root / lib / http / __init__.py @ 99b5ef90
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# Copyright (C) 2007, 2008 Google Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA.
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"""HTTP module.
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"""
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import logging |
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import mimetools |
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import OpenSSL |
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import select |
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import socket |
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import errno |
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from cStringIO import StringIO |
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from ganeti import constants |
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from ganeti import serializer |
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from ganeti import utils |
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HTTP_CLIENT_THREADS = 10
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HTTP_GANETI_VERSION = "Ganeti %s" % constants.RELEASE_VERSION
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HTTP_OK = 200
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HTTP_NO_CONTENT = 204
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HTTP_NOT_MODIFIED = 304
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HTTP_0_9 = "HTTP/0.9"
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HTTP_1_0 = "HTTP/1.0"
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HTTP_1_1 = "HTTP/1.1"
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HTTP_GET = "GET"
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HTTP_HEAD = "HEAD"
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HTTP_POST = "POST"
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HTTP_PUT = "PUT"
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HTTP_DELETE = "DELETE"
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HTTP_ETAG = "ETag"
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HTTP_HOST = "Host"
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HTTP_SERVER = "Server"
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HTTP_DATE = "Date"
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HTTP_USER_AGENT = "User-Agent"
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HTTP_CONTENT_TYPE = "Content-Type"
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HTTP_CONTENT_LENGTH = "Content-Length"
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HTTP_CONNECTION = "Connection"
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HTTP_KEEP_ALIVE = "Keep-Alive"
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_SSL_UNEXPECTED_EOF = "Unexpected EOF"
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# Socket operations
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(SOCKOP_SEND, |
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SOCKOP_RECV, |
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SOCKOP_SHUTDOWN) = range(3) |
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class HttpError(Exception): |
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"""Internal exception for HTTP errors.
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This should only be used for internal error reporting.
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"""
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class _HttpClientError(Exception): |
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"""Internal exception for HTTP client errors.
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This should only be used for internal error reporting.
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"""
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class HttpSocketTimeout(Exception): |
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"""Internal exception for socket timeouts.
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This should only be used for internal error reporting.
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"""
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class HttpException(Exception): |
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code = None
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message = None
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def __init__(self, message=None): |
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Exception.__init__(self) |
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if message is not None: |
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self.message = message
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class HttpBadRequest(HttpException): |
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code = 400
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class HttpForbidden(HttpException): |
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code = 403
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class HttpNotFound(HttpException): |
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code = 404
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class HttpGone(HttpException): |
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code = 410
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class HttpLengthRequired(HttpException): |
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code = 411
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class HttpInternalError(HttpException): |
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code = 500
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class HttpNotImplemented(HttpException): |
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code = 501
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class HttpServiceUnavailable(HttpException): |
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code = 503
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class HttpVersionNotSupported(HttpException): |
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code = 505
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class HttpJsonConverter: |
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CONTENT_TYPE = "application/json"
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def Encode(self, data): |
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return serializer.DumpJson(data)
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def Decode(self, data): |
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return serializer.LoadJson(data)
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def WaitForSocketCondition(poller, sock, event, timeout): |
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"""Waits for a condition to occur on the socket.
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@type poller: select.Poller
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@param poller: Poller object as created by select.poll()
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@type sock: socket
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@param socket: Wait for events on this socket
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@type event: int
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@param event: ORed condition (see select module)
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@type timeout: float or None
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@param timeout: Timeout in seconds
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@rtype: int or None
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@return: None for timeout, otherwise occured conditions
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"""
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check = (event | select.POLLPRI | |
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select.POLLNVAL | select.POLLHUP | select.POLLERR) |
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if timeout is not None: |
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# Poller object expects milliseconds
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timeout *= 1000
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poller.register(sock, event) |
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try:
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while True: |
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# TODO: If the main thread receives a signal and we have no timeout, we
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# could wait forever. This should check a global "quit" flag or
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# something every so often.
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io_events = poller.poll(timeout) |
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if not io_events: |
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# Timeout
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return None |
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for (evfd, evcond) in io_events: |
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if evcond & check:
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return evcond
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finally:
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poller.unregister(sock) |
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def SocketOperation(poller, sock, op, arg1, timeout): |
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"""Wrapper around socket functions.
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This function abstracts error handling for socket operations, especially
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for the complicated interaction with OpenSSL.
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@type poller: select.Poller
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@param poller: Poller object as created by select.poll()
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@type sock: socket
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@param socket: Socket for the operation
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@type op: int
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@param op: Operation to execute (SOCKOP_* constants)
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@type arg1: any
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@param arg1: Parameter for function (if needed)
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@type timeout: None or float
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@param timeout: Timeout in seconds or None
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"""
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# TODO: event_poll/event_check/override
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if op == SOCKOP_SEND:
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event_poll = select.POLLOUT |
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event_check = select.POLLOUT |
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elif op == SOCKOP_RECV:
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event_poll = select.POLLIN |
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event_check = select.POLLIN | select.POLLPRI |
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elif op == SOCKOP_SHUTDOWN:
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event_poll = None
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event_check = None
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# The timeout is only used when OpenSSL requests polling for a condition.
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# It is not advisable to have no timeout for shutdown.
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assert timeout
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else:
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raise AssertionError("Invalid socket operation") |
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# No override by default
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event_override = 0
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while True: |
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# Poll only for certain operations and when asked for by an override
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if event_override or op in (SOCKOP_SEND, SOCKOP_RECV): |
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if event_override:
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wait_for_event = event_override |
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else:
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wait_for_event = event_poll |
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event = WaitForSocketCondition(poller, sock, wait_for_event, timeout) |
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if event is None: |
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raise HttpSocketTimeout()
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if (op == SOCKOP_RECV and |
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event & (select.POLLNVAL | select.POLLHUP | select.POLLERR)): |
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return "" |
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if not event & wait_for_event: |
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continue
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# Reset override
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event_override = 0
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try:
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try:
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if op == SOCKOP_SEND:
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return sock.send(arg1)
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elif op == SOCKOP_RECV:
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return sock.recv(arg1)
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elif op == SOCKOP_SHUTDOWN:
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if isinstance(sock, OpenSSL.SSL.ConnectionType): |
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# PyOpenSSL's shutdown() doesn't take arguments
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return sock.shutdown()
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else:
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return sock.shutdown(arg1)
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except OpenSSL.SSL.WantWriteError:
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# OpenSSL wants to write, poll for POLLOUT
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event_override = select.POLLOUT |
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continue
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except OpenSSL.SSL.WantReadError:
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# OpenSSL wants to read, poll for POLLIN
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event_override = select.POLLIN | select.POLLPRI |
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continue
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except OpenSSL.SSL.WantX509LookupError:
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continue
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except OpenSSL.SSL.SysCallError, err:
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if op == SOCKOP_SEND:
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# arg1 is the data when writing
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if err.args and err.args[0] == -1 and arg1 == "": |
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# errors when writing empty strings are expected
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# and can be ignored
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return 0 |
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elif op == SOCKOP_RECV:
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if err.args == (-1, _SSL_UNEXPECTED_EOF): |
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return "" |
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raise socket.error(err.args)
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except OpenSSL.SSL.Error, err:
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raise socket.error(err.args)
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except socket.error, err:
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if err.args and err.args[0] == errno.EAGAIN: |
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# Ignore EAGAIN
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continue
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raise
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def ShutdownConnection(poller, sock, close_timeout, write_timeout, msgreader, |
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force): |
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"""Closes the connection.
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"""
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poller = select.poll() |
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#print msgreader.peer_will_close, force
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if msgreader and msgreader.peer_will_close and not force: |
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# Wait for peer to close
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try:
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# Check whether it's actually closed
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if not SocketOperation(poller, sock, SOCKOP_RECV, 1, close_timeout): |
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return
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except (socket.error, HttpError, HttpSocketTimeout):
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# Ignore errors at this stage
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pass
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# Close the connection from our side
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try:
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SocketOperation(poller, sock, SOCKOP_SHUTDOWN, socket.SHUT_RDWR, |
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write_timeout) |
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except HttpSocketTimeout:
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raise HttpError("Timeout while shutting down connection") |
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except socket.error, err:
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raise HttpError("Error while shutting down connection: %s" % err) |
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class HttpSslParams(object): |
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"""Data class for SSL key and certificate.
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"""
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def __init__(self, ssl_key_path, ssl_cert_path): |
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"""Initializes this class.
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@type ssl_key_path: string
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@param ssl_key_path: Path to file containing SSL key in PEM format
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@type ssl_cert_path: string
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@param ssl_cert_path: Path to file containing SSL certificate in PEM format
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"""
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self.ssl_key_pem = utils.ReadFile(ssl_key_path)
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self.ssl_cert_pem = utils.ReadFile(ssl_cert_path)
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def GetKey(self): |
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return OpenSSL.crypto.load_privatekey(OpenSSL.crypto.FILETYPE_PEM,
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self.ssl_key_pem)
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def GetCertificate(self): |
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return OpenSSL.crypto.load_certificate(OpenSSL.crypto.FILETYPE_PEM,
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self.ssl_cert_pem)
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class HttpSocketBase(object): |
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"""Base class for HTTP server and client.
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"""
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def __init__(self): |
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self._using_ssl = None |
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self._ssl_params = None |
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self._ssl_key = None |
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self._ssl_cert = None |
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def _CreateSocket(self, ssl_params, ssl_verify_peer): |
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"""Creates a TCP socket and initializes SSL if needed.
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@type ssl_params: HttpSslParams
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@param ssl_params: SSL key and certificate
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@type ssl_verify_peer: bool
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@param ssl_verify_peer: Whether to require client certificate and compare
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it with our certificate
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"""
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self._ssl_params = ssl_params
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sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) |
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# Should we enable SSL?
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self._using_ssl = ssl_params is not None |
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if not self._using_ssl: |
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return sock
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self._ssl_key = ssl_params.GetKey()
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self._ssl_cert = ssl_params.GetCertificate()
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ctx = OpenSSL.SSL.Context(OpenSSL.SSL.SSLv23_METHOD) |
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ctx.set_options(OpenSSL.SSL.OP_NO_SSLv2) |
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ctx.use_privatekey(self._ssl_key)
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ctx.use_certificate(self._ssl_cert)
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ctx.check_privatekey() |
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if ssl_verify_peer:
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ctx.set_verify(OpenSSL.SSL.VERIFY_PEER | |
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OpenSSL.SSL.VERIFY_FAIL_IF_NO_PEER_CERT, |
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self._SSLVerifyCallback)
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return OpenSSL.SSL.Connection(ctx, sock)
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def _SSLVerifyCallback(self, conn, cert, errnum, errdepth, ok): |
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"""Verify the certificate provided by the peer
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We only compare fingerprints. The client must use the same certificate as
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we do on our side.
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"""
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assert self._ssl_params, "SSL not initialized" |
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return (self._ssl_cert.digest("sha1") == cert.digest("sha1") and |
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self._ssl_cert.digest("md5") == cert.digest("md5")) |
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class HttpMessage(object): |
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"""Data structure for HTTP message.
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"""
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def __init__(self): |
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self.start_line = None |
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self.headers = None |
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self.body = None |
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self.decoded_body = None |
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class HttpClientToServerStartLine(object): |
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"""Data structure for HTTP request start line.
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"""
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def __init__(self, method, path, version): |
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self.method = method
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self.path = path
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self.version = version
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def __str__(self): |
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return "%s %s %s" % (self.method, self.path, self.version) |
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class HttpServerToClientStartLine(object): |
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"""Data structure for HTTP response start line.
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"""
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def __init__(self, version, code, reason): |
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self.version = version
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self.code = code
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self.reason = reason
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def __str__(self): |
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return "%s %s %s" % (self.version, self.code, self.reason) |
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class HttpMessageWriter(object): |
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"""Writes an HTTP message to a socket.
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"""
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def __init__(self, sock, msg, write_timeout): |
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self._msg = msg
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self._PrepareMessage()
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buf = self._FormatMessage()
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poller = select.poll() |
472 |
while buf:
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# Send only 4 KB at a time
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data = buf[:4096]
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sent = SocketOperation(poller, sock, SOCKOP_SEND, data, |
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write_timeout) |
478 |
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# Remove sent bytes
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buf = buf[sent:] |
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assert not buf, "Message wasn't sent completely" |
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def _PrepareMessage(self): |
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"""Prepares the HTTP message by setting mandatory headers.
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"""
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# RFC2616, section 4.3: "The presence of a message-body in a request is
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# signaled by the inclusion of a Content-Length or Transfer-Encoding header
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# field in the request's message-headers."
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if self._msg.body: |
492 |
self._msg.headers[HTTP_CONTENT_LENGTH] = len(self._msg.body) |
493 |
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def _FormatMessage(self): |
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"""Serializes the HTTP message into a string.
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"""
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buf = StringIO() |
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# Add start line
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buf.write(str(self._msg.start_line)) |
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buf.write("\r\n")
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|
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# Add headers
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if self._msg.start_line.version != HTTP_0_9: |
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for name, value in self._msg.headers.iteritems(): |
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buf.write("%s: %s\r\n" % (name, value))
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buf.write("\r\n")
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# Add message body if needed
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if self.HasMessageBody(): |
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buf.write(self._msg.body)
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elif self._msg.body: |
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logging.warning("Ignoring message body")
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return buf.getvalue()
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def HasMessageBody(self): |
521 |
"""Checks whether the HTTP message contains a body.
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Can be overriden by subclasses.
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"""
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return bool(self._msg.body) |
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class HttpMessageReader(object): |
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"""Reads HTTP message from socket.
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"""
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# Length limits
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START_LINE_LENGTH_MAX = None
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HEADER_LENGTH_MAX = None
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# Parser state machine
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PS_START_LINE = "start-line"
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PS_HEADERS = "headers"
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PS_BODY = "entity-body"
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PS_COMPLETE = "complete"
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def __init__(self, sock, msg, read_timeout): |
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self.sock = sock
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self.msg = msg
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self.poller = select.poll()
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self.start_line_buffer = None |
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self.header_buffer = StringIO()
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self.body_buffer = StringIO()
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self.parser_status = self.PS_START_LINE |
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self.content_length = None |
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self.peer_will_close = None |
554 |
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buf = ""
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eof = False
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while self.parser_status != self.PS_COMPLETE: |
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data = SocketOperation(self.poller, sock, SOCKOP_RECV, 4096, |
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read_timeout) |
560 |
|
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if data:
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buf += data |
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else:
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eof = True
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# Do some parsing and error checking while more data arrives
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buf = self._ContinueParsing(buf, eof)
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|
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# Must be done only after the buffer has been evaluated
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# TODO: Connection-length < len(data read) and connection closed
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if (eof and |
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self.parser_status in (self.PS_START_LINE, |
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self.PS_HEADERS)):
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raise HttpError("Connection closed prematurely") |
575 |
|
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# Parse rest
|
577 |
buf = self._ContinueParsing(buf, True) |
578 |
|
579 |
assert self.parser_status == self.PS_COMPLETE |
580 |
assert not buf, "Parser didn't read full response" |
581 |
|
582 |
msg.body = self.body_buffer.getvalue()
|
583 |
|
584 |
# TODO: Content-type, error handling
|
585 |
if msg.body:
|
586 |
msg.decoded_body = HttpJsonConverter().Decode(msg.body) |
587 |
else:
|
588 |
msg.decoded_body = None
|
589 |
|
590 |
if msg.decoded_body:
|
591 |
logging.debug("Message body: %s", msg.decoded_body)
|
592 |
|
593 |
def _ContinueParsing(self, buf, eof): |
594 |
"""Main function for HTTP message state machine.
|
595 |
|
596 |
@type buf: string
|
597 |
@param buf: Receive buffer
|
598 |
@type eof: bool
|
599 |
@param eof: Whether we've reached EOF on the socket
|
600 |
@rtype: string
|
601 |
@return: Updated receive buffer
|
602 |
|
603 |
"""
|
604 |
if self.parser_status == self.PS_START_LINE: |
605 |
# Expect start line
|
606 |
while True: |
607 |
idx = buf.find("\r\n")
|
608 |
|
609 |
# RFC2616, section 4.1: "In the interest of robustness, servers SHOULD
|
610 |
# ignore any empty line(s) received where a Request-Line is expected.
|
611 |
# In other words, if the server is reading the protocol stream at the
|
612 |
# beginning of a message and receives a CRLF first, it should ignore
|
613 |
# the CRLF."
|
614 |
if idx == 0: |
615 |
# TODO: Limit number of CRLFs for safety?
|
616 |
buf = buf[:2]
|
617 |
continue
|
618 |
|
619 |
if idx > 0: |
620 |
self.start_line_buffer = buf[:idx]
|
621 |
|
622 |
self._CheckStartLineLength(len(self.start_line_buffer)) |
623 |
|
624 |
# Remove status line, including CRLF
|
625 |
buf = buf[idx + 2:]
|
626 |
|
627 |
self.msg.start_line = self.ParseStartLine(self.start_line_buffer) |
628 |
|
629 |
self.parser_status = self.PS_HEADERS |
630 |
else:
|
631 |
# Check whether incoming data is getting too large, otherwise we just
|
632 |
# fill our read buffer.
|
633 |
self._CheckStartLineLength(len(buf)) |
634 |
|
635 |
break
|
636 |
|
637 |
# TODO: Handle messages without headers
|
638 |
if self.parser_status == self.PS_HEADERS: |
639 |
# Wait for header end
|
640 |
idx = buf.find("\r\n\r\n")
|
641 |
if idx >= 0: |
642 |
self.header_buffer.write(buf[:idx + 2]) |
643 |
|
644 |
self._CheckHeaderLength(self.header_buffer.tell()) |
645 |
|
646 |
# Remove headers, including CRLF
|
647 |
buf = buf[idx + 4:]
|
648 |
|
649 |
self._ParseHeaders()
|
650 |
|
651 |
self.parser_status = self.PS_BODY |
652 |
else:
|
653 |
# Check whether incoming data is getting too large, otherwise we just
|
654 |
# fill our read buffer.
|
655 |
self._CheckHeaderLength(len(buf)) |
656 |
|
657 |
if self.parser_status == self.PS_BODY: |
658 |
# TODO: Implement max size for body_buffer
|
659 |
self.body_buffer.write(buf)
|
660 |
buf = ""
|
661 |
|
662 |
# Check whether we've read everything
|
663 |
#
|
664 |
# RFC2616, section 4.4: "When a message-body is included with a message,
|
665 |
# the transfer-length of that body is determined by one of the following
|
666 |
# [...] 5. By the server closing the connection. (Closing the connection
|
667 |
# cannot be used to indicate the end of a request body, since that would
|
668 |
# leave no possibility for the server to send back a response.)"
|
669 |
if (eof or |
670 |
self.content_length is None or |
671 |
(self.content_length is not None and |
672 |
self.body_buffer.tell() >= self.content_length)): |
673 |
self.parser_status = self.PS_COMPLETE |
674 |
|
675 |
return buf
|
676 |
|
677 |
def _CheckStartLineLength(self, length): |
678 |
"""Limits the start line buffer size.
|
679 |
|
680 |
@type length: int
|
681 |
@param length: Buffer size
|
682 |
|
683 |
"""
|
684 |
if (self.START_LINE_LENGTH_MAX is not None and |
685 |
length > self.START_LINE_LENGTH_MAX):
|
686 |
raise HttpError("Start line longer than %d chars" % |
687 |
self.START_LINE_LENGTH_MAX)
|
688 |
|
689 |
def _CheckHeaderLength(self, length): |
690 |
"""Limits the header buffer size.
|
691 |
|
692 |
@type length: int
|
693 |
@param length: Buffer size
|
694 |
|
695 |
"""
|
696 |
if (self.HEADER_LENGTH_MAX is not None and |
697 |
length > self.HEADER_LENGTH_MAX):
|
698 |
raise HttpError("Headers longer than %d chars" % self.HEADER_LENGTH_MAX) |
699 |
|
700 |
def ParseStartLine(self, start_line): |
701 |
"""Parses the start line of a message.
|
702 |
|
703 |
Must be overriden by subclass.
|
704 |
|
705 |
@type start_line: string
|
706 |
@param start_line: Start line string
|
707 |
|
708 |
"""
|
709 |
raise NotImplementedError() |
710 |
|
711 |
def _WillPeerCloseConnection(self): |
712 |
"""Evaluate whether peer will close the connection.
|
713 |
|
714 |
@rtype: bool
|
715 |
@return: Whether peer will close the connection
|
716 |
|
717 |
"""
|
718 |
# RFC2616, section 14.10: "HTTP/1.1 defines the "close" connection option
|
719 |
# for the sender to signal that the connection will be closed after
|
720 |
# completion of the response. For example,
|
721 |
#
|
722 |
# Connection: close
|
723 |
#
|
724 |
# in either the request or the response header fields indicates that the
|
725 |
# connection SHOULD NOT be considered `persistent' (section 8.1) after the
|
726 |
# current request/response is complete."
|
727 |
|
728 |
hdr_connection = self.msg.headers.get(HTTP_CONNECTION, None) |
729 |
if hdr_connection:
|
730 |
hdr_connection = hdr_connection.lower() |
731 |
|
732 |
# An HTTP/1.1 server is assumed to stay open unless explicitly closed.
|
733 |
if self.msg.start_line.version == HTTP_1_1: |
734 |
return (hdr_connection and "close" in hdr_connection) |
735 |
|
736 |
# Some HTTP/1.0 implementations have support for persistent connections,
|
737 |
# using rules different than HTTP/1.1.
|
738 |
|
739 |
# For older HTTP, Keep-Alive indicates persistent connection.
|
740 |
if self.msg.headers.get(HTTP_KEEP_ALIVE): |
741 |
return False |
742 |
|
743 |
# At least Akamai returns a "Connection: Keep-Alive" header, which was
|
744 |
# supposed to be sent by the client.
|
745 |
if hdr_connection and "keep-alive" in hdr_connection: |
746 |
return False |
747 |
|
748 |
return True |
749 |
|
750 |
def _ParseHeaders(self): |
751 |
"""Parses the headers.
|
752 |
|
753 |
This function also adjusts internal variables based on header values.
|
754 |
|
755 |
RFC2616, section 4.3: "The presence of a message-body in a request is
|
756 |
signaled by the inclusion of a Content-Length or Transfer-Encoding header
|
757 |
field in the request's message-headers."
|
758 |
|
759 |
"""
|
760 |
# Parse headers
|
761 |
self.header_buffer.seek(0, 0) |
762 |
self.msg.headers = mimetools.Message(self.header_buffer, 0) |
763 |
|
764 |
self.peer_will_close = self._WillPeerCloseConnection() |
765 |
|
766 |
# Do we have a Content-Length header?
|
767 |
hdr_content_length = self.msg.headers.get(HTTP_CONTENT_LENGTH, None) |
768 |
if hdr_content_length:
|
769 |
try:
|
770 |
self.content_length = int(hdr_content_length) |
771 |
except ValueError: |
772 |
self.content_length = None |
773 |
if self.content_length is not None and self.content_length < 0: |
774 |
self.content_length = None |
775 |
|
776 |
# if the connection remains open and a content-length was not provided,
|
777 |
# then assume that the connection WILL close.
|
778 |
if self.content_length is None: |
779 |
self.peer_will_close = True |