Added support for automagic OPTIONS

CHANGES

@@ -10,6 +10,9 @@ Release date to be announced, codename to be decided.
 
 - after request functions are now called in reverse order of
   registration.
+- OPTIONS is now automatically implemented by Flask unless the
+  application explictly adds 'OPTIONS' as method to the URL rule.
+  In this case no automatic OPTIONS handling kicks in.
 
 Version 0.5.1
 -------------

docs/quickstart.rst

@@ -269,7 +269,8 @@ If `GET` is present, `HEAD` will be added automatically for you.  You
 don't have to deal with that.  It will also make sure that `HEAD` requests
 are handled like the `HTTP RFC`_ (the document describing the HTTP
 protocol) demands, so you can completely ignore that part of the HTTP
-specification.
+specification.  Likewise as of Flask 0.6, `OPTIONS` is implemented for you
+as well automatically.
 
 You have no idea what an HTTP method is?  Worry not, here quick
 introduction in HTTP methods and why they matter:
@@ -310,6 +311,11 @@ very common:
 `DELETE`
     Remove the information that the given location.
 
+`OPTIONS`
+    Provides a quick way for a requesting client to figure out which
+    methods are supported by this URL.  Starting with Flask 0.6, this
+    is implemented for you automatically.
+
 Now the interesting part is that in HTML4 and XHTML1, the only methods a
 form might submit to the server are `GET` and `POST`.  But with JavaScript
 and future HTML standards you can use other methods as well.  Furthermore

flask/app.py

@@ -464,6 +464,9 @@ class Flask(_PackageBoundObject):
         .. versionchanged:: 0.2
            `view_func` parameter added.
 
+        .. versionchanged:: 0.6
+           `OPTIONS` is added automatically as method.
+
         :param rule: the URL rule as string
         :param endpoint: the endpoint for the registered URL rule.  Flask
                          itself assumes the name of the view function as
@@ -471,15 +474,27 @@ class Flask(_PackageBoundObject):
         :param view_func: the function to call when serving a request to the
                           provided endpoint
         :param options: the options to be forwarded to the underlying
-                        :class:`~werkzeug.routing.Rule` object
+                        :class:`~werkzeug.routing.Rule` object.  A change
+                        to Werkzeug is handling of method options.  methods
+                        is a list of methods this rule should be limited
+                        to (`GET`, `POST` etc.).  By default a rule
+                        just listens for `GET` (and implicitly `HEAD`).
+                        Starting with Flask 0.6, `OPTIONS` is implicitly
+                        added and handled by the standard request handling.
         """
         if endpoint is None:
             assert view_func is not None, 'expected view func if endpoint ' \
                                           'is not provided.'
             endpoint = view_func.__name__
         options['endpoint'] = endpoint
-        options.setdefault('methods', ('GET',))
-        self.url_map.add(Rule(rule, **options))
+        methods = options.pop('methods', ('GET',))
+        provide_automatic_options = False
+        if 'OPTIONS' not in methods:
+            methods = tuple(methods) + ('OPTIONS',)
+            provide_automatic_options = True
+        rule = Rule(rule, methods=methods, **options)
+        rule.provide_automatic_options = provide_automatic_options
+        self.url_map.add(rule)
         if view_func is not None:
             self.view_functions[endpoint] = view_func
 
@@ -539,8 +554,10 @@ class Flask(_PackageBoundObject):
 
         :param rule: the URL rule as string
         :param methods: a list of methods this rule should be limited
-                        to (``GET``, ``POST`` etc.).  By default a rule
-                        just listens for ``GET`` (and implicitly ``HEAD``).
+                        to (`GET`, `POST` etc.).  By default a rule
+                        just listens for `GET` (and implicitly `HEAD`).
+                        Starting with Flask 0.6, `OPTIONS` is implicitly
+                        added and handled by the standard request handling.
         :param subdomain: specifies the rule for the subdomain in case
                           subdomain matching is in use.
         :param strict_slashes: can be used to disable the strict slashes
@@ -650,7 +667,15 @@ class Flask(_PackageBoundObject):
         try:
             if req.routing_exception is not None:
                 raise req.routing_exception
-            return self.view_functions[req.endpoint](**req.view_args)
+            rule = req.url_rule
+            # if we provide automatic options for this URL and the
+            # request came with the OPTIONS method, reply automatically 
+            if rule.provide_automatic_options and req.method == 'OPTIONS':
+                rv = self.response_class()
+                rv.allow.update(rule.methods)
+                return rv
+            # otherwise dispatch to the handler for that endpoint
+            return self.view_functions[rule.endpoint](**req.view_args)
         except HTTPException, e:
             return self.handle_http_exception(e)
 

flask/ctx.py

@@ -38,8 +38,9 @@ class _RequestContext(object):
         self.flashes = None
 
         try:
-            self.request.endpoint, self.request.view_args = \
-                self.url_adapter.match()
+            url_rule, self.request.view_args = \
+                self.url_adapter.match(return_rule=True)
+            self.request.url_rule = url_rule
         except HTTPException, e:
             self.request.routing_exception = e
 

flask/helpers.py

@@ -15,6 +15,7 @@ import posixpath
 import mimetypes
 from time import time
 from zlib import adler32
+from functools import wraps
 
 # try to load the best simplejson implementation available.  If JSON
 # is not installed, we add a failing class.

flask/wrappers.py

@@ -24,11 +24,12 @@ class Request(RequestBase):
     :attr:`~flask.Flask.request_class` to your subclass.
     """
 
-    #: the endpoint that matched the request.  This in combination with
-    #: :attr:`view_args` can be used to reconstruct the same or a
-    #: modified URL.  If an exception happened when matching, this will
-    #: be `None`.
-    endpoint = None
+    #: the internal URL rule that matched the request.  This can be
+    #: useful to inspect which methods are allowed for the URL from
+    #: a before/after handler (``request.url_rule.methods``) etc.
+    #:
+    #: .. versionadded:: 0.6
+    url_rule = None
 
     #: a dict of view arguments that matched the request.  If an exception
     #: happened when matching, this will be `None`.
@@ -40,6 +41,16 @@ class Request(RequestBase):
     #: something similar.
     routing_exception = None
 
+    @property
+    def endpoint(self):
+        """The endpoint that matched the request.  This in combination with
+        :attr:`view_args` can be used to reconstruct the same or a
+        modified URL.  If an exception happened when matching, this will
+        be `None`.
+        """
+        if self.url_rule is not None:
+            return self.url_rule.endpoint
+
     @property
     def module(self):
         """The name of the current module"""

tests/flask_tests.py

@@ -111,6 +111,15 @@ class ContextTestCase(unittest.TestCase):
 
 class BasicFunctionalityTestCase(unittest.TestCase):
 
+    def test_options_work(self):
+        app = flask.Flask(__name__)
+        @app.route('/', methods=['GET', 'POST'])
+        def index():
+            return 'Hello World'
+        rv = app.test_client().open('/', method='OPTIONS')
+        assert sorted(rv.allow) == ['GET', 'HEAD', 'OPTIONS', 'POST']
+        assert rv.data == ''
+
     def test_request_dispatching(self):
         app = flask.Flask(__name__)
         @app.route('/')
@@ -124,7 +133,7 @@ class BasicFunctionalityTestCase(unittest.TestCase):
         assert c.get('/').data == 'GET'
         rv = c.post('/')
         assert rv.status_code == 405
-        assert sorted(rv.allow) == ['GET', 'HEAD']
+        assert sorted(rv.allow) == ['GET', 'HEAD', 'OPTIONS']
         rv = c.head('/')
         assert rv.status_code == 200
         assert not rv.data  # head truncates
@@ -132,7 +141,7 @@ class BasicFunctionalityTestCase(unittest.TestCase):
         assert c.get('/more').data == 'GET'
         rv = c.delete('/more')
         assert rv.status_code == 405
-        assert sorted(rv.allow) == ['GET', 'HEAD', 'POST']
+        assert sorted(rv.allow) == ['GET', 'HEAD', 'OPTIONS', 'POST']
 
     def test_url_mapping(self):
         app = flask.Flask(__name__)
@@ -148,7 +157,7 @@ class BasicFunctionalityTestCase(unittest.TestCase):
         assert c.get('/').data == 'GET'
         rv = c.post('/')
         assert rv.status_code == 405
-        assert sorted(rv.allow) == ['GET', 'HEAD']
+        assert sorted(rv.allow) == ['GET', 'HEAD', 'OPTIONS']
         rv = c.head('/')
         assert rv.status_code == 200
         assert not rv.data  # head truncates
@@ -156,7 +165,7 @@ class BasicFunctionalityTestCase(unittest.TestCase):
         assert c.get('/more').data == 'GET'
         rv = c.delete('/more')
         assert rv.status_code == 405
-        assert sorted(rv.allow) == ['GET', 'HEAD', 'POST']
+        assert sorted(rv.allow) == ['GET', 'HEAD', 'OPTIONS', 'POST']
 
     def test_session(self):
         app = flask.Flask(__name__)