Cleaned up oauth code based on feedback. Created FlowThreeLegged and OAuthCredentials classes.
diff --git a/httplib2/socks.py b/httplib2/socks.py
new file mode 100644
index 0000000..6f4f020
--- /dev/null
+++ b/httplib2/socks.py
@@ -0,0 +1,439 @@
+"""SocksiPy - Python SOCKS module.
+Version 1.00
+
+Copyright 2006 Dan-Haim. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+3. Neither the name of Dan Haim nor the names of his contributors may be used
+   to endorse or promote products derived from this software without specific
+   prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY DAN HAIM "AS IS" AND ANY EXPRESS OR IMPLIED
+WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+EVENT SHALL DAN HAIM OR HIS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA
+OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+This module provides a standard socket-like interface for Python
+for tunneling connections through SOCKS proxies.
+
+"""
+
+"""
+
+Minor modifications made by Christopher Gilbert (http://motomastyle.com/)
+for use in PyLoris (http://pyloris.sourceforge.net/)
+
+Minor modifications made by Mario Vilas (http://breakingcode.wordpress.com/)
+mainly to merge bug fixes found in Sourceforge
+
+"""
+
+import socket
+import struct
+import sys
+
+if not hasattr(socket, 'socket'):
+  raise ImportError("Running on App Engine?")
+
+PROXY_TYPE_SOCKS4 = 1
+PROXY_TYPE_SOCKS5 = 2
+PROXY_TYPE_HTTP = 3
+
+_defaultproxy = None
+
+# Small hack for Python 2.x
+if sys.version_info[0] <= 2:
+    def bytes(obj, enc=None):
+        return obj
+
+class ProxyError(Exception):
+    def __init__(self, value):
+        self.value = value
+    def __str__(self):
+        return repr(self.value)
+
+class GeneralProxyError(ProxyError):
+    def __init__(self, value):
+        self.value = value
+    def __str__(self):
+        return repr(self.value)
+
+class Socks5AuthError(ProxyError):
+    def __init__(self, value):
+        self.value = value
+    def __str__(self):
+        return repr(self.value)
+
+class Socks5Error(ProxyError):
+    def __init__(self, value):
+        self.value = value
+    def __str__(self):
+        return repr(self.value)
+
+class Socks4Error(ProxyError):
+    def __init__(self, value):
+        self.value = value
+    def __str__(self):
+        return repr(self.value)
+
+class HTTPError(ProxyError):
+    def __init__(self, value):
+        self.value = value
+    def __str__(self):
+        return repr(self.value)
+
+_generalerrors = ("success",
+                  "invalid data",
+                  "not connected",
+                  "not available",
+                  "bad proxy type",
+                  "bad input")
+
+_socks5errors = ("succeeded",
+                 "general SOCKS server failure",
+                 "connection not allowed by ruleset",
+                 "Network unreachable",
+                 "Host unreachable",
+                 "Connection refused",
+                 "TTL expired",
+                 "Command not supported",
+                 "Address type not supported",
+                 "Unknown error")
+
+_socks5autherrors = ("succeeded",
+                     "authentication is required",
+                     "all offered authentication methods were rejected",
+                     "unknown username or invalid password",
+                     "unknown error")
+
+_socks4errors = ("request granted",
+                 "request rejected or failed",
+                 ("request rejected because SOCKS server cannot connect to "
+                  "identd on the client"),
+                 ("request rejected because the client program and identd"
+                  " report different user-ids"),
+                 "unknown error")
+
+
+def setdefaultproxy(proxytype=None, addr=None, port=None, rdns=True,
+                    username=None, password=None):
+    """setdefaultproxy(proxytype, addr[, port[, rdns[, username[, password]]]])
+    Sets a default proxy which all further socksocket objects will use,
+    unless explicitly changed.
+    """
+    global _defaultproxy
+    _defaultproxy = (proxytype, addr, port, rdns, username, password)
+
+
+class socksocket(socket.socket):
+    """socksocket([family[, type[, proto]]]) -> socket object
+
+    Open a SOCKS enabled socket. The parameters are the same as
+    those of the standard socket init. In order for SOCKS to work,
+    you must specify family=AF_INET, type=SOCK_STREAM and proto=0.
+    """
+
+    def __init__(self, family=socket.AF_INET, type=socket.SOCK_STREAM,
+                 proto=0, _sock=None):
+        socket.socket.__init__(self, family, type, proto, _sock)
+        if _defaultproxy != None:
+            self.__proxy = _defaultproxy
+        else:
+            self.__proxy = (None, None, None, None, None, None)
+        self.__proxysockname = None
+        self.__proxypeername = None
+
+    def __decode(self, bytes):
+        if getattr(bytes, 'decode', False):
+            try:
+                bytes = bytes.decode()
+            except Exception:
+                pass
+        return bytes
+
+    def __encode(self, bytes):
+        if getattr(bytes, 'encode', False):
+            try:
+                bytes = bytes.encode()
+            except Exception:
+                pass
+        return bytes
+
+    def __recvall(self, count):
+        """__recvall(count) -> data
+        Receive EXACTLY the number of bytes requested from the socket.
+        Blocks until the required number of bytes have been received.
+        """
+        data = bytes("")
+        while len(data) < count:
+            d = self.recv(count - len(data))
+            if not d:
+                raise GeneralProxyError(
+                    (0, "connection closed unexpectedly"))
+            data = data + self.__decode(d)
+        return data
+
+    def sendall(self, bytes):
+        socket.socket.sendall(self, self.__encode(bytes))
+
+    def setproxy(self, proxytype=None, addr=None, port=None, rdns=True,
+                 username=None, password=None):
+        """setproxy(proxytype, addr[, port[, rdns[, username[, password]]]])
+        Sets the proxy to be used.
+        proxytype -    The type of the proxy to be used. Three types
+                are supported: PROXY_TYPE_SOCKS4 (including socks4a),
+                PROXY_TYPE_SOCKS5 and PROXY_TYPE_HTTP
+        addr -        The address of the server (IP or DNS).
+        port -        The port of the server. Defaults to 1080 for SOCKS
+                servers and 8080 for HTTP proxy servers.
+        rdns -        Should DNS queries be preformed on the remote side
+                (rather than the local side). The default is True.
+                Note: This has no effect with SOCKS4 servers.
+        username -    Username to authenticate with to the server.
+                The default is no authentication.
+        password -    Password to authenticate with to the server.
+                Only relevant when username is also provided.
+        """
+        self.__proxy = (proxytype, addr, port, rdns, username, password)
+
+    def __negotiatesocks5(self, destaddr, destport):
+        """__negotiatesocks5(self,destaddr,destport)
+        Negotiates a connection through a SOCKS5 server.
+        """
+        # First we'll send the authentication packages we support.
+        if (self.__proxy[4] != None) and (self.__proxy[5] != None):
+            # The username/password details were supplied to the
+            # setproxy method so we support the USERNAME/PASSWORD
+            # authentication (in addition to the standard none).
+            self.sendall("\x05\x02\x00\x02")
+        else:
+            # No username/password were entered, therefore we
+            # only support connections with no authentication.
+            self.sendall("\x05\x01\x00")
+        # We'll receive the server's response to determine which
+        # method was selected
+        chosenauth = self.__recvall(2)
+        if chosenauth[0] != "\x05":
+            self.close()
+            raise GeneralProxyError((1, _generalerrors[1]))
+        # Check the chosen authentication method
+        if chosenauth[1] == "\x00":
+            # No authentication is required
+            pass
+        elif chosenauth[1] == "\x02":
+            # Okay, we need to perform a basic username/password
+            # authentication.
+            self.sendall("\x01" + chr(len(self.__proxy[4])) + self.__proxy[4] +
+                         chr(len(self.__proxy[5])) + self.__proxy[5])
+            authstat = self.__recvall(2)
+            if authstat[0] != "\x01":
+                # Bad response
+                self.close()
+                raise GeneralProxyError((1, _generalerrors[1]))
+            if authstat[1] != "\x00":
+                # Authentication failed
+                self.close()
+                raise Socks5AuthError((3, _socks5autherrors[3]))
+            # Authentication succeeded
+        else:
+            # Reaching here is always bad
+            self.close()
+            if chosenauth[1] == "\xFF":
+                raise Socks5AuthError((2, _socks5autherrors[2]))
+            else:
+                raise GeneralProxyError((1, _generalerrors[1]))
+        # Now we can request the actual connection
+        req = "\x05\x01\x00"
+        # If the given destination address is an IP address, we'll
+        # use the IPv4 address request even if remote resolving was specified.
+        try:
+            ipaddr = socket.inet_aton(destaddr)
+            req = req + "\x01" + ipaddr
+        except socket.error:
+            # Well it's not an IP number,  so it's probably a DNS name.
+            if self.__proxy[3] == True:
+                # Resolve remotely
+                ipaddr = None
+                req = req + "\x03" + chr(len(destaddr)) + destaddr
+            else:
+                # Resolve locally
+                ipaddr = socket.inet_aton(socket.gethostbyname(destaddr))
+                req = req + "\x01" + ipaddr
+        req = req + self.__decode(struct.pack(">H", destport))
+        self.sendall(req)
+        # Get the response
+        resp = self.__recvall(4)
+        if resp[0] != "\x05":
+            self.close()
+            raise GeneralProxyError((1, _generalerrors[1]))
+        elif resp[1] != "\x00":
+            # Connection failed
+            self.close()
+            if ord(resp[1]) <= 8:
+                raise Socks5Error((ord(resp[1]), _socks5errors[ord(resp[1])]))
+            else:
+                raise Socks5Error((9, _socks5errors[9]))
+        # Get the bound address/port
+        elif resp[3] == "\x01":
+            boundaddr = self.__recvall(4)
+        elif resp[3] == "\x03":
+            resp = resp + self.recv(1)
+            boundaddr = self.__recvall(ord(resp[4]))
+        else:
+            self.close()
+            raise GeneralProxyError((1, _generalerrors[1]))
+        boundport = struct.unpack(">H", bytes(self.__recvall(2), 'utf8'))[0]
+        self.__proxysockname = boundaddr, boundport
+        if ipaddr != None:
+            self.__proxypeername = (socket.inet_ntoa(ipaddr), destport)
+        else:
+            self.__proxypeername = (destaddr, destport)
+
+    def getproxysockname(self):
+        """getsockname() -> address info
+        Returns the bound IP address and port number at the proxy.
+        """
+        return self.__proxysockname
+
+    def getproxypeername(self):
+        """getproxypeername() -> address info
+        Returns the IP and port number of the proxy.
+        """
+        return socket.socket.getpeername(self)
+
+    def getpeername(self):
+        """getpeername() -> address info
+        Returns the IP address and port number of the destination
+        machine (note: getproxypeername returns the proxy)
+        """
+        return self.__proxypeername
+
+    def __negotiatesocks4(self, destaddr, destport):
+        """__negotiatesocks4(self,destaddr,destport)
+        Negotiates a connection through a SOCKS4 server.
+        """
+        # Check if the destination address provided is an IP address
+        rmtrslv = False
+        try:
+            ipaddr = socket.inet_aton(destaddr)
+        except socket.error:
+            # It's a DNS name. Check where it should be resolved.
+            if self.__proxy[3] == True:
+                ipaddr = "\x00\x00\x00\x01"
+                rmtrslv = True
+            else:
+                ipaddr = socket.inet_aton(socket.gethostbyname(destaddr))
+        # Construct the request packet
+        req = "\x04\x01" + self.__decode(struct.pack(">H", destport)) + ipaddr
+        # The username parameter is considered userid for SOCKS4
+        if self.__proxy[4] != None:
+            req = req + self.__proxy[4]
+        req = req + "\x00"
+        # DNS name if remote resolving is required
+        # NOTE: This is actually an extension to the SOCKS4 protocol
+        # called SOCKS4A and may not be supported in all cases.
+        if rmtrslv==True:
+            req = req + destaddr + "\x00"
+        self.sendall(req)
+        # Get the response from the server
+        resp = self.__recvall(8)
+        if resp[0] != "\x00":
+            # Bad data
+            self.close()
+            raise GeneralProxyError((1, _generalerrors[1]))
+        if resp[1] != "\x5A":
+            # Server returned an error
+            self.close()
+            if ord(resp[1]) in (91,92,93):
+                self.close()
+                raise Socks4Error((ord(resp[1]), _socks4errors[ord(resp[1])-90]))
+            else:
+                raise Socks4Error((94,_socks4errors[4]))
+        # Get the bound address/port
+        self.__proxysockname = (socket.inet_ntoa(resp[4:]),struct.unpack(">H",bytes(resp[2:4],'utf8'))[0])
+        if rmtrslv != None:
+            self.__proxypeername = (socket.inet_ntoa(ipaddr),destport)
+        else:
+            self.__proxypeername = (destaddr, destport)
+
+    def __negotiatehttp(self, destaddr, destport):
+        """__negotiatehttp(self,destaddr,destport)
+        Negotiates a connection through an HTTP server.
+        """
+        # If we need to resolve locally, we do this now
+        if self.__proxy[3] == False:
+            addr = socket.gethostbyname(destaddr)
+        else:
+            addr = destaddr
+        self.sendall(("CONNECT %s:%s HTTP/1.1\r\n"
+                      "Host: %s\r\n\r\n") % (addr, destport, destaddr))
+        # We read the response until we get the string "\r\n\r\n"
+        resp = self.recv(1)
+        while resp.find("\r\n\r\n") == -1:
+            resp = resp + self.recv(1)
+        # We just need the first line to check if the connection
+        # was successful
+        statusline = resp.splitlines()[0].split(" ", 2)
+        if statusline[0] not in ("HTTP/1.0", "HTTP/1.1"):
+            self.close()
+            raise GeneralProxyError((1, _generalerrors[1]))
+        try:
+            statuscode = int(statusline[1])
+        except ValueError:
+            self.close()
+            raise GeneralProxyError((1, _generalerrors[1]))
+        if statuscode != 200:
+            self.close()
+            raise HTTPError((statuscode, statusline[2]))
+        self.__proxysockname = ("0.0.0.0", 0)
+        self.__proxypeername = (addr, destport)
+
+    def connect(self, destpair):
+        """connect(self,despair)
+        Connects to the specified destination through a proxy.
+        destpar - A tuple of the IP/DNS address and the port number.
+        (identical to socket's connect).
+        To select the proxy server use setproxy().
+        """
+        # Do a minimal input check first
+        # TODO(durin42): seriously? type checking? do we care?
+        if ((not isinstance(destpair, (list, tuple))) or len(destpair) < 2
+            or not isinstance(destpair[0], str) or not isinstance(destpair[1], int)):
+            raise GeneralProxyError((5, _generalerrors[5]))
+        if self.__proxy[0] == PROXY_TYPE_SOCKS5:
+            if self.__proxy[2] != None:
+                portnum = self.__proxy[2]
+            else:
+                portnum = 1080
+            socket.socket.connect(self,(self.__proxy[1], portnum))
+            self.__negotiatesocks5(destpair[0], destpair[1])
+        elif self.__proxy[0] == PROXY_TYPE_SOCKS4:
+            if self.__proxy[2] != None:
+                portnum = self.__proxy[2]
+            else:
+                portnum = 1080
+            socket.socket.connect(self, (self.__proxy[1], portnum))
+            self.__negotiatesocks4(destpair[0], destpair[1])
+        elif self.__proxy[0] == PROXY_TYPE_HTTP:
+            if self.__proxy[2] != None:
+                portnum = self.__proxy[2]
+            else:
+                portnum = 8080
+            socket.socket.connect(self, (self.__proxy[1], portnum))
+            self.__negotiatehttp(destpair[0], destpair[1])
+        elif self.__proxy[0] == None:
+            socket.socket.connect(self, (destpair[0], destpair[1]))
+        else:
+            raise GeneralProxyError((4, _generalerrors[4]))