Add test for default Expect handler

aiohttp/web.py

@@ -76,7 +76,7 @@ def handle_request(self, message, payload):
             resp = None
             request._match_info = match_info
             expect = request.headers.get(hdrs.EXPECT)
-            if expect and expect.lower() == "100-continue":
+            if expect:
                 resp = (
                     yield from match_info.route.handle_expect_header(request))
 

aiohttp/web_urldispatcher.py

@@ -14,7 +14,8 @@
 from . import hdrs
 from .abc import AbstractRouter, AbstractMatchInfo
 from .protocol import HttpVersion11
-from .web_exceptions import HTTPMethodNotAllowed, HTTPNotFound, HTTPNotModified
+from .web_exceptions import (HTTPMethodNotAllowed, HTTPNotFound,
+                             HTTPNotModified, HTTPExpectationFailed)
 from .web_reqrep import StreamResponse
 from .multidict import upstr
 
@@ -43,9 +44,17 @@ def __repr__(self):
 
 @asyncio.coroutine
 def _defaultExpectHandler(request):
-    """Default handler for Except: 100-continue"""
+    """Default handler for Except header.
+
+    Just send "100 Continue" to client.
+    raise HTTPExpectationFailed if value of header is not "100-continue"
+    """
+    expect = request.headers.get(hdrs.EXPECT)
     if request.version == HttpVersion11:
-        request.transport.write(b"HTTP/1.1 100 Continue\r\n\r\n")
+        if expect.lower() == "100-continue":
+            request.transport.write(b"HTTP/1.1 100 Continue\r\n\r\n")
+        else:
+            raise HTTPExpectationFailed(text="Unknown Expect: %s" % expect)
 
 
 class Route(metaclass=abc.ABCMeta):

docs/web.rst

@@ -312,15 +312,26 @@ usually called *session*.
 
 .. versionadded:: 0.15
 
-:mod:`aiohttp.web` supports *Expect* header. By default
-it responds with an *HTTP/1.1 100 Continue* status code.
-It is possible to specify custom *Expect* header handler on per route basis.
-This handler gets called after receiving all headers and before
+:mod:`aiohttp.web` supports *Expect* header. By default it sends
+*HTTP/1.1 100 Continue* line to client, or raises HTTPExpectationFailed if
+header value is not equal to "100-continue". It is possible to specify
+custom *Expect* header handler on per route basis. This handler gets called
+if *Expect* header exist in request after receiving all headers and before
 processing application middlewares :ref:`aiohttp-web-middlewares` and route
 handler. Handler can return *None*, in that case the request processing
 continues as usual. If handler returns an instance of
-class :class:`StreamResponse`, *request handler* uses it as response.
-Custom handler *must* write *HTTP/1.1 100 Continue* status if all checks pass.
+class :class:`StreamResponse`, *request handler* uses it as response. Also
+handler can raise a subclass of HTTPException. In this case all further
+processing will not happen and client will receive appropriate http response.
+
+.. note::
+    A server that does not understand or is unable to comply with any of the
+    expectation values in the Expect field of a request MUST respond with
+    appropriate error status. The server MUST respond with a 417
+    (Expectation Failed) status if any of the expectations cannot be met or,
+    if there are other problems with the request, some other 4xx status.
+
+    http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.20
 
 This example shows custom handler for *Except* header:
 
@@ -330,8 +341,11 @@ This example shows custom handler for *Except* header:
        if request.version != aiohttp.HttpVersion11:
            return
 
+       if request.headers.get('EXPECT') != '100-continue':
+           raise HTTPExpectationFailed(text="Unknown Expect: %s" % expect)
+
        if request.headers.get('AUTHORIZATION') is None:
-           return web.HTTPForbidden()
+           raise HTTPForbidden()
 
        request.transport.write(b"HTTP/1.1 100 Continue\r\n\r\n")
 

tests/test_web_functional.py

@@ -357,6 +357,32 @@ def go():
 
         self.loop.run_until_complete(go())
 
+    def test_expect_default_handler_unknown(self):
+        """Test default Expect handler for unknown Expect value.
+
+        A server that does not understand or is unable to comply with any of
+        the expectation values in the Expect field of a request MUST respond
+        with appropriate error status. The server MUST respond with a 417
+        (Expectation Failed) status if any of the expectations cannot be met
+        or, if there are other problems with the request, some other 4xx
+        status.
+
+        http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.20
+        """
+        @asyncio.coroutine
+        def handler(request):
+            yield from request.post()
+            self.fail('Handler should not proceed to this point in case of '
+                      'unknown Expect header')
+
+        @asyncio.coroutine
+        def go():
+            _, _, url = yield from self.create_server('POST', '/', handler)
+            resp = yield from request('POST', url, headers={'Expect': 'SPAM'},
+                                      loop=self.loop)
+            self.assertEqual(417, resp.status)
+        self.loop.run_until_complete(go())
+
     def test_100_continue(self):
         @asyncio.coroutine
         def handler(request):