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__all__ = []
import asyncore
import socket
import sys
try:
import cStringIO as StringIO
except ImportError:
import StringIO
class SCGIConnection(asyncore.dispatcher):
"""SCGI connection class used by L{SCGIServer}."""
# connection states
NEW = 0*4 | 1 # connection established, waiting for request
HEADER = 1*4 | 1 # the request length was received, waiting for the rest
BODY = 2*4 | 1 # the request header was received, waiting for the body
REQ = 3*4 | 2 # request received, sending response
def __init__(self, server, connection, addr, maxrequestsize=65536,
maxpostsize=8<<20, blocksize=4096):
asyncore.dispatcher.__init__(self, connection)
self.server = server # WSGISCGIServer instance
self.addr = addr # scgi client address
self.maxrequestsize = maxrequestsize
self.maxpostsize = maxpostsize
self.blocksize = blocksize
self.state = SCGIConnection.NEW # internal state
self.environ = {} # environment passed to wsgi app
self.reqlen = -1 # request length used in two different meanings
self.inbuff = "" # input buffer
self.outbuff = "" # output buffer
self.wsgihandler = None # wsgi application iterator
self.outheaders = () # headers to be sent
# () -> unset, (..,..) -> set, True -> sent
self.body = StringIO.StringIO() # request body
def _wsgi_headers(self):
return {"wsgi.version": (1, 0),
"wsgi.input": self.body,
"wsgi.errors": self.server.error,
"wsgi.url_scheme": "http",
"wsgi.multithread": False,
"wsgi.multiprocess": False,
"wsgi.run_once": False}
def _try_send_headers(self):
if self.outheaders != True:
assert not self.outbuff
status, headers = self.outheaders
headdata = "".join(map("%s: %s\r\n".__mod__, headers))
self.outbuff = "Status: %s\r\n%s\r\n" % (status, headdata)
self.outheaders = True
def _wsgi_write(self, data):
assert self.state >= SCGIConnection.REQ
assert isinstance(data, str)
if data:
self._try_send_headers()
self.outbuff += data
def readable(self):
"""C{asyncore} interface"""
return self.state & 1 == 1
def writable(self):
"""C{asyncore} interface"""
return self.state & 2 == 2
def handle_read(self):
"""C{asyncore} interface"""
data = self.recv(self.blocksize)
self.inbuff += data
if self.state == SCGIConnection.NEW:
if ':' in self.inbuff:
reqlen, self.inbuff = self.inbuff.split(':', 1)
if not reqlen.isdigit():
self.close()
return # invalid request format
reqlen = long(reqlen)
if reqlen > self.maxrequestsize:
self.close()
return # request too long
self.reqlen = reqlen
self.state = SCGIConnection.HEADER
elif len(self.inbuff) > self.maxrequestsize:
self.close()
return # request too long
if self.state == SCGIConnection.HEADER:
buff = self.inbuff[:self.reqlen]
remainder = self.inbuff[self.reqlen:]
while buff.count('\0') >= 2:
key, value, buff = buff.split('\0', 2)
self.environ[key] = value
self.reqlen -= len(key) + len(value) + 2
self.inbuff = buff + remainder
if self.reqlen == 0:
if self.inbuff.startswith(','):
self.inbuff = self.inbuff[1:]
if not self.environ.get("CONTENT_LENGTH", "bad").isdigit():
self.close()
return
self.reqlen = long(self.environ["CONTENT_LENGTH"])
if self.reqlen > self.maxpostsize:
self.close()
return
self.state = SCGIConnection.BODY
else:
self.close()
return # protocol violation
if self.state == SCGIConnection.BODY:
if len(self.inbuff) >= self.reqlen:
self.body.write(self.inbuff[:self.reqlen])
self.body.seek(0)
self.inbuff = ""
self.reqlen = 0
self.environ.update(self._wsgi_headers())
if self.environ.get("HTTPS", "no").lower() in ('yes', 'y', '1'):
self.environ["wsgi.url_scheme"] = "https"
if "HTTP_CONTENT_TYPE" in self.environ:
self.environ["CONTENT_TYPE"] = \
self.environ.pop("HTTP_CONTENT_TYPE")
if "HTTP_CONTENT_LENGTH" in self.environ:
del self.environ["HTTP_CONTENT_LENGTH"] # TODO: better way?
self.wsgihandler = iter(self.server.wsgiapp(
self.environ, self.start_response))
self.state = SCGIConnection.REQ
else:
self.body.write(self.inbuff)
self.reqlen -= len(self.inbuff)
self.inbuff = ""
def start_response(self, status, headers, exc_info=None):
assert isinstance(status, str)
assert isinstance(headers, list)
if exc_info:
if self.outheaders == True:
try:
raise exc_info[0], exc_info[1], exc_info[2]
finally:
exc_info = None
assert self.outheaders != True # unsent
self.outheaders = (status, headers)
return self._wsgi_write
def handle_write(self):
"""C{asyncore} interface"""
assert self.state >= SCGIConnection.REQ
if len(self.outbuff) < self.blocksize:
self._try_send_headers()
for data in self.wsgihandler:
assert isinstance(data, str)
if data:
self.outbuff += data
if len(self.outbuff) >= self.blocksize:
break
if len(self.outbuff) == 0:
if hasattr(self.wsgihandler, "close"):
self.wsgihandler.close()
self.close()
return
try:
sentbytes = self.send(self.outbuff[:self.blocksize])
except socket.error:
if hasattr(self.wsgihandler, "close"):
self.wsgihandler.close()
self.close()
return
self.outbuff = self.outbuff[sentbytes:]
def handle_close(self):
"""C{asyncore} interface"""
self.close()
__all__.append("SCGIServer")
class SCGIServer(asyncore.dispatcher):
"""SCGI Server for WSGI applications. It does not use multiple processes or
multiple threads."""
def __init__(self, wsgiapp, port, interface="localhost", error=sys.stderr,
maxrequestsize=None, maxpostsize=None, blocksize=None):
"""
@param wsgiapp: is the wsgi application to be run.
@type port: int
@param port: is an int representing the TCP port number to be used.
@type interface: str
@param interface: is a string specifying the network interface to bind
which defaults to C{"localhost"} making the server inaccessible
over network.
@param error: is a file-like object being passed as C{wsgi.error} in the
environ parameter defaulting to stderr.
@type maxrequestsize: int
@param maxrequestsize: limit the size of request blocks in scgi
connections. Connections are dropped when this limit is hit.
@type maxpostsize: int
@param maxpostsize: limit the size of post bodies that may be processed
by this instance. Connections are dropped when this limit is
hit.
@type blocksize: int
@param blocksize: is amount of data to read or write from or to the
network at once
"""
asyncore.dispatcher.__init__(self)
self.wsgiapp = wsgiapp
self.error = error
self.conf = {}
if maxrequestsize is not None:
self.conf["maxrequestsize"] = maxrequestsize
if maxpostsize is not None:
self.conf["maxpostsize"] = maxpostsize
if blocksize is not None:
self.conf["blocksize"] = blocksize
self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
self.set_reuse_addr()
self.bind((interface, port))
self.listen(5)
def handle_accept(self):
"""asyncore interface"""
ret = self.accept()
if ret is not None:
conn, addr = ret
SCGIConnection(self, conn, addr, **self.conf)
def run(self):
"""Runs the server. It will not return and you can invoke
C{asyncore.loop()} instead achieving the same effect."""
asyncore.loop()
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