri, http_method, body, headers)
+                log.debug('Saving credentials to session, %r.', credentials)
+                session['oauth2_credentials'] = credentials
+                kwargs['scopes'] = scopes
+                kwargs.update(credentials)
+                log.debug('Invoking view method, %r.', f)
+                return f(*args, **kwargs)
+
+            except errors.FatalClientError as e:
+                log.debug('Fatal client error, redirecting to error page.')
+                return redirect(e.in_uri(self._error_uri))
+        return wrapper
+
+    def post_authorization_view(self, f):
+        @functools.wraps(f)
+        def wrapper(*args, **kwargs):
+            uri, http_method, body, headers = self._extract_params()
+            scopes, credentials = f(*args, **kwargs)
+            log.debug('Fetched credentials view, %r.', credentials)
+            credentials.update(request.session.get('oauth2_credentials', {}))
+            log.debug('Fetched credentials from session, %r.', credentials)
+            redirect_uri = credentials.get('redirect_uri')
+            log.debug('Found redirect uri %s.', redirect_uri)
+            try:
+                url, headers, body, status = self._authorization_endpoint.create_authorization_response(
+                        uri, http_method, body, headers, scopes, credentials)
+                log.debug('Authorization successful, redirecting to client.')
+                return redirect(url)
+            except errors.FatalClientError as e:
+                log.debug('Fatal client error, redirecting to error page.')
+                return redirect(e.in_uri(self._error_uri))
+            except errors.OAuth2Error as e:
+                log.debug('Client error, redirecting back to client.')
+                return redirect(e.in_uri(redirect_uri))
+
+        return wrapper
+
+    def access_token_view(self, f):
+        @functools.wraps(f)
+        def wrapper(*args, **kwargs):
+            uri, http_method, body, headers = self._extract_params()
+            credentials = f(*args, **kwargs)
+            log.debug('Fetched credentials view, %r.', credentials)
+            url, headers, body, status = self._token_endpoint.create_token_response(
+                    uri, http_method, body, headers, credentials)
+            response = make_response(body, status)
+            for k, v in headers.items():
+                response.headers[k] = v
+            return response
+        return wrapper
+
+    def protected_resource_view(self, scopes=None, forbidden=None):
+        def decorator(f):
+            @functools.wraps(f)
+            def wrapper(*args, **kwargs):
+                try:
+                    scopes_list = scopes()
+                except TypeError:
+                    scopes_list = scopes
+                uri, http_method, body, headers = self._extract_params()
+                valid, r = self._resource_endpoint.verify_request(
+                        uri, http_method, body, headers, scopes_list)
+                g.client = r.client
+                g.user = r.user
+                g.scopes = r.scopes
+                g.token_scopes = r.token_scopes
+                if valid:
+                    return f(*args, **kwargs)
+                elif forbidden is not None:
+                    return forbidden()
+                else:
+                    abort(401)
+            return wrapper
+        return decorator