plexpy/lib/cheroot/connections.py
2019-11-23 19:03:04 -08:00

280 lines
9.6 KiB
Python

"""Utilities to manage open connections."""
from __future__ import absolute_import, division, print_function
__metaclass__ = type
import io
import os
import select
import socket
import time
from . import errors
from .makefile import MakeFile
import six
try:
import fcntl
except ImportError:
try:
from ctypes import windll, WinError
import ctypes.wintypes
_SetHandleInformation = windll.kernel32.SetHandleInformation
_SetHandleInformation.argtypes = [
ctypes.wintypes.HANDLE,
ctypes.wintypes.DWORD,
ctypes.wintypes.DWORD,
]
_SetHandleInformation.restype = ctypes.wintypes.BOOL
except ImportError:
def prevent_socket_inheritance(sock):
"""Stub inheritance prevention.
Dummy function, since neither fcntl nor ctypes are available.
"""
pass
else:
def prevent_socket_inheritance(sock):
"""Mark the given socket fd as non-inheritable (Windows)."""
if not _SetHandleInformation(sock.fileno(), 1, 0):
raise WinError()
else:
def prevent_socket_inheritance(sock):
"""Mark the given socket fd as non-inheritable (POSIX)."""
fd = sock.fileno()
old_flags = fcntl.fcntl(fd, fcntl.F_GETFD)
fcntl.fcntl(fd, fcntl.F_SETFD, old_flags | fcntl.FD_CLOEXEC)
class ConnectionManager:
"""Class which manages HTTPConnection objects.
This is for connections which are being kept-alive for follow-up requests.
"""
def __init__(self, server):
"""Initialize ConnectionManager object.
Args:
server (cheroot.server.HTTPServer): web server object
that uses this ConnectionManager instance.
"""
self.server = server
self.connections = []
def put(self, conn):
"""Put idle connection into the ConnectionManager to be managed.
Args:
conn (cheroot.server.HTTPConnection): HTTP connection
to be managed.
"""
conn.last_used = time.time()
conn.ready_with_data = conn.rfile.has_data()
self.connections.append(conn)
def expire(self):
"""Expire least recently used connections.
This happens if there are either too many open connections, or if the
connections have been timed out.
This should be called periodically.
"""
if not self.connections:
return
# Look at the first connection - if it can be closed, then do
# that, and wait for get_conn to return it.
conn = self.connections[0]
if conn.closeable:
return
# Too many connections?
ka_limit = self.server.keep_alive_conn_limit
if ka_limit is not None and len(self.connections) > ka_limit:
conn.closeable = True
return
# Connection too old?
if (conn.last_used + self.server.timeout) < time.time():
conn.closeable = True
return
def get_conn(self, server_socket):
"""Return a HTTPConnection object which is ready to be handled.
A connection returned by this method should be ready for a worker
to handle it. If there are no connections ready, None will be
returned.
Any connection returned by this method will need to be `put`
back if it should be examined again for another request.
Args:
server_socket (socket.socket): Socket to listen to for new
connections.
Returns:
cheroot.server.HTTPConnection instance, or None.
"""
# Grab file descriptors from sockets, but stop if we find a
# connection which is already marked as ready.
socket_dict = {}
for conn in self.connections:
if conn.closeable or conn.ready_with_data:
break
socket_dict[conn.socket.fileno()] = conn
else:
# No ready connection.
conn = None
# We have a connection ready for use.
if conn:
self.connections.remove(conn)
return conn
# Will require a select call.
ss_fileno = server_socket.fileno()
socket_dict[ss_fileno] = server_socket
try:
rlist, _, _ = select.select(list(socket_dict), [], [], 0.1)
# No available socket.
if not rlist:
return None
except OSError:
# Mark any connection which no longer appears valid.
for fno, conn in list(socket_dict.items()):
# If the server socket is invalid, we'll just ignore it and
# wait to be shutdown.
if fno == ss_fileno:
continue
try:
os.fstat(fno)
except OSError:
# Socket is invalid, close the connection, insert at
# the front.
self.connections.remove(conn)
self.connections.insert(0, conn)
conn.closeable = True
# Wait for the next tick to occur.
return None
try:
# See if we have a new connection coming in.
rlist.remove(ss_fileno)
except ValueError:
# No new connection, but reuse existing socket.
conn = socket_dict[rlist.pop()]
else:
conn = server_socket
# All remaining connections in rlist should be marked as ready.
for fno in rlist:
socket_dict[fno].ready_with_data = True
# New connection.
if conn is server_socket:
return self._from_server_socket(server_socket)
self.connections.remove(conn)
return conn
def _from_server_socket(self, server_socket):
try:
s, addr = server_socket.accept()
if self.server.stats['Enabled']:
self.server.stats['Accepts'] += 1
prevent_socket_inheritance(s)
if hasattr(s, 'settimeout'):
s.settimeout(self.server.timeout)
mf = MakeFile
ssl_env = {}
# if ssl cert and key are set, we try to be a secure HTTP server
if self.server.ssl_adapter is not None:
try:
s, ssl_env = self.server.ssl_adapter.wrap(s)
except errors.NoSSLError:
msg = (
'The client sent a plain HTTP request, but '
'this server only speaks HTTPS on this port.'
)
buf = [
'%s 400 Bad Request\r\n' % self.server.protocol,
'Content-Length: %s\r\n' % len(msg),
'Content-Type: text/plain\r\n\r\n',
msg,
]
sock_to_make = s if not six.PY2 else s._sock
wfile = mf(sock_to_make, 'wb', io.DEFAULT_BUFFER_SIZE)
try:
wfile.write(''.join(buf).encode('ISO-8859-1'))
except socket.error as ex:
if ex.args[0] not in errors.socket_errors_to_ignore:
raise
return
if not s:
return
mf = self.server.ssl_adapter.makefile
# Re-apply our timeout since we may have a new socket object
if hasattr(s, 'settimeout'):
s.settimeout(self.server.timeout)
conn = self.server.ConnectionClass(self.server, s, mf)
if not isinstance(
self.server.bind_addr,
(six.text_type, six.binary_type),
):
# optional values
# Until we do DNS lookups, omit REMOTE_HOST
if addr is None: # sometimes this can happen
# figure out if AF_INET or AF_INET6.
if len(s.getsockname()) == 2:
# AF_INET
addr = ('0.0.0.0', 0)
else:
# AF_INET6
addr = ('::', 0)
conn.remote_addr = addr[0]
conn.remote_port = addr[1]
conn.ssl_env = ssl_env
return conn
except socket.timeout:
# The only reason for the timeout in start() is so we can
# notice keyboard interrupts on Win32, which don't interrupt
# accept() by default
return
except socket.error as ex:
if self.server.stats['Enabled']:
self.server.stats['Socket Errors'] += 1
if ex.args[0] in errors.socket_error_eintr:
# I *think* this is right. EINTR should occur when a signal
# is received during the accept() call; all docs say retry
# the call, and I *think* I'm reading it right that Python
# will then go ahead and poll for and handle the signal
# elsewhere. See
# https://github.com/cherrypy/cherrypy/issues/707.
return
if ex.args[0] in errors.socket_errors_nonblocking:
# Just try again. See
# https://github.com/cherrypy/cherrypy/issues/479.
return
if ex.args[0] in errors.socket_errors_to_ignore:
# Our socket was closed.
# See https://github.com/cherrypy/cherrypy/issues/686.
return
raise
def close(self):
"""Close all monitored connections."""
for conn in self.connections[:]:
conn.close()
self.connections = []