websockets: Add websockets13 support

1 files changed, 420 insertions, 34 deletions

diff --git a/eventlet/websocket.py b/eventlet/websocket.py
index 4ba20c4..d99206e 100644
--- a/eventlet/websocket.py
+++ b/eventlet/websocket.py
@@ -1,13 +1,19 @@
+import base64
+import codecs
 import collections
 import errno
+from random import Random
 import string
 import struct
+import sys
+import time
 from socket import error as SocketError
 
 try:
-    from hashlib import md5
+    from hashlib import md5, sha1
 except ImportError: #pragma NO COVER
     from md5 import md5
+    from sha import sha as sha1
 
 import eventlet
 from eventlet import semaphore
@@ -15,9 +21,41 @@ from eventlet import wsgi
 from eventlet.green import socket
 from eventlet.support import get_errno
 
+# Python 2's utf8 decoding is more lenient than we'd like
+# In order to pass autobahn's testsuite we need stricter validation
+# if available...
+for _mod in ('wsaccel.utf8validator', 'autobahn.utf8validator'):
+    # autobahn has it's own python-based validator. in newest versions
+    # this prefers to use wsaccel, a cython based implementation, if available.
+    # wsaccel may also be installed w/out autobahn, or with a earlier version.
+    try:
+        utf8validator = __import__(_mod, {}, {}, [''])
+    except ImportError:
+        utf8validator = None
+    else:
+        break
+
 ACCEPTABLE_CLIENT_ERRORS = set((errno.ECONNRESET, errno.EPIPE))
 
 __all__ = ["WebSocketWSGI", "WebSocket"]
+PROTOCOL_GUID = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
+VALID_CLOSE_STATUS = (range(1000, 1004)
+                      + range(1007, 1012)
+                      # 3000-3999: reserved for use by libraries, frameworks,
+                      # and applications
+                      + range(3000, 4000)
+                      # 4000-4999: reserved for private use and thus can't
+                      # be registered
+                      + range(4000, 5000))
+
+
+class BadRequest(Exception):
+    def __init__(self, status='400 Bad Request', body=None, headers=None):
+        super(Exception, self).__init__()
+        self.status = status
+        self.body = body
+        self.headers = headers
+
 
 class WebSocketWSGI(object):
     """Wraps a websocket handler function in a WSGI application.
@@ -37,29 +75,70 @@ class WebSocketWSGI(object):
     def __init__(self, handler):
         self.handler = handler
         self.protocol_version = None
+        self.support_legacy_versions = True
+        self.supported_protocols = []
+        self.origin_checker = None
+
+    @classmethod
+    def configured(cls,
+                   handler=None,
+                   supported_protocols=None,
+                   origin_checker=None,
+                   support_legacy_versions=False):
+        def decorator(handler):
+            inst = cls(handler)
+            inst.support_legacy_versions = support_legacy_versions
+            inst.origin_checker = origin_checker
+            if supported_protocols:
+                inst.supported_protocols = supported_protocols
+            return inst
+        if handler is None:
+            return decorator
+        return decorator(handler)
 
     def __call__(self, environ, start_response):
         if not (environ.get('HTTP_CONNECTION') == 'Upgrade' and
                 environ.get('HTTP_UPGRADE').lower() == 'websocket'):
             # need to check a few more things here for true compliance
-            start_response('400 Bad Request', [('Connection','close')])
+            start_response('400 Bad Request', [('Connection', 'close')])
             return []
-    
-        # See if they sent the new-format headers
+
+        try:
+            if 'HTTP_SEC_WEBSOCKET_VERSION' in environ:
+                ws = self._handle_hybi_request(environ)
+            elif self.support_legacy_versions:
+                ws = self._handle_legacy_request(environ)
+            else:
+                raise BadRequest()
+        except BadRequest, e:
+            status = e.status
+            body = e.body or ''
+            headers = e.headers or []
+            start_response(status,
+                           [('Connection', 'close'), ] + headers)
+            return [body]
+
+        try:
+            self.handler(ws)
+        except socket.error, e:
+            if get_errno(e) not in ACCEPTABLE_CLIENT_ERRORS:
+                raise
+        # Make sure we send the closing frame
+        ws._send_closing_frame(True)
+        # use this undocumented feature of eventlet.wsgi to ensure that it
+        # doesn't barf on the fact that we didn't call start_response
+        return wsgi.ALREADY_HANDLED
+
+    def _handle_legacy_request(self, environ):
+        sock = environ['eventlet.input'].get_socket()
+
         if 'HTTP_SEC_WEBSOCKET_KEY1' in environ:
             self.protocol_version = 76
             if 'HTTP_SEC_WEBSOCKET_KEY2' not in environ:
-                # That's bad.
-                start_response('400 Bad Request', [('Connection','close')])
-                return []
+                raise BadRequest()
         else:
             self.protocol_version = 75
 
-        # Get the underlying socket and wrap a WebSocket class around it
-        sock = environ['eventlet.input'].get_socket()
-        ws = WebSocket(sock, environ, self.protocol_version)
-        
-        # If it's new-version, we need to work out our challenge response
         if self.protocol_version == 76:
             key1 = self._extract_number(environ['HTTP_SEC_WEBSOCKET_KEY1'])
             key2 = self._extract_number(environ['HTTP_SEC_WEBSOCKET_KEY2'])
@@ -69,15 +148,15 @@ class WebSocketWSGI(object):
             key3 = environ['wsgi.input'].read(8)
             key = struct.pack(">II", key1, key2) + key3
             response = md5(key).digest()
-        
+
         # Start building the response
         scheme = 'ws'
         if environ.get('wsgi.url_scheme') == 'https':
             scheme = 'wss'
         location = '%s://%s%s%s' % (
             scheme,
-            environ.get('HTTP_HOST'), 
-            environ.get('SCRIPT_NAME'), 
+            environ.get('HTTP_HOST'),
+            environ.get('SCRIPT_NAME'),
             environ.get('PATH_INFO')
         )
         qs = environ.get('QUERY_STRING')
@@ -98,25 +177,56 @@ class WebSocketWSGI(object):
                                "Sec-WebSocket-Origin: %s\r\n"
                                "Sec-WebSocket-Protocol: %s\r\n"
                                "Sec-WebSocket-Location: %s\r\n"
-                               "\r\n%s"% (
+                               "\r\n%s" % (
                     environ.get('HTTP_ORIGIN'),
                     environ.get('HTTP_SEC_WEBSOCKET_PROTOCOL', 'default'),
                     location,
                     response))
         else: #pragma NO COVER
             raise ValueError("Unknown WebSocket protocol version.") 
-        
         sock.sendall(handshake_reply)
-        try:
-            self.handler(ws)
-        except socket.error as e:
-            if get_errno(e) not in ACCEPTABLE_CLIENT_ERRORS:
-                raise
-        # Make sure we send the closing frame
-        ws._send_closing_frame(True)
-        # use this undocumented feature of eventlet.wsgi to ensure that it
-        # doesn't barf on the fact that we didn't call start_response
-        return wsgi.ALREADY_HANDLED
+        return WebSocket(sock, environ, self.protocol_version)
+
+    def _handle_hybi_request(self, environ):
+        sock = environ['eventlet.input'].get_socket()
+        hybi_version = environ['HTTP_SEC_WEBSOCKET_VERSION']
+        if hybi_version not in ('8', '13', ):
+            raise BadRequest(status='426 Upgrade Required',
+                             headers=[('Sec-WebSocket-Version', '8, 13')])
+        self.protocol_version = int(hybi_version)
+        if 'HTTP_SEC_WEBSOCKET_KEY' not in environ:
+            # That's bad.
+            raise BadRequest()
+        origin = environ.get(
+            'HTTP_ORIGIN',
+            (environ.get('HTTP_SEC_WEBSOCKET_ORIGIN', '')
+             if self.protocol_version <= 8 else ''))
+        if self.origin_checker is not None:
+            if not self.origin_checker(environ.get('HTTP_HOST'), origin):
+                raise BadRequest(status='403 Forbidden')
+        protocols = environ.get('HTTP_SEC_WEBSOCKET_PROTOCOL', None)
+        negotiated_protocol = None
+        if protocols:
+            for p in (i.strip() for i in protocols.split(',')):
+                if p in self.supported_protocols:
+                    negotiated_protocol = p
+                    break
+        #extensions = environ.get('HTTP_SEC_WEBSOCKET_EXTENSIONS', None)
+        #if extensions:
+        #    extensions = [i.strip() for i in extensions.split(',')]
+
+        key = environ['HTTP_SEC_WEBSOCKET_KEY']
+        response = base64.b64encode(sha1(key + PROTOCOL_GUID).digest())
+        handshake_reply = ["HTTP/1.1 101 Switching Protocols",
+                           "Upgrade: websocket",
+                           "Connection: Upgrade",
+                           "Sec-WebSocket-Accept: %s" % (response, )]
+        if negotiated_protocol:
+            handshake_reply.append("Sec-WebSocket-Protocol: %s"
+                                   % (negotiated_protocol, ))
+        sock.sendall('\r\n'.join(handshake_reply) + '\r\n\r\n')
+        return RFC6455WebSocket(sock, environ, self.protocol_version,
+                                protocol=negotiated_protocol)
 
     def _extract_number(self, value):
         """
@@ -135,12 +245,12 @@ class WebSocketWSGI(object):
 class WebSocket(object):
     """A websocket object that handles the details of
     serialization/deserialization to the socket.
-    
+
     The primary way to interact with a :class:`WebSocket` object is to
     call :meth:`send` and :meth:`wait` in order to pass messages back
     and forth with the browser.  Also available are the following
     properties:
-    
+
     path
         The path value of the request.  This is the same as the WSGI PATH_INFO variable, but more convenient.
     protocol
@@ -210,10 +320,10 @@ class WebSocket(object):
                 raise ValueError("Don't understand how to parse this type of message: %r" % buf)
         self._buf = buf
         return msgs
-    
+
     def send(self, message):
-        """Send a message to the browser.  
-        
+        """Send a message to the browser.
+
         *message* should be convertable to a string; unicode objects should be
         encodable as utf-8.  Raises socket.error with errno of 32
         (broken pipe) if the socket has already been closed by the client."""
@@ -227,8 +337,8 @@ class WebSocket(object):
             self._sendlock.release()
 
     def wait(self):
-        """Waits for and deserializes messages. 
-        
+        """Waits for and deserializes messages.
+
         Returns a single message; the oldest not yet processed. If the client
         has already closed the connection, returns None.  This is different
         from normal socket behavior because the empty string is a valid
@@ -265,3 +375,279 @@ class WebSocket(object):
         self.socket.shutdown(True)
         self.socket.close()
 
+
+class ConnectionClosedError(Exception):
+    pass
+
+
+class FailedConnectionError(Exception):
+    def __init__(self, status, message):
+        super(FailedConnectionError, self).__init__(status, message)
+        self.message = message
+        self.status = status
+
+
+class ProtocolError(ValueError):
+    pass
+
+
+class RFC6455WebSocket(WebSocket):
+    def __init__(self, sock, environ, version=13, protocol=None, client=False):
+        super(RFC6455WebSocket, self).__init__(sock, environ, version)
+        self.iterator = self._iter_frames()
+        self.client = client
+        self.protocol = protocol
+
+    class UTF8Decoder(object):
+        def __init__(self):
+            if utf8validator:
+                self.validator = utf8validator.Utf8Validator()
+            else:
+                self.validator = None
+            decoderclass = codecs.getincrementaldecoder('utf8')
+            self.decoder = decoderclass()
+
+        def reset(self):
+            if self.validator:
+                self.validator.reset()
+            self.decoder.reset()
+
+        def decode(self, data, final=False):
+            if self.validator:
+                valid, eocp, c_i, t_i = self.validator.validate(data)
+                if not valid:
+                    raise ValueError('Data is not valid unicode')
+            return self.decoder.decode(data, final)
+
+    def _get_bytes(self, numbytes):
+        data = ''
+        while len(data) < numbytes:
+            d = self.socket.recv(numbytes - len(data))
+            if not d:
+                raise ConnectionClosedError()
+            data = data + d
+        return data
+
+    class Message(object):
+        def __init__(self, opcode, decoder=None):
+            self.decoder = decoder
+            self.data = []
+            self.finished = False
+            self.opcode = opcode
+
+        def push(self, data, final=False):
+            if self.decoder:
+                data = self.decoder.decode(data, final=final)
+            self.finished = final
+            self.data.append(data)
+
+        def getvalue(self):
+            return ''.join(self.data)
+
+    @staticmethod
+    def _apply_mask(data, mask, length=None, offset=0):
+        if length is None:
+            length = len(data)
+        cnt = xrange(length)
+        return ''.join(chr(ord(data[i]) ^ mask[(offset + i) % 4]) for i in cnt)
+
+    def _handle_control_frame(self, opcode, data):
+        if opcode == 8:  # connection close
+            if not data:
+                status = 1000
+            elif len(data) > 1:
+                status = struct.unpack_from('!H', data)[0]
+                if not status or status not in VALID_CLOSE_STATUS:
+                    raise FailedConnectionError(
+                        1002,
+                        "Unexpected close status code.")
+                try:
+                    data = self.UTF8Decoder().decode(data[2:], True)
+                except (UnicodeDecodeError, ValueError):
+                    raise FailedConnectionError(
+                        1002,
+                        "Close message data should be valid UTF-8.")
+            else:
+                status = 1002
+            self.close(close_data=(status, ''))
+            raise ConnectionClosedError()
+        elif opcode == 9:  # ping
+            self.send(data, control_code=0xA)
+        elif opcode == 0xA:  # pong
+            pass
+        else:
+            raise FailedConnectionError(
+                1002, "Unknown control frame received.")
+
+    def _iter_frames(self):
+        fragmented_message = None
+        try:
+            while True:
+                message = self._recv_frame(message=fragmented_message)
+                if message.opcode & 8:
+                    self._handle_control_frame(
+                        message.opcode, message.getvalue())
+                    continue
+                if fragmented_message and message is not fragmented_message:
+                    raise RuntimeError('Unexpected message change.')
+                fragmented_message = message
+                if message.finished:
+                    data = fragmented_message.getvalue()
+                    fragmented_message = None
+                    yield data
+        except FailedConnectionError:
+            exc_typ, exc_val, exc_tb = sys.exc_info()
+            self.close(close_data=(exc_val.status, exc_val.message))
+        except ConnectionClosedError:
+            return
+        except Exception:
+            self.close(close_data=(1011, 'Internal Server Error'))
+            raise
+
+    def _recv_frame(self, message=None):
+        recv = self._get_bytes
+        header = recv(2)
+        a, b = struct.unpack('!BB', header)
+        finished = a >> 7 == 1
+        rsv123 = a >> 4 & 7
+        if rsv123:
+            # must be zero
+            raise FailedConnectionError(
+                1002,
+                "RSV1, RSV2, RSV3: MUST be 0 unless an extension is"
+                " negotiated that defines meanings for non-zero values.")
+        opcode = a & 15
+        if opcode not in (0, 1, 2, 8, 9, 0xA):
+            raise FailedConnectionError(1002, "Unknown opcode received.")
+        masked = b & 128 == 128
+        if not masked and not self.client:
+            raise FailedConnectionError(1002, "A client MUST mask all frames"
+                                        " that it sends to the server")
+        length = b & 127
+        if opcode & 8:
+            if not finished:
+                raise FailedConnectionError(1002, "Control frames must not"
+                                            " be fragmented.")
+            if length > 125:
+                raise FailedConnectionError(
+                    1002,
+                    "All control frames MUST have a payload length of 125"
+                    " bytes or less")
+        elif opcode and message:
+            raise FailedConnectionError(
+                1002,
+                "Received a non-continuation opcode within"
+                " fragmented message.")
+        elif not opcode and not message:
+            raise FailedConnectionError(
+                1002,
+                "Received continuation opcode with no previous"
+                " fragments received.")
+        if length == 126:
+            length = struct.unpack('!H', recv(2))[0]
+        elif length == 127:
+            length = struct.unpack('!Q', recv(8))[0]
+        if masked:
+            mask = struct.unpack('!BBBB', recv(4))
+        received = 0
+        if not message or opcode & 8:
+            decoder = self.UTF8Decoder() if opcode == 1 else None
+            message = self.Message(opcode, decoder=decoder)
+        if not length:
+            message.push('', final=finished)
+        else:
+            while received < length:
+                d = self.socket.recv(length - received)
+                if not d:
+                    raise ConnectionClosedError()
+                dlen = len(d)
+                if masked:
+                    d = self._apply_mask(d, mask, length=dlen, offset=received)
+                received = received + dlen
+                try:
+                    message.push(d, final=finished)
+                except (UnicodeDecodeError, ValueError):
+                    raise FailedConnectionError(
+                        1007, "Text data must be valid utf-8")
+        return message
+
+    @staticmethod
+    def _pack_message(message, masked=False,
+                      continuation=False, final=True, control_code=None):
+        is_text = False
+        if isinstance(message, unicode):
+            message = message.encode('utf-8')
+            is_text = True
+        length = len(message)
+        if not length:
+            # no point masking empty data
+            masked = False
+        if control_code:
+            if control_code not in (8, 9, 0xA):
+                raise ProtocolError('Unknown control opcode.')
+            if continuation or not final:
+                raise ProtocolError('Control frame cannot be a fragment.')
+            if length > 125:
+                raise ProtocolError('Control frame data too large (>125).')
+            header = struct.pack('!B', control_code | 1 << 7)
+        else:
+            opcode = 0 if continuation else (1 if is_text else 2)
+            header = struct.pack('!B', opcode | (1 << 7 if final else 0))
+        lengthdata = 1 << 7 if masked else 0
+        if length > 65535:
+            lengthdata = struct.pack('!BQ', lengthdata | 127, length)
+        elif length > 125:
+            lengthdata = struct.pack('!BH', lengthdata | 126, length)
+        else:
+            lengthdata = struct.pack('!B', lengthdata | length)
+        if masked:
+            # NOTE: RFC6455 states:
+            # A server MUST NOT mask any frames that it sends to the client
+            rand = Random(time.time())
+            mask = map(rand.getrandbits, (8, ) * 4)
+            message = RFC6455WebSocket._apply_mask(message, mask, length)
+            maskdata = struct.pack('!BBBB', *mask)
+        else:
+            maskdata = ''
+        return ''.join((header, lengthdata, maskdata, message))
+
+    def wait(self):
+        for i in self.iterator:
+            return i
+
+    def _send(self, frame):
+        self._sendlock.acquire()
+        try:
+            self.socket.sendall(frame)
+        finally:
+            self._sendlock.release()
+
+    def send(self, message, **kw):
+        kw['masked'] = self.client
+        payload = self._pack_message(message, **kw)
+        self._send(payload)
+
+    def _send_closing_frame(self, ignore_send_errors=False, close_data=None):
+        if self.version in (8, 13) and not self.websocket_closed:
+            if close_data is not None:
+                status, msg = close_data
+                if isinstance(msg, unicode):
+                    msg = msg.encode('utf-8')
+                data = struct.pack('!H', status) + msg
+            else:
+                data = ''
+            try:
+                self.send(data, control_code=8)
+            except SocketError:
+                # Sometimes, like when the remote side cuts off the connection,
+                # we don't care about this.
+                if not ignore_send_errors:  # pragma NO COVER
+                    raise
+            self.websocket_closed = True
+
+    def close(self, close_data=None):
+        """Forcibly close the websocket; generally it is preferable to
+        return from the handler method."""
+        self._send_closing_frame(close_data=close_data)
+        self.socket.shutdown(socket.SHUT_WR)
+        self.socket.close()