r46999 - Merge httpchannel-proxy-8193-3: Add proxy HTTPChannel object to allow swapping of channel after connection establishment

Author: hawkowl
Date: Tue Mar 15 09:18:31 2016
New Revision: 46999

Added:
   trunk/twisted/topfiles/8193.misc
Modified:
   trunk/twisted/web/http.py
   trunk/twisted/web/test/test_http.py
   trunk/twisted/web/test/test_web.py

Log:
Merge httpchannel-proxy-8193-3: Add proxy HTTPChannel object to allow swapping of channel after connection establishment

Author: lukasa
Reviewers: glyph, adiroiban, hawkowl
Fixes: #8193

Modified: trunk/twisted/web/http.py
==============================================================================
--- trunk/twisted/web/http.py	(original)
+++ trunk/twisted/web/http.py	Tue Mar 15 09:18:31 2016
@@ -97,11 +97,14 @@
 from twisted.python.components import proxyForInterface
 from twisted.internet import interfaces, reactor, protocol, address
 from twisted.internet.defer import Deferred
+from twisted.internet.interfaces import IProtocol
 from twisted.protocols import policies, basic
 
 from twisted.web.iweb import IRequest, IAccessLogFormatter
 from twisted.web.http_headers import Headers
 
+H2_ENABLED = False
+
 from twisted.web._responses import (
     SWITCHING,
 
@@ -1978,6 +1981,92 @@
 
 
 
+class _GenericHTTPChannelProtocol(proxyForInterface(IProtocol, "_channel")):
+    """
+    A proxy object that wraps one of the HTTP protocol objects, and switches
+    between them depending on TLS negotiated protocol.
+
+    @ivar _negotiatedProtocol: The protocol negotiated with ALPN or NPN, if
+        any.
+    @type _negotiatedProtocol: Either a bytestring containing the ALPN token
+        for the negotiated protocol, or C{None} if no protocol has yet been
+        negotiated.
+
+    @ivar _channel: The object capable of behaving like a L{HTTPChannel} that
+        is backing this object. By default this is a L{HTTPChannel}, but if a
+        HTTP protocol upgrade takes place this may be a different channel
+        object. Must implement L{IProtocol}.
+    @type _channel: L{HTTPChannel}
+
+    @ivar _requestFactory: A callable to use to build L{IRequest} objects.
+    @type _requestFactory: L{IRequest}
+
+    @ivar _site: A reference to the creating L{twisted.web.server.Site} object.
+    @type _site: L{twisted.web.server.Site}
+    """
+    _negotiatedProtocol = None
+    _requestFactory = Request
+    _site = None
+
+
+    @property
+    def requestFactory(self):
+        return self._channel.requestFactory
+
+
+    @requestFactory.setter
+    def requestFactory(self, value):
+        self._requestFactory = value
+        self._channel.requestFactory = value
+
+
+    @property
+    def site(self):
+        return self._channel.site
+
+
+    @site.setter
+    def site(self, value):
+        self._site = value
+        self._channel.site = value
+
+
+    def dataReceived(self, data):
+        """
+        A override of L{IProtocol.dataReceived} that checks what protocol we're
+        using.
+        """
+        if self._negotiatedProtocol is None:
+            try:
+                negotiatedProtocol = self._channel.transport.negotiatedProtocol
+            except AttributeError:
+                # Plaintext HTTP, always HTTP/1.1
+                negotiatedProtocol = b'http/1.1'
+
+            if negotiatedProtocol is None:
+                negotiatedProtocol = b'http/1.1'
+
+            if negotiatedProtocol == b'h2':
+                assert H2_ENABLED, "Cannot negotiate HTTP/2 without support."
+            else:
+                # Only HTTP/2 and HTTP/1.1 are supported right now.
+                assert negotiatedProtocol == b'http/1.1', \
+                       "Unsupported protocol negotiated"
+
+            self._negotiatedProtocol = negotiatedProtocol
+
+        return self._channel.dataReceived(data)
+
+
+
+def _genericHTTPChannelProtocolFactory(self):
+    """
+    Returns an appropriately initialized _GenericHTTPChannelProtocol.
+    """
+    return _GenericHTTPChannelProtocol(HTTPChannel())
+
+
+
 class HTTPFactory(protocol.ServerFactory):
     """
     Factory for HTTP server.
@@ -2001,7 +2090,7 @@
         timestamps.
     """
 
-    protocol = HTTPChannel
+    protocol = _genericHTTPChannelProtocolFactory
 
     logPath = None
 

Modified: trunk/twisted/web/test/test_http.py
==============================================================================
--- trunk/twisted/web/test/test_http.py	(original)
+++ trunk/twisted/web/test/test_http.py	Tue Mar 15 09:18:31 2016
@@ -235,6 +235,94 @@
         self.assertEqual(response, expectedResponse)
 
 
+
+class ProtocolNegotiationTests(unittest.TestCase):
+    requests = (
+        b"GET / HTTP/1.1\r\n"
+        b"Accept: text/html\r\n"
+        b"Connection: close\r\n"
+        b"\r\n"
+        b"GET / HTTP/1.0\r\n"
+        b"\r\n")
+
+
+    def _negotiatedProtocolForTransportInstance(self, t):
+        """
+        Run a request using the specific instance of a transport. Returns the
+        negotiated protocol string.
+        """
+        a = http._genericHTTPChannelProtocolFactory(b'')
+        a.requestFactory = DummyHTTPHandler
+        a.makeConnection(t)
+        # one byte at a time, to stress it.
+        for byte in iterbytes(self.requests):
+            a.dataReceived(byte)
+        a.connectionLost(IOError("all done"))
+        return a._negotiatedProtocol
+
+
+    def test_protocolUnspecified(self):
+        """
+        If the transport has no support for protocol negotiation (no
+        negotiatedProtocol attribute), HTTP/1.1 is assumed.
+        """
+        b = StringTransport()
+        negotiatedProtocol = self._negotiatedProtocolForTransportInstance(b)
+        self.assertEqual(negotiatedProtocol, b'http/1.1')
+
+
+    def test_protocolNone(self):
+        """
+        If the transport has no support for protocol negotiation (returns None
+        for negotiatedProtocol), HTTP/1.1 is assumed.
+        """
+        b = StringTransport()
+        b.negotiatedProtocol = None
+        negotiatedProtocol = self._negotiatedProtocolForTransportInstance(b)
+        self.assertEqual(negotiatedProtocol, b'http/1.1')
+
+
+    def test_http11(self):
+        """
+        If the transport reports that HTTP/1.1 is negotiated, that's what's
+        negotiated.
+        """
+        b = StringTransport()
+        b.negotiatedProtocol = b'http/1.1'
+        negotiatedProtocol = self._negotiatedProtocolForTransportInstance(b)
+        self.assertEqual(negotiatedProtocol, b'http/1.1')
+
+
+    def test_http2(self):
+        """
+        If the transport reports that HTTP/2 is negotiated, that's what's
+        negotiated. Currently HTTP/2 is unsupported, so this raises an
+        AssertionError.
+        """
+        b = StringTransport()
+        b.negotiatedProtocol = b'h2'
+        self.assertRaises(
+            AssertionError,
+            self._negotiatedProtocolForTransportInstance,
+            b,
+        )
+
+
+    def test_unknownProtocol(self):
+        """
+        If the transport reports that a protocol other than HTTP/1.1 or HTTP/2
+        is negotiated, an error occurs.
+        """
+        b = StringTransport()
+        b.negotiatedProtocol = b'smtp'
+        self.assertRaises(
+            AssertionError,
+            self._negotiatedProtocolForTransportInstance,
+            b,
+        )
+
+
+
 class HTTPLoopbackTests(unittest.TestCase):
 
     expectedHeaders = {b'request': b'/foo/bar',

Modified: trunk/twisted/web/test/test_web.py
==============================================================================
--- trunk/twisted/web/test/test_web.py	(original)
+++ trunk/twisted/web/test/test_web.py	Tue Mar 15 09:18:31 2016
@@ -320,7 +320,7 @@
         else:
             validator = b"If-Not-Match: " + etag
         for line in [b"GET / HTTP/1.1", validator, b""]:
-            self.channel.lineReceived(line)
+            self.channel.dataReceived(line + b'\r\n')
         result = self.transport.getvalue()
         self.assertEqual(httpCode(result), http.OK)
         self.assertEqual(httpBody(result), b"correct")
@@ -346,7 +346,7 @@
         """
         for line in [b"GET / HTTP/1.1",
                      b"If-Modified-Since: " + http.datetimeToString(100), b""]:
-            self.channel.lineReceived(line)
+            self.channel.dataReceived(line + b'\r\n')
         result = self.transport.getvalue()
         self.assertEqual(httpCode(result), http.NOT_MODIFIED)
         self.assertEqual(httpBody(result), b"")
@@ -414,7 +414,7 @@
         with an empty response body.
         """
         for line in [b"GET / HTTP/1.1", b"If-None-Match: MatchingTag", b""]:
-            self.channel.lineReceived(line)
+            self.channel.dataReceived(line + b'\r\n')
         result = self.transport.getvalue()
         self.assertEqual(httpHeader(result, b"ETag"), b"MatchingTag")
         self.assertEqual(httpCode(result), http.NOT_MODIFIED)
@@ -432,7 +432,7 @@
         """
         for line in [b"GET /with-content-type HTTP/1.1",
                      b"If-None-Match: MatchingTag", b""]:
-            self.channel.lineReceived(line)
+            self.channel.dataReceived(line + b'\r\n')
         result = self.transport.getvalue()
         self.assertEqual(httpCode(result), http.NOT_MODIFIED)
         self.assertEqual(httpBody(result), b"")
@@ -1311,7 +1311,7 @@
         """
         self.site._logDateTime = "[%02d/%3s/%4d:%02d:%02d:%02d +0000]" % (
             25, 'Oct', 2004, 12, 31, 59)
-        self.request.requestHeaders.addRawHeader(b'user-agent', 
+        self.request.requestHeaders.addRawHeader(b'user-agent',
                                                  b'Malicious Web" Evil')
         self.assertLogs(
             b'"1.2.3.4" - - [25/Oct/2004:12:31:59 +0000] '