new file mode 100644
--- /dev/null
+++ b/examples/trac/trac/web/_fcgi.py
@@ -0,0 +1,1306 @@
+# -*- coding: iso-8859-1 -*-
+#
+# Copyright (c) 2002, 2003, 2005 Allan Saddi <allan@saddi.com>
+# All rights reserved.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at http://trac.edgewall.com/license.html.
+#
+# This software consists of voluntary contributions made by many
+# individuals. For the exact contribution history, see the revision
+# history and logs, available at http://projects.edgewall.com/trac/.
+#
+# Author: Allan Saddi <allan@saddi.com>
+
+"""
+fcgi - a FastCGI/WSGI gateway.
+
+For more information about FastCGI, see <http://www.fastcgi.com/>.
+
+For more information about the Web Server Gateway Interface, see
+<http://www.python.org/peps/pep-0333.html>.
+
+Example usage:
+
+  #!/usr/bin/env python
+  from myapplication import app # Assume app is your WSGI application object
+  from fcgi import WSGIServer
+  WSGIServer(app).run()
+
+See the documentation for WSGIServer/Server for more information.
+
+On most platforms, fcgi will fallback to regular CGI behavior if run in a
+non-FastCGI context. If you want to force CGI behavior, set the environment
+variable FCGI_FORCE_CGI to "Y" or "y".
+"""
+
+__author__ = 'Allan Saddi <allan@saddi.com>'
+__version__ = '$Revision: 1797 $'
+
+import sys
+import os
+import signal
+import struct
+import StringIO
+import select
+import socket
+import errno
+import traceback
+
+try:
+    import thread
+    import threading
+    thread_available = True
+except ImportError:
+    import dummy_thread as thread
+    import dummy_threading as threading
+    thread_available = False
+
+__all__ = ['WSGIServer']
+
+# Constants from the spec.
+FCGI_LISTENSOCK_FILENO = 0
+
+FCGI_HEADER_LEN = 8
+
+FCGI_VERSION_1 = 1
+
+FCGI_BEGIN_REQUEST = 1
+FCGI_ABORT_REQUEST = 2
+FCGI_END_REQUEST = 3
+FCGI_PARAMS = 4
+FCGI_STDIN = 5
+FCGI_STDOUT = 6
+FCGI_STDERR = 7
+FCGI_DATA = 8
+FCGI_GET_VALUES = 9
+FCGI_GET_VALUES_RESULT = 10
+FCGI_UNKNOWN_TYPE = 11
+FCGI_MAXTYPE = FCGI_UNKNOWN_TYPE
+
+FCGI_NULL_REQUEST_ID = 0
+
+FCGI_KEEP_CONN = 1
+
+FCGI_RESPONDER = 1
+FCGI_AUTHORIZER = 2
+FCGI_FILTER = 3
+
+FCGI_REQUEST_COMPLETE = 0
+FCGI_CANT_MPX_CONN = 1
+FCGI_OVERLOADED = 2
+FCGI_UNKNOWN_ROLE = 3
+
+FCGI_MAX_CONNS = 'FCGI_MAX_CONNS'
+FCGI_MAX_REQS = 'FCGI_MAX_REQS'
+FCGI_MPXS_CONNS = 'FCGI_MPXS_CONNS'
+
+FCGI_Header = '!BBHHBx'
+FCGI_BeginRequestBody = '!HB5x'
+FCGI_EndRequestBody = '!LB3x'
+FCGI_UnknownTypeBody = '!B7x'
+
+FCGI_EndRequestBody_LEN = struct.calcsize(FCGI_EndRequestBody)
+FCGI_UnknownTypeBody_LEN = struct.calcsize(FCGI_UnknownTypeBody)
+
+if __debug__:
+    import time
+
+    # Set non-zero to write debug output to a file.
+    DEBUG = 0
+    DEBUGLOG = '/tmp/fcgi.log'
+
+    def _debug(level, msg):
+        if DEBUG < level:
+            return
+
+        try:
+            f = open(DEBUGLOG, 'a')
+            f.write('%sfcgi: %s\n' % (time.ctime()[4:-4], msg))
+            f.close()
+        except:
+            pass
+
+class InputStream(object):
+    """
+    File-like object representing FastCGI input streams (FCGI_STDIN and
+    FCGI_DATA). Supports the minimum methods required by WSGI spec.
+    """
+    def __init__(self, conn):
+        self._conn = conn
+
+        # See Server.
+        self._shrinkThreshold = conn.server.inputStreamShrinkThreshold
+
+        self._buf = ''
+        self._bufList = []
+        self._pos = 0 # Current read position.
+        self._avail = 0 # Number of bytes currently available.
+
+        self._eof = False # True when server has sent EOF notification.
+
+    def _shrinkBuffer(self):
+        """Gets rid of already read data (since we can't rewind)."""
+        if self._pos >= self._shrinkThreshold:
+            self._buf = self._buf[self._pos:]
+            self._avail -= self._pos
+            self._pos = 0
+
+            assert self._avail >= 0
+
+    def _waitForData(self):
+        """Waits for more data to become available."""
+        self._conn.process_input()
+
+    def read(self, n=-1):
+        if self._pos == self._avail and self._eof:
+            return ''
+        while True:
+            if n < 0 or (self._avail - self._pos) < n:
+                # Not enough data available.
+                if self._eof:
+                    # And there's no more coming.
+                    newPos = self._avail
+                    break
+                else:
+                    # Wait for more data.
+                    self._waitForData()
+                    continue
+            else:
+                newPos = self._pos + n
+                break
+        # Merge buffer list, if necessary.
+        if self._bufList:
+            self._buf += ''.join(self._bufList)
+            self._bufList = []
+        r = self._buf[self._pos:newPos]
+        self._pos = newPos
+        self._shrinkBuffer()
+        return r
+
+    def readline(self, length=None):
+        if self._pos == self._avail and self._eof:
+            return ''
+        while True:
+            # Unfortunately, we need to merge the buffer list early.
+            if self._bufList:
+                self._buf += ''.join(self._bufList)
+                self._bufList = []
+            # Find newline.
+            i = self._buf.find('\n', self._pos)
+            if i < 0:
+                # Not found?
+                if self._eof:
+                    # No more data coming.
+                    newPos = self._avail
+                    break
+                else:
+                    # Wait for more to come.
+                    self._waitForData()
+                    continue
+            else:
+                newPos = i + 1
+                break
+        if length is not None:
+            if self._pos + length < newPos:
+                newPos = self._pos + length
+        r = self._buf[self._pos:newPos]
+        self._pos = newPos
+        self._shrinkBuffer()
+        return r
+
+    def readlines(self, sizehint=0):
+        total = 0
+        lines = []
+        line = self.readline()
+        while line:
+            lines.append(line)
+            total += len(line)
+            if 0 < sizehint <= total:
+                break
+            line = self.readline()
+        return lines
+
+    def __iter__(self):
+        return self
+
+    def next(self):
+        r = self.readline()
+        if not r:
+            raise StopIteration
+        return r
+
+    def add_data(self, data):
+        if not data:
+            self._eof = True
+        else:
+            self._bufList.append(data)
+            self._avail += len(data)
+
+class MultiplexedInputStream(InputStream):
+    """
+    A version of InputStream meant to be used with MultiplexedConnections.
+    Assumes the MultiplexedConnection (the producer) and the Request
+    (the consumer) are running in different threads.
+    """
+    def __init__(self, conn):
+        super(MultiplexedInputStream, self).__init__(conn)
+
+        # Arbitrates access to this InputStream (it's used simultaneously
+        # by a Request and its owning Connection object).
+        lock = threading.RLock()
+
+        # Notifies Request thread that there is new data available.
+        self._lock = threading.Condition(lock)
+
+    def _waitForData(self):
+        # Wait for notification from add_data().
+        self._lock.wait()
+
+    def read(self, n=-1):
+        self._lock.acquire()
+        try:
+            return super(MultiplexedInputStream, self).read(n)
+        finally:
+            self._lock.release()
+
+    def readline(self, length=None):
+        self._lock.acquire()
+        try:
+            return super(MultiplexedInputStream, self).readline(length)
+        finally:
+            self._lock.release()
+
+    def add_data(self, data):
+        self._lock.acquire()
+        try:
+            super(MultiplexedInputStream, self).add_data(data)
+            self._lock.notify()
+        finally:
+            self._lock.release()
+
+class OutputStream(object):
+    """
+    FastCGI output stream (FCGI_STDOUT/FCGI_STDERR). By default, calls to
+    write() or writelines() immediately result in Records being sent back
+    to the server. Buffering should be done in a higher level!
+    """
+    def __init__(self, conn, req, type, buffered=False):
+        self._conn = conn
+        self._req = req
+        self._type = type
+        self._buffered = buffered
+        self._bufList = [] # Used if buffered is True
+        self.dataWritten = False
+        self.closed = False
+
+    def _write(self, data):
+        length = len(data)
+        while length:
+            toWrite = min(length, self._req.server.maxwrite - FCGI_HEADER_LEN)
+
+            rec = Record(self._type, self._req.requestId)
+            rec.contentLength = toWrite
+            rec.contentData = data[:toWrite]
+            self._conn.writeRecord(rec)
+
+            data = data[toWrite:]
+            length -= toWrite
+
+    def write(self, data):
+        assert not self.closed
+
+        if not data:
+            return
+
+        self.dataWritten = True
+
+        if self._buffered:
+            self._bufList.append(data)
+        else:
+            self._write(data)
+
+    def writelines(self, lines):
+        assert not self.closed
+
+        for line in lines:
+            self.write(line)
+
+    def flush(self):
+        # Only need to flush if this OutputStream is actually buffered.
+        if self._buffered:
+            data = ''.join(self._bufList)
+            self._bufList = []
+            self._write(data)
+
+    # Though available, the following should NOT be called by WSGI apps.
+    def close(self):
+        """Sends end-of-stream notification, if necessary."""
+        if not self.closed and self.dataWritten:
+            self.flush()
+            rec = Record(self._type, self._req.requestId)
+            self._conn.writeRecord(rec)
+            self.closed = True
+
+class TeeOutputStream(object):
+    """
+    Simple wrapper around two or more output file-like objects that copies
+    written data to all streams.
+    """
+    def __init__(self, streamList):
+        self._streamList = streamList
+
+    def write(self, data):
+        for f in self._streamList:
+            f.write(data)
+
+    def writelines(self, lines):
+        for line in lines:
+            self.write(line)
+
+    def flush(self):
+        for f in self._streamList:
+            f.flush()
+
+class StdoutWrapper(object):
+    """
+    Wrapper for sys.stdout so we know if data has actually been written.
+    """
+    def __init__(self, stdout):
+        self._file = stdout
+        self.dataWritten = False
+
+    def write(self, data):
+        if data:
+            self.dataWritten = True
+        self._file.write(data)
+
+    def writelines(self, lines):
+        for line in lines:
+            self.write(line)
+
+    def __getattr__(self, name):
+        return getattr(self._file, name)
+
+def decode_pair(s, pos=0):
+    """
+    Decodes a name/value pair.
+
+    The number of bytes decoded as well as the name/value pair
+    are returned.
+    """
+    nameLength = ord(s[pos])
+    if nameLength & 128:
+        nameLength = struct.unpack('!L', s[pos:pos+4])[0] & 0x7fffffff
+        pos += 4
+    else:
+        pos += 1
+
+    valueLength = ord(s[pos])
+    if valueLength & 128:
+        valueLength = struct.unpack('!L', s[pos:pos+4])[0] & 0x7fffffff
+        pos += 4
+    else:
+        pos += 1
+
+    name = s[pos:pos+nameLength]
+    pos += nameLength
+    value = s[pos:pos+valueLength]
+    pos += valueLength
+
+    return (pos, (name, value))
+
+def encode_pair(name, value):
+    """
+    Encodes a name/value pair.
+
+    The encoded string is returned.
+    """
+    nameLength = len(name)
+    if nameLength < 128:
+        s = chr(nameLength)
+    else:
+        s = struct.pack('!L', nameLength | 0x80000000L)
+
+    valueLength = len(value)
+    if valueLength < 128:
+        s += chr(valueLength)
+    else:
+        s += struct.pack('!L', valueLength | 0x80000000L)
+
+    return s + name + value
+    
+class Record(object):
+    """
+    A FastCGI Record.
+
+    Used for encoding/decoding records.
+    """
+    def __init__(self, type=FCGI_UNKNOWN_TYPE, requestId=FCGI_NULL_REQUEST_ID):
+        self.version = FCGI_VERSION_1
+        self.type = type
+        self.requestId = requestId
+        self.contentLength = 0
+        self.paddingLength = 0
+        self.contentData = ''
+
+    def _recvall(sock, length):
+        """
+        Attempts to receive length bytes from a socket, blocking if necessary.
+        (Socket may be blocking or non-blocking.)
+        """
+        dataList = []
+        recvLen = 0
+        while length:
+            try:
+                data = sock.recv(length)
+            except socket.error, e:
+                if e[0] == errno.EAGAIN:
+                    select.select([sock], [], [])
+                    continue
+                else:
+                    raise
+            if not data: # EOF
+                break
+            dataList.append(data)
+            dataLen = len(data)
+            recvLen += dataLen
+            length -= dataLen
+        return ''.join(dataList), recvLen
+    _recvall = staticmethod(_recvall)
+
+    def read(self, sock):
+        """Read and decode a Record from a socket."""
+        try:
+            header, length = self._recvall(sock, FCGI_HEADER_LEN)
+        except:
+            raise EOFError
+
+        if length < FCGI_HEADER_LEN:
+            raise EOFError
+        
+        self.version, self.type, self.requestId, self.contentLength, \
+                      self.paddingLength = struct.unpack(FCGI_Header, header)
+
+        if __debug__: _debug(9, 'read: fd = %d, type = %d, requestId = %d, '
+                             'contentLength = %d' %
+                             (sock.fileno(), self.type, self.requestId,
+                              self.contentLength))
+        
+        if self.contentLength:
+            try:
+                self.contentData, length = self._recvall(sock,
+                                                         self.contentLength)
+            except:
+                raise EOFError
+
+            if length < self.contentLength:
+                raise EOFError
+
+        if self.paddingLength:
+            try:
+                self._recvall(sock, self.paddingLength)
+            except:
+                raise EOFError
+
+    def _sendall(sock, data):
+        """
+        Writes data to a socket and does not return until all the data is sent.
+        """
+        length = len(data)
+        while length:
+            try:
+                sent = sock.send(data)
+            except socket.error, e:
+                if e[0] == errno.EPIPE:
+                    return # Don't bother raising an exception. Just ignore.
+                elif e[0] == errno.EAGAIN:
+                    select.select([], [sock], [])
+                    continue
+                else:
+                    raise
+            data = data[sent:]
+            length -= sent
+    _sendall = staticmethod(_sendall)
+
+    def write(self, sock):
+        """Encode and write a Record to a socket."""
+        self.paddingLength = -self.contentLength & 7
+
+        if __debug__: _debug(9, 'write: fd = %d, type = %d, requestId = %d, '
+                             'contentLength = %d' %
+                             (sock.fileno(), self.type, self.requestId,
+                              self.contentLength))
+
+        header = struct.pack(FCGI_Header, self.version, self.type,
+                             self.requestId, self.contentLength,
+                             self.paddingLength)
+        self._sendall(sock, header)
+        if self.contentLength:
+            self._sendall(sock, self.contentData)
+        if self.paddingLength:
+            self._sendall(sock, '\x00'*self.paddingLength)
+            
+class Request(object):
+    """
+    Represents a single FastCGI request.
+
+    These objects are passed to your handler and is the main interface
+    between your handler and the fcgi module. The methods should not
+    be called by your handler. However, server, params, stdin, stdout,
+    stderr, and data are free for your handler's use.
+    """
+    def __init__(self, conn, inputStreamClass):
+        self._conn = conn
+
+        self.server = conn.server
+        self.params = {}
+        self.stdin = inputStreamClass(conn)
+        self.stdout = OutputStream(conn, self, FCGI_STDOUT)
+        self.stderr = OutputStream(conn, self, FCGI_STDERR, buffered=True)
+        self.data = inputStreamClass(conn)
+
+    def run(self):
+        """Runs the handler, flushes the streams, and ends the request."""
+        try:
+            protocolStatus, appStatus = self.server.handler(self)
+        except:
+            traceback.print_exc(file=self.stderr)
+            self.stderr.flush()
+            if not self.stdout.dataWritten:
+                self.server.error(self)
+
+            protocolStatus, appStatus = FCGI_REQUEST_COMPLETE, 0
+
+        if __debug__: _debug(1, 'protocolStatus = %d, appStatus = %d' %
+                             (protocolStatus, appStatus))
+
+        self._flush()
+        self._end(appStatus, protocolStatus)
+
+    def _end(self, appStatus=0L, protocolStatus=FCGI_REQUEST_COMPLETE):
+        self._conn.end_request(self, appStatus, protocolStatus)
+        
+    def _flush(self):
+        self.stdout.close()
+        self.stderr.close()
+
+class CGIRequest(Request):
+    """A normal CGI request disguised as a FastCGI request."""
+    def __init__(self, server):
+        # These are normally filled in by Connection.
+        self.requestId = 1
+        self.role = FCGI_RESPONDER
+        self.flags = 0
+        self.aborted = False
+        
+        self.server = server
+        self.params = dict(os.environ)
+        self.stdin = sys.stdin
+        self.stdout = StdoutWrapper(sys.stdout) # Oh, the humanity!
+        self.stderr = sys.stderr
+        self.data = StringIO.StringIO()
+        
+    def _end(self, appStatus=0L, protocolStatus=FCGI_REQUEST_COMPLETE):
+        sys.exit(appStatus)
+
+    def _flush(self):
+        # Not buffered, do nothing.
+        pass
+
+class Connection(object):
+    """
+    A Connection with the web server.
+
+    Each Connection is associated with a single socket (which is
+    connected to the web server) and is responsible for handling all
+    the FastCGI message processing for that socket.
+    """
+    _multiplexed = False
+    _inputStreamClass = InputStream
+
+    def __init__(self, sock, addr, server):
+        self._sock = sock
+        self._addr = addr
+        self.server = server
+
+        # Active Requests for this Connection, mapped by request ID.
+        self._requests = {}
+
+    def _cleanupSocket(self):
+        """Close the Connection's socket."""
+        try:
+            self._sock.shutdown(socket.SHUT_WR)
+        except:
+            return
+        try:
+            while True:
+                r, w, e = select.select([self._sock], [], [])
+                if not r or not self._sock.recv(1024):
+                    break
+        except:
+            pass
+        self._sock.close()
+        
+    def run(self):
+        """Begin processing data from the socket."""
+        self._keepGoing = True
+        while self._keepGoing:
+            try:
+                self.process_input()
+            except EOFError:
+                break
+            except (select.error, socket.error), e:
+                if e[0] == errno.EBADF: # Socket was closed by Request.
+                    break
+                raise
+
+        self._cleanupSocket()
+
+    def process_input(self):
+        """Attempt to read a single Record from the socket and process it."""
+        # Currently, any children Request threads notify this Connection
+        # that it is no longer needed by closing the Connection's socket.
+        # We need to put a timeout on select, otherwise we might get
+        # stuck in it indefinitely... (I don't like this solution.)
+        while self._keepGoing:
+            try:
+                r, w, e = select.select([self._sock], [], [], 1.0)
+            except ValueError:
+                # Sigh. ValueError gets thrown sometimes when passing select
+                # a closed socket.
+                raise EOFError
+            if r: break
+        if not self._keepGoing:
+            return
+        rec = Record()
+        rec.read(self._sock)
+
+        if rec.type == FCGI_GET_VALUES:
+            self._do_get_values(rec)
+        elif rec.type == FCGI_BEGIN_REQUEST:
+            self._do_begin_request(rec)
+        elif rec.type == FCGI_ABORT_REQUEST:
+            self._do_abort_request(rec)
+        elif rec.type == FCGI_PARAMS:
+            self._do_params(rec)
+        elif rec.type == FCGI_STDIN:
+            self._do_stdin(rec)
+        elif rec.type == FCGI_DATA:
+            self._do_data(rec)
+        elif rec.requestId == FCGI_NULL_REQUEST_ID:
+            self._do_unknown_type(rec)
+        else:
+            # Need to complain about this.
+            pass
+
+    def writeRecord(self, rec):
+        """
+        Write a Record to the socket.
+        """
+        rec.write(self._sock)
+
+    def end_request(self, req, appStatus=0L,
+                    protocolStatus=FCGI_REQUEST_COMPLETE, remove=True):
+        """
+        End a Request.
+
+        Called by Request objects. An FCGI_END_REQUEST Record is
+        sent to the web server. If the web server no longer requires
+        the connection, the socket is closed, thereby ending this
+        Connection (run() returns).
+        """
+        rec = Record(FCGI_END_REQUEST, req.requestId)
+        rec.contentData = struct.pack(FCGI_EndRequestBody, appStatus,
+                                      protocolStatus)
+        rec.contentLength = FCGI_EndRequestBody_LEN
+        self.writeRecord(rec)
+
+        if remove:
+            del self._requests[req.requestId]
+
+        if __debug__: _debug(2, 'end_request: flags = %d' % req.flags)
+
+        if not (req.flags & FCGI_KEEP_CONN) and not self._requests:
+            self._cleanupSocket()
+            self._keepGoing = False
+
+    def _do_get_values(self, inrec):
+        """Handle an FCGI_GET_VALUES request from the web server."""
+        outrec = Record(FCGI_GET_VALUES_RESULT)
+
+        pos = 0
+        while pos < inrec.contentLength:
+            pos, (name, value) = decode_pair(inrec.contentData, pos)
+            cap = self.server.capability.get(name)
+            if cap is not None:
+                outrec.contentData += encode_pair(name, str(cap))
+
+        outrec.contentLength = len(outrec.contentData)
+        self.writeRecord(rec)
+
+    def _do_begin_request(self, inrec):
+        """Handle an FCGI_BEGIN_REQUEST from the web server."""
+        role, flags = struct.unpack(FCGI_BeginRequestBody, inrec.contentData)
+
+        req = self.server.request_class(self, self._inputStreamClass)
+        req.requestId, req.role, req.flags = inrec.requestId, role, flags
+        req.aborted = False
+
+        if not self._multiplexed and self._requests:
+            # Can't multiplex requests.
+            self.end_request(req, 0L, FCGI_CANT_MPX_CONN, remove=False)
+        else:
+            self._requests[inrec.requestId] = req
+
+    def _do_abort_request(self, inrec):
+        """
+        Handle an FCGI_ABORT_REQUEST from the web server.
+
+        We just mark a flag in the associated Request.
+        """
+        req = self._requests.get(inrec.requestId)
+        if req is not None:
+            req.aborted = True
+
+    def _start_request(self, req):
+        """Run the request."""
+        # Not multiplexed, so run it inline.
+        req.run()
+
+    def _do_params(self, inrec):
+        """
+        Handle an FCGI_PARAMS Record.
+
+        If the last FCGI_PARAMS Record is received, start the request.
+        """
+        req = self._requests.get(inrec.requestId)
+        if req is not None:
+            if inrec.contentLength:
+                pos = 0
+                while pos < inrec.contentLength:
+                    pos, (name, value) = decode_pair(inrec.contentData, pos)
+                    req.params[name] = value
+            else:
+                self._start_request(req)
+
+    def _do_stdin(self, inrec):
+        """Handle the FCGI_STDIN stream."""
+        req = self._requests.get(inrec.requestId)
+        if req is not None:
+            req.stdin.add_data(inrec.contentData)
+
+    def _do_data(self, inrec):
+        """Handle the FCGI_DATA stream."""
+        req = self._requests.get(inrec.requestId)
+        if req is not None:
+            req.data.add_data(inrec.contentData)
+
+    def _do_unknown_type(self, inrec):
+        """Handle an unknown request type. Respond accordingly."""
+        outrec = Record(FCGI_UNKNOWN_TYPE)
+        outrec.contentData = struct.pack(FCGI_UnknownTypeBody, inrec.type)
+        outrec.contentLength = FCGI_UnknownTypeBody_LEN
+        self.writeRecord(rec)
+        
+class MultiplexedConnection(Connection):
+    """
+    A version of Connection capable of handling multiple requests
+    simultaneously.
+    """
+    _multiplexed = True
+    _inputStreamClass = MultiplexedInputStream
+
+    def __init__(self, sock, addr, server):
+        super(MultiplexedConnection, self).__init__(sock, addr, server)
+
+        # Used to arbitrate access to self._requests.
+        lock = threading.RLock()
+
+        # Notification is posted everytime a request completes, allowing us
+        # to quit cleanly.
+        self._lock = threading.Condition(lock)
+
+    def _cleanupSocket(self):
+        # Wait for any outstanding requests before closing the socket.
+        self._lock.acquire()
+        while self._requests:
+            self._lock.wait()
+        self._lock.release()
+
+        super(MultiplexedConnection, self)._cleanupSocket()
+        
+    def writeRecord(self, rec):
+        # Must use locking to prevent intermingling of Records from different
+        # threads.
+        self._lock.acquire()
+        try:
+            # Probably faster than calling super. ;)
+            rec.write(self._sock)
+        finally:
+            self._lock.release()
+
+    def end_request(self, req, appStatus=0L,
+                    protocolStatus=FCGI_REQUEST_COMPLETE, remove=True):
+        self._lock.acquire()
+        try:
+            super(MultiplexedConnection, self).end_request(req, appStatus,
+                                                           protocolStatus,
+                                                           remove)
+            self._lock.notify()
+        finally:
+            self._lock.release()
+
+    def _do_begin_request(self, inrec):
+        self._lock.acquire()
+        try:
+            super(MultiplexedConnection, self)._do_begin_request(inrec)
+        finally:
+            self._lock.release()
+
+    def _do_abort_request(self, inrec):
+        self._lock.acquire()
+        try:
+            super(MultiplexedConnection, self)._do_abort_request(inrec)
+        finally:
+            self._lock.release()
+
+    def _start_request(self, req):
+        thread.start_new_thread(req.run, ())
+
+    def _do_params(self, inrec):
+        self._lock.acquire()
+        try:
+            super(MultiplexedConnection, self)._do_params(inrec)
+        finally:
+            self._lock.release()
+
+    def _do_stdin(self, inrec):
+        self._lock.acquire()
+        try:
+            super(MultiplexedConnection, self)._do_stdin(inrec)
+        finally:
+            self._lock.release()
+
+    def _do_data(self, inrec):
+        self._lock.acquire()
+        try:
+            super(MultiplexedConnection, self)._do_data(inrec)
+        finally:
+            self._lock.release()
+        
+class Server(object):
+    """
+    The FastCGI server.
+
+    Waits for connections from the web server, processing each
+    request.
+
+    If run in a normal CGI context, it will instead instantiate a
+    CGIRequest and run the handler through there.
+    """
+    request_class = Request
+    cgirequest_class = CGIRequest
+
+    # Limits the size of the InputStream's string buffer to this size + the
+    # server's maximum Record size. Since the InputStream is not seekable,
+    # we throw away already-read data once this certain amount has been read.
+    inputStreamShrinkThreshold = 102400 - 8192
+
+    def __init__(self, handler=None, maxwrite=8192, bindAddress=None,
+                 multiplexed=False):
+        """
+        handler, if present, must reference a function or method that
+        takes one argument: a Request object. If handler is not
+        specified at creation time, Server *must* be subclassed.
+        (The handler method below is abstract.)
+
+        maxwrite is the maximum number of bytes (per Record) to write
+        to the server. I've noticed mod_fastcgi has a relatively small
+        receive buffer (8K or so).
+
+        bindAddress, if present, must either be a string or a 2-tuple. If
+        present, run() will open its own listening socket. You would use
+        this if you wanted to run your application as an 'external' FastCGI
+        app. (i.e. the webserver would no longer be responsible for starting
+        your app) If a string, it will be interpreted as a filename and a UNIX
+        socket will be opened. If a tuple, the first element, a string,
+        is the interface name/IP to bind to, and the second element (an int)
+        is the port number.
+
+        Set multiplexed to True if you want to handle multiple requests
+        per connection. Some FastCGI backends (namely mod_fastcgi) don't
+        multiplex requests at all, so by default this is off (which saves
+        on thread creation/locking overhead). If threads aren't available,
+        this keyword is ignored; it's not possible to multiplex requests
+        at all.
+        """
+        if handler is not None:
+            self.handler = handler
+        self.maxwrite = maxwrite
+        if thread_available:
+            try:
+                import resource
+                # Attempt to glean the maximum number of connections
+                # from the OS.
+                maxConns = resource.getrlimit(resource.RLIMIT_NOFILE)[0]
+            except ImportError:
+                maxConns = 100 # Just some made up number.
+            maxReqs = maxConns
+            if multiplexed:
+                self._connectionClass = MultiplexedConnection
+                maxReqs *= 5 # Another made up number.
+            else:
+                self._connectionClass = Connection
+            self.capability = {
+                FCGI_MAX_CONNS: maxConns,
+                FCGI_MAX_REQS: maxReqs,
+                FCGI_MPXS_CONNS: multiplexed and 1 or 0
+                }
+        else:
+            self._connectionClass = Connection
+            self.capability = {
+                # If threads aren't available, these are pretty much correct.
+                FCGI_MAX_CONNS: 1,
+                FCGI_MAX_REQS: 1,
+                FCGI_MPXS_CONNS: 0
+                }
+        self._bindAddress = bindAddress
+
+    def _setupSocket(self):
+        if self._bindAddress is None: # Run as a normal FastCGI?
+            isFCGI = True
+
+            sock = socket.fromfd(FCGI_LISTENSOCK_FILENO, socket.AF_INET,
+                                 socket.SOCK_STREAM)
+            try:
+                sock.getpeername()
+            except socket.error, e:
+                if e[0] == errno.ENOTSOCK:
+                    # Not a socket, assume CGI context.
+                    isFCGI = False
+                elif e[0] != errno.ENOTCONN:
+                    raise
+
+            # FastCGI/CGI discrimination is broken on Mac OS X.
+            # Set the environment variable FCGI_FORCE_CGI to "Y" or "y"
+            # if you want to run your app as a simple CGI. (You can do
+            # this with Apache's mod_env [not loaded by default in OS X
+            # client, ha ha] and the SetEnv directive.)
+            if not isFCGI or \
+               os.environ.get('FCGI_FORCE_CGI', 'N').upper().startswith('Y'):
+                req = self.cgirequest_class(self)
+                req.run()
+                sys.exit(0)
+        else:
+            # Run as a server
+            if type(self._bindAddress) is str:
+                # Unix socket
+                sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+                try:
+                    os.unlink(self._bindAddress)
+                except OSError:
+                    pass
+            else:
+                # INET socket
+                assert type(self._bindAddress) is tuple
+                assert len(self._bindAddress) == 2
+                sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+                sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+
+            sock.bind(self._bindAddress)
+            sock.listen(socket.SOMAXCONN)
+
+        return sock
+
+    def _cleanupSocket(self, sock):
+        """Closes the main socket."""
+        sock.close()
+
+    def _installSignalHandlers(self):
+        self._oldSIGs = [(x,signal.getsignal(x)) for x in
+                         (signal.SIGHUP, signal.SIGINT, signal.SIGTERM)]
+        signal.signal(signal.SIGHUP, self._hupHandler)
+        signal.signal(signal.SIGINT, self._intHandler)
+        signal.signal(signal.SIGTERM, self._intHandler)
+
+    def _restoreSignalHandlers(self):
+        for signum,handler in self._oldSIGs:
+            signal.signal(signum, handler)
+        
+    def _hupHandler(self, signum, frame):
+        self._hupReceived = True
+        self._keepGoing = False
+
+    def _intHandler(self, signum, frame):
+        self._keepGoing = False
+
+    def run(self, timeout=1.0):
+        """
+        The main loop. Exits on SIGHUP, SIGINT, SIGTERM. Returns True if
+        SIGHUP was received, False otherwise.
+        """
+        web_server_addrs = os.environ.get('FCGI_WEB_SERVER_ADDRS')
+        if web_server_addrs is not None:
+            web_server_addrs = map(lambda x: x.strip(),
+                                   web_server_addrs.split(','))
+
+        sock = self._setupSocket()
+
+        self._keepGoing = True
+        self._hupReceived = False
+
+        # Install signal handlers.
+        self._installSignalHandlers()
+
+        while self._keepGoing:
+            try:
+                r, w, e = select.select([sock], [], [], timeout)
+            except select.error, e:
+                if e[0] == errno.EINTR:
+                    continue
+                raise
+
+            if r:
+                try:
+                    clientSock, addr = sock.accept()
+                except socket.error, e:
+                    if e[0] in (errno.EINTR, errno.EAGAIN):
+                        continue
+                    raise
+
+                if web_server_addrs and \
+                       (len(addr) != 2 or addr[0] not in web_server_addrs):
+                    clientSock.close()
+                    continue
+
+                # Instantiate a new Connection and begin processing FastCGI
+                # messages (either in a new thread or this thread).
+                conn = self._connectionClass(clientSock, addr, self)
+                thread.start_new_thread(conn.run, ())
+
+            self._mainloopPeriodic()
+
+        # Restore signal handlers.
+        self._restoreSignalHandlers()
+
+        self._cleanupSocket(sock)
+
+        return self._hupReceived
+
+    def _mainloopPeriodic(self):
+        """
+        Called with just about each iteration of the main loop. Meant to
+        be overridden.
+        """
+        pass
+
+    def _exit(self, reload=False):
+        """
+        Protected convenience method for subclasses to force an exit. Not
+        really thread-safe, which is why it isn't public.
+        """
+        if self._keepGoing:
+            self._keepGoing = False
+            self._hupReceived = reload
+
+    def handler(self, req):
+        """
+        Default handler, which just raises an exception. Unless a handler
+        is passed at initialization time, this must be implemented by
+        a subclass.
+        """
+        raise NotImplementedError, self.__class__.__name__ + '.handler'
+
+    def error(self, req):
+        """
+        Called by Request if an exception occurs within the handler. May and
+        should be overridden.
+        """
+        import cgitb
+        req.stdout.write('Content-Type: text/html\r\n\r\n' +
+                         cgitb.html(sys.exc_info()))
+
+class WSGIServer(Server):
+    """
+    FastCGI server that supports the Web Server Gateway Interface. See
+    <http://www.python.org/peps/pep-0333.html>.
+    """
+    def __init__(self, application, environ=None, multithreaded=True, **kw):
+        """
+        environ, if present, must be a dictionary-like object. Its
+        contents will be copied into application's environ. Useful
+        for passing application-specific variables.
+
+        Set multithreaded to False if your application is not MT-safe.
+        """
+        if kw.has_key('handler'):
+            del kw['handler'] # Doesn't make sense to let this through
+        super(WSGIServer, self).__init__(**kw)
+
+        if environ is None:
+            environ = {}
+
+        self.application = application
+        self.environ = environ
+        self.multithreaded = multithreaded
+
+        # Used to force single-threadedness
+        self._app_lock = thread.allocate_lock()
+
+    def handler(self, req):
+        """Special handler for WSGI."""
+        if req.role != FCGI_RESPONDER:
+            return FCGI_UNKNOWN_ROLE, 0
+
+        # Mostly taken from example CGI gateway.
+        environ = req.params
+        environ.update(self.environ)
+
+        environ['wsgi.version'] = (1,0)
+        environ['wsgi.input'] = req.stdin
+        if self._bindAddress is None:
+            stderr = req.stderr
+        else:
+            stderr = TeeOutputStream((sys.stderr, req.stderr))
+        environ['wsgi.errors'] = stderr
+        environ['wsgi.multithread'] = not isinstance(req, CGIRequest) and \
+                                      thread_available and self.multithreaded
+        # Rationale for the following: If started by the web server
+        # (self._bindAddress is None) in either FastCGI or CGI mode, the
+        # possibility of being spawned multiple times simultaneously is quite
+        # real. And, if started as an external server, multiple copies may be
+        # spawned for load-balancing/redundancy. (Though I don't think
+        # mod_fastcgi supports this?)
+        environ['wsgi.multiprocess'] = True
+        environ['wsgi.run_once'] = isinstance(req, CGIRequest)
+
+        if environ.get('HTTPS', 'off') in ('on', '1'):
+            environ['wsgi.url_scheme'] = 'https'
+        else:
+            environ['wsgi.url_scheme'] = 'http'
+
+        self._sanitizeEnv(environ)
+
+        headers_set = []
+        headers_sent = []
+        result = None
+
+        def write(data):
+            assert type(data) is str, 'write() argument must be string'
+            assert headers_set, 'write() before start_response()'
+
+            if not headers_sent:
+                status, responseHeaders = headers_sent[:] = headers_set
+                found = False
+                for header,value in responseHeaders:
+                    if header.lower() == 'content-length':
+                        found = True
+                        break
+                if not found and result is not None:
+                    try:
+                        if len(result) == 1:
+                            responseHeaders.append(('Content-Length',
+                                                    str(len(data))))
+                    except:
+                        pass
+                s = 'Status: %s\r\n' % status
+                for header in responseHeaders:
+                    s += '%s: %s\r\n' % header
+                s += '\r\n'
+                req.stdout.write(s)
+
+            req.stdout.write(data)
+            req.stdout.flush()
+
+        def start_response(status, response_headers, exc_info=None):
+            if exc_info:
+                try:
+                    if headers_sent:
+                        # Re-raise if too late
+                        raise exc_info[0], exc_info[1], exc_info[2]
+                finally:
+                    exc_info = None # avoid dangling circular ref
+            else:
+                assert not headers_set, 'Headers already set!'
+
+            assert type(status) is str, 'Status must be a string'
+            assert len(status) >= 4, 'Status must be at least 4 characters'
+            assert int(status[:3]), 'Status must begin with 3-digit code'
+            assert status[3] == ' ', 'Status must have a space after code'
+            assert type(response_headers) is list, 'Headers must be a list'
+            if __debug__:
+                for name,val in response_headers:
+                    assert type(name) is str, 'Header names must be strings'
+                    assert type(val) is str, 'Header values must be strings'
+
+            headers_set[:] = [status, response_headers]
+            return write
+
+        if not self.multithreaded:
+            self._app_lock.acquire()
+        try:
+            result = self.application(environ, start_response)
+            try:
+                for data in result:
+                    if data:
+                        write(data)
+                if not headers_sent:
+                    write('') # in case body was empty
+            finally:
+                if hasattr(result, 'close'):
+                    result.close()
+        finally:
+            if not self.multithreaded:
+                self._app_lock.release()
+
+        return FCGI_REQUEST_COMPLETE, 0
+
+    def _sanitizeEnv(self, environ):
+        """Ensure certain values are present, if required by WSGI."""
+        if not environ.has_key('SCRIPT_NAME'):
+            environ['SCRIPT_NAME'] = ''
+        if not environ.has_key('PATH_INFO'):
+            environ['PATH_INFO'] = ''
+
+        # If any of these are missing, it probably signifies a broken
+        # server...
+        for name,default in [('REQUEST_METHOD', 'GET'),
+                             ('SERVER_NAME', 'localhost'),
+                             ('SERVER_PORT', '80'),
+                             ('SERVER_PROTOCOL', 'HTTP/1.0')]:
+            if not environ.has_key(name):
+                environ['wsgi.errors'].write('%s: missing FastCGI param %s '
+                                             'required by WSGI!\n' %
+                                             (self.__class__.__name__, name))
+                environ[name] = default
+            
+if __name__ == '__main__':
+    def test_app(environ, start_response):
+        """Probably not the most efficient example."""
+        import cgi
+        start_response('200 OK', [('Content-Type', 'text/html')])
+        yield '<html><head><title>Hello World!</title></head>\n' \
+              '<body>\n' \
+              '<p>Hello World!</p>\n' \
+              '<table border="1">'
+        names = environ.keys()
+        names.sort()
+        for name in names:
+            yield '<tr><td>%s</td><td>%s</td></tr>\n' % (
+                name, cgi.escape(`environ[name]`))
+
+        form = cgi.FieldStorage(fp=environ['wsgi.input'], environ=environ,
+                                keep_blank_values=1)
+        if form.list:
+            yield '<tr><th colspan="2">Form data</th></tr>'
+
+        for field in form.list:
+            yield '<tr><td>%s</td><td>%s</td></tr>\n' % (
+                field.name, field.value)
+
+        yield '</table>\n' \
+              '</body></html>\n'
+
+    WSGIServer(test_app).run()