root / lib / http / __init__.py @ 8d0a4f99
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#
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#
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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_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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HTTP_WWW_AUTHENTICATE = "WWW-Authenticate"
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HTTP_AUTHORIZATION = "Authorization"
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HTTP_AUTHENTICATION_INFO = "Authentication-Info"
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HTTP_ALLOW = "Allow"
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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, |
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SOCKOP_HANDSHAKE) = range(4) |
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# send/receive quantum
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SOCK_BUF_SIZE = 32768
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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 HttpConnectionClosed(Exception): |
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"""Internal exception for a closed connection.
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This should only be used for internal error reporting. Only use
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it if there's no other way to report this condition.
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"""
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class HttpSessionHandshakeUnexpectedEOF(HttpError): |
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"""Internal exception for errors during SSL handshake.
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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, headers=None): |
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Exception.__init__(self) |
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self.message = message
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self.headers = headers
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class HttpBadRequest(HttpException): |
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"""400 Bad Request
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RFC2616, 10.4.1: The request could not be understood by the server
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due to malformed syntax. The client SHOULD NOT repeat the request
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without modifications.
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"""
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code = 400
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class HttpUnauthorized(HttpException): |
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"""401 Unauthorized
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RFC2616, section 10.4.2: The request requires user
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authentication. The response MUST include a WWW-Authenticate header
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field (section 14.47) containing a challenge applicable to the
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requested resource.
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"""
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code = 401
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class HttpForbidden(HttpException): |
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"""403 Forbidden
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RFC2616, 10.4.4: The server understood the request, but is refusing
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to fulfill it. Authorization will not help and the request SHOULD
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NOT be repeated.
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"""
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code = 403
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class HttpNotFound(HttpException): |
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"""404 Not Found
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RFC2616, 10.4.5: The server has not found anything matching the
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Request-URI. No indication is given of whether the condition is
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temporary or permanent.
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"""
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code = 404
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class HttpMethodNotAllowed(HttpException): |
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"""405 Method Not Allowed
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RFC2616, 10.4.6: The method specified in the Request-Line is not
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allowed for the resource identified by the Request-URI. The response
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MUST include an Allow header containing a list of valid methods for
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the requested resource.
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"""
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code = 405
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class HttpRequestTimeout(HttpException): |
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"""408 Request Timeout
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RFC2616, 10.4.9: The client did not produce a request within the
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time that the server was prepared to wait. The client MAY repeat the
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request without modifications at any later time.
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"""
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code = 408
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class HttpConflict(HttpException): |
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"""409 Conflict
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RFC2616, 10.4.10: The request could not be completed due to a
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conflict with the current state of the resource. This code is only
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allowed in situations where it is expected that the user might be
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able to resolve the conflict and resubmit the request.
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"""
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code = 409
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class HttpGone(HttpException): |
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"""410 Gone
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RFC2616, 10.4.11: The requested resource is no longer available at
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the server and no forwarding address is known. This condition is
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expected to be considered permanent.
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"""
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code = 410
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class HttpLengthRequired(HttpException): |
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"""411 Length Required
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RFC2616, 10.4.12: The server refuses to accept the request without a
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defined Content-Length. The client MAY repeat the request if it adds
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a valid Content-Length header field containing the length of the
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message-body in the request message.
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"""
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code = 411
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class HttpPreconditionFailed(HttpException): |
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"""412 Precondition Failed
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RFC2616, 10.4.13: The precondition given in one or more of the
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request-header fields evaluated to false when it was tested on the
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server.
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"""
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code = 412
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class HttpInternalServerError(HttpException): |
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"""500 Internal Server Error
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RFC2616, 10.5.1: The server encountered an unexpected condition
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which prevented it from fulfilling the request.
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"""
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code = 500
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class HttpNotImplemented(HttpException): |
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"""501 Not Implemented
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RFC2616, 10.5.2: The server does not support the functionality
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required to fulfill the request.
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"""
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code = 501
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class HttpBadGateway(HttpException): |
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"""502 Bad Gateway
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RFC2616, 10.5.3: The server, while acting as a gateway or proxy,
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received an invalid response from the upstream server it accessed in
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attempting to fulfill the request.
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"""
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code = 502
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class HttpServiceUnavailable(HttpException): |
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"""503 Service Unavailable
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RFC2616, 10.5.4: The server is currently unable to handle the
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request due to a temporary overloading or maintenance of the server.
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"""
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code = 503
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class HttpGatewayTimeout(HttpException): |
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"""504 Gateway Timeout
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RFC2616, 10.5.5: The server, while acting as a gateway or proxy, did
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not receive a timely response from the upstream server specified by
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the URI (e.g. HTTP, FTP, LDAP) or some other auxiliary server
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(e.g. DNS) it needed to access in attempting to complete the
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request.
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"""
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code = 504
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class HttpVersionNotSupported(HttpException): |
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"""505 HTTP Version Not Supported
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RFC2616, 10.5.6: The server does not support, or refuses to support,
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the HTTP protocol version that was used in the request message.
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"""
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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(sock, event, timeout): |
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"""Waits for a condition to occur on the socket.
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@type sock: socket
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@param sock: 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 = select.poll() |
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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(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 sock: socket
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@param sock: 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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@return: Return value of socket function
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"""
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# TODO: event_poll/event_check/override
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if op in (SOCKOP_SEND, SOCKOP_HANDSHAKE): |
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event_poll = select.POLLOUT |
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elif op == SOCKOP_RECV:
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event_poll = select.POLLIN |
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elif op == SOCKOP_SHUTDOWN:
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event_poll = 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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# Handshake is only supported by SSL sockets
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if (op == SOCKOP_HANDSHAKE and |
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not isinstance(sock, OpenSSL.SSL.ConnectionType)): |
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return
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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, SOCKOP_HANDSHAKE): |
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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(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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elif op == SOCKOP_HANDSHAKE:
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return sock.do_handshake()
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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.ZeroReturnError, err:
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# SSL Connection has been closed. In SSL 3.0 and TLS 1.0, this only
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# occurs if a closure alert has occurred in the protocol, i.e. the
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# connection has been closed cleanly. Note that this does not
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# necessarily mean that the transport layer (e.g. a socket) has been
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# closed.
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if op == SOCKOP_SEND:
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# Can happen during a renegotiation
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raise HttpConnectionClosed(err.args)
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elif op == SOCKOP_RECV:
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return "" |
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# SSL_shutdown shouldn't return SSL_ERROR_ZERO_RETURN
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raise socket.error(err.args)
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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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if err.args == (-1, _SSL_UNEXPECTED_EOF): |
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if op == SOCKOP_RECV:
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return "" |
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elif op == SOCKOP_HANDSHAKE:
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# Can happen if peer disconnects directly after the connection is
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# opened.
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raise HttpSessionHandshakeUnexpectedEOF(err.args)
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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(sock, close_timeout, write_timeout, msgreader, force): |
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"""Closes the connection.
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491 |
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@type sock: socket
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@param sock: Socket to be shut down
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@type close_timeout: float
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@param close_timeout: How long to wait for the peer to close
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the connection
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@type write_timeout: float
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@param write_timeout: Write timeout for shutdown
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@type msgreader: http.HttpMessageReader
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@param msgreader: Request message reader, used to determine whether
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peer should close connection
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@type force: bool
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@param force: Whether to forcibly close the connection without
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waiting for peer
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"""
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#print msgreader.peer_will_close, force
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if msgreader and msgreader.peer_will_close and not force: |
509 |
# 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(sock, SOCKOP_RECV, 1, close_timeout): |
513 |
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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# We don't care about the return value, see NOTES in SSL_shutdown(3).
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SocketOperation(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") |
525 |
except socket.error, err:
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# Ignore ENOTCONN
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if not (err.args and err.args[0] == errno.ENOTCONN): |
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raise HttpError("Error while shutting down connection: %s" % err) |
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def Handshake(sock, write_timeout): |
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"""Shakes peer's hands.
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@type sock: socket
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@param sock: Socket to be shut down
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@type write_timeout: float
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@param write_timeout: Write timeout for handshake
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"""
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try:
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return SocketOperation(sock, SOCKOP_HANDSHAKE, None, write_timeout) |
542 |
except HttpSocketTimeout:
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raise HttpError("Timeout during SSL handshake") |
544 |
except socket.error, err:
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raise HttpError("Error in SSL handshake: %s" % err) |
546 |
|
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|
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def InitSsl(): |
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"""Initializes the SSL infrastructure.
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550 |
|
551 |
This function is idempotent.
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|
553 |
"""
|
554 |
if not OpenSSL.rand.status(): |
555 |
raise EnvironmentError("OpenSSL could not collect enough entropy" |
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" for the PRNG")
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|
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# TODO: Maybe add some additional seeding for OpenSSL's PRNG
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|
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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): |
566 |
"""Initializes this class.
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|
568 |
@type ssl_key_path: string
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569 |
@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
|
572 |
in PEM format
|
573 |
|
574 |
"""
|
575 |
self.ssl_key_pem = utils.ReadFile(ssl_key_path)
|
576 |
self.ssl_cert_pem = utils.ReadFile(ssl_cert_path)
|
577 |
|
578 |
def GetKey(self): |
579 |
return OpenSSL.crypto.load_privatekey(OpenSSL.crypto.FILETYPE_PEM,
|
580 |
self.ssl_key_pem)
|
581 |
|
582 |
def GetCertificate(self): |
583 |
return OpenSSL.crypto.load_certificate(OpenSSL.crypto.FILETYPE_PEM,
|
584 |
self.ssl_cert_pem)
|
585 |
|
586 |
|
587 |
class HttpBase(object): |
588 |
"""Base class for HTTP server and client.
|
589 |
|
590 |
"""
|
591 |
def __init__(self): |
592 |
self.using_ssl = None |
593 |
self._ssl_params = None |
594 |
self._ssl_key = None |
595 |
self._ssl_cert = None |
596 |
|
597 |
def _CreateSocket(self, ssl_params, ssl_verify_peer): |
598 |
"""Creates a TCP socket and initializes SSL if needed.
|
599 |
|
600 |
@type ssl_params: HttpSslParams
|
601 |
@param ssl_params: SSL key and certificate
|
602 |
@type ssl_verify_peer: bool
|
603 |
@param ssl_verify_peer: Whether to require client certificate
|
604 |
and compare it with our certificate
|
605 |
|
606 |
"""
|
607 |
self._ssl_params = ssl_params
|
608 |
|
609 |
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) |
610 |
|
611 |
# Should we enable SSL?
|
612 |
self.using_ssl = ssl_params is not None |
613 |
|
614 |
if not self.using_ssl: |
615 |
return sock
|
616 |
|
617 |
self._ssl_key = ssl_params.GetKey()
|
618 |
self._ssl_cert = ssl_params.GetCertificate()
|
619 |
|
620 |
ctx = OpenSSL.SSL.Context(OpenSSL.SSL.SSLv23_METHOD) |
621 |
ctx.set_options(OpenSSL.SSL.OP_NO_SSLv2) |
622 |
|
623 |
ctx.use_privatekey(self._ssl_key)
|
624 |
ctx.use_certificate(self._ssl_cert)
|
625 |
ctx.check_privatekey() |
626 |
|
627 |
if ssl_verify_peer:
|
628 |
ctx.set_verify(OpenSSL.SSL.VERIFY_PEER | |
629 |
OpenSSL.SSL.VERIFY_FAIL_IF_NO_PEER_CERT, |
630 |
self._SSLVerifyCallback)
|
631 |
|
632 |
return OpenSSL.SSL.Connection(ctx, sock)
|
633 |
|
634 |
def _SSLVerifyCallback(self, conn, cert, errnum, errdepth, ok): |
635 |
"""Verify the certificate provided by the peer
|
636 |
|
637 |
We only compare fingerprints. The client must use the same certificate as
|
638 |
we do on our side.
|
639 |
|
640 |
"""
|
641 |
assert self._ssl_params, "SSL not initialized" |
642 |
|
643 |
return (self._ssl_cert.digest("sha1") == cert.digest("sha1") and |
644 |
self._ssl_cert.digest("md5") == cert.digest("md5")) |
645 |
|
646 |
|
647 |
class HttpMessage(object): |
648 |
"""Data structure for HTTP message.
|
649 |
|
650 |
"""
|
651 |
def __init__(self): |
652 |
self.start_line = None |
653 |
self.headers = None |
654 |
self.body = None |
655 |
self.decoded_body = None |
656 |
|
657 |
|
658 |
class HttpClientToServerStartLine(object): |
659 |
"""Data structure for HTTP request start line.
|
660 |
|
661 |
"""
|
662 |
def __init__(self, method, path, version): |
663 |
self.method = method
|
664 |
self.path = path
|
665 |
self.version = version
|
666 |
|
667 |
def __str__(self): |
668 |
return "%s %s %s" % (self.method, self.path, self.version) |
669 |
|
670 |
|
671 |
class HttpServerToClientStartLine(object): |
672 |
"""Data structure for HTTP response start line.
|
673 |
|
674 |
"""
|
675 |
def __init__(self, version, code, reason): |
676 |
self.version = version
|
677 |
self.code = code
|
678 |
self.reason = reason
|
679 |
|
680 |
def __str__(self): |
681 |
return "%s %s %s" % (self.version, self.code, self.reason) |
682 |
|
683 |
|
684 |
class HttpMessageWriter(object): |
685 |
"""Writes an HTTP message to a socket.
|
686 |
|
687 |
"""
|
688 |
def __init__(self, sock, msg, write_timeout): |
689 |
"""Initializes this class and writes an HTTP message to a socket.
|
690 |
|
691 |
@type sock: socket
|
692 |
@param sock: Socket to be written to
|
693 |
@type msg: http.HttpMessage
|
694 |
@param msg: HTTP message to be written
|
695 |
@type write_timeout: float
|
696 |
@param write_timeout: Write timeout for socket
|
697 |
|
698 |
"""
|
699 |
self._msg = msg
|
700 |
|
701 |
self._PrepareMessage()
|
702 |
|
703 |
buf = self._FormatMessage()
|
704 |
|
705 |
pos = 0
|
706 |
end = len(buf)
|
707 |
while pos < end:
|
708 |
# Send only SOCK_BUF_SIZE bytes at a time
|
709 |
data = buf[pos:(pos + SOCK_BUF_SIZE)] |
710 |
|
711 |
sent = SocketOperation(sock, SOCKOP_SEND, data, write_timeout) |
712 |
|
713 |
# Remove sent bytes
|
714 |
pos += sent |
715 |
|
716 |
assert pos == end, "Message wasn't sent completely" |
717 |
|
718 |
def _PrepareMessage(self): |
719 |
"""Prepares the HTTP message by setting mandatory headers.
|
720 |
|
721 |
"""
|
722 |
# RFC2616, section 4.3: "The presence of a message-body in a request is
|
723 |
# signaled by the inclusion of a Content-Length or Transfer-Encoding header
|
724 |
# field in the request's message-headers."
|
725 |
if self._msg.body: |
726 |
self._msg.headers[HTTP_CONTENT_LENGTH] = len(self._msg.body) |
727 |
|
728 |
def _FormatMessage(self): |
729 |
"""Serializes the HTTP message into a string.
|
730 |
|
731 |
"""
|
732 |
buf = StringIO() |
733 |
|
734 |
# Add start line
|
735 |
buf.write(str(self._msg.start_line)) |
736 |
buf.write("\r\n")
|
737 |
|
738 |
# Add headers
|
739 |
if self._msg.start_line.version != HTTP_0_9: |
740 |
for name, value in self._msg.headers.iteritems(): |
741 |
buf.write("%s: %s\r\n" % (name, value))
|
742 |
|
743 |
buf.write("\r\n")
|
744 |
|
745 |
# Add message body if needed
|
746 |
if self.HasMessageBody(): |
747 |
buf.write(self._msg.body)
|
748 |
|
749 |
elif self._msg.body: |
750 |
logging.warning("Ignoring message body")
|
751 |
|
752 |
return buf.getvalue()
|
753 |
|
754 |
def HasMessageBody(self): |
755 |
"""Checks whether the HTTP message contains a body.
|
756 |
|
757 |
Can be overridden by subclasses.
|
758 |
|
759 |
"""
|
760 |
return bool(self._msg.body) |
761 |
|
762 |
|
763 |
class HttpMessageReader(object): |
764 |
"""Reads HTTP message from socket.
|
765 |
|
766 |
"""
|
767 |
# Length limits
|
768 |
START_LINE_LENGTH_MAX = None
|
769 |
HEADER_LENGTH_MAX = None
|
770 |
|
771 |
# Parser state machine
|
772 |
PS_START_LINE = "start-line"
|
773 |
PS_HEADERS = "headers"
|
774 |
PS_BODY = "entity-body"
|
775 |
PS_COMPLETE = "complete"
|
776 |
|
777 |
def __init__(self, sock, msg, read_timeout): |
778 |
"""Reads an HTTP message from a socket.
|
779 |
|
780 |
@type sock: socket
|
781 |
@param sock: Socket to be read from
|
782 |
@type msg: http.HttpMessage
|
783 |
@param msg: Object for the read message
|
784 |
@type read_timeout: float
|
785 |
@param read_timeout: Read timeout for socket
|
786 |
|
787 |
"""
|
788 |
self.sock = sock
|
789 |
self.msg = msg
|
790 |
|
791 |
self.start_line_buffer = None |
792 |
self.header_buffer = StringIO()
|
793 |
self.body_buffer = StringIO()
|
794 |
self.parser_status = self.PS_START_LINE |
795 |
self.content_length = None |
796 |
self.peer_will_close = None |
797 |
|
798 |
buf = ""
|
799 |
eof = False
|
800 |
while self.parser_status != self.PS_COMPLETE: |
801 |
# TODO: Don't read more than necessary (Content-Length), otherwise
|
802 |
# data might be lost and/or an error could occur
|
803 |
data = SocketOperation(sock, SOCKOP_RECV, SOCK_BUF_SIZE, read_timeout) |
804 |
|
805 |
if data:
|
806 |
buf += data |
807 |
else:
|
808 |
eof = True
|
809 |
|
810 |
# Do some parsing and error checking while more data arrives
|
811 |
buf = self._ContinueParsing(buf, eof)
|
812 |
|
813 |
# Must be done only after the buffer has been evaluated
|
814 |
# TODO: Connection-length < len(data read) and connection closed
|
815 |
if (eof and |
816 |
self.parser_status in (self.PS_START_LINE, |
817 |
self.PS_HEADERS)):
|
818 |
raise HttpError("Connection closed prematurely") |
819 |
|
820 |
# Parse rest
|
821 |
buf = self._ContinueParsing(buf, True) |
822 |
|
823 |
assert self.parser_status == self.PS_COMPLETE |
824 |
assert not buf, "Parser didn't read full response" |
825 |
|
826 |
msg.body = self.body_buffer.getvalue()
|
827 |
|
828 |
# TODO: Content-type, error handling
|
829 |
if msg.body:
|
830 |
msg.decoded_body = HttpJsonConverter().Decode(msg.body) |
831 |
else:
|
832 |
msg.decoded_body = None
|
833 |
|
834 |
if msg.decoded_body:
|
835 |
logging.debug("Message body: %s", msg.decoded_body)
|
836 |
|
837 |
def _ContinueParsing(self, buf, eof): |
838 |
"""Main function for HTTP message state machine.
|
839 |
|
840 |
@type buf: string
|
841 |
@param buf: Receive buffer
|
842 |
@type eof: bool
|
843 |
@param eof: Whether we've reached EOF on the socket
|
844 |
@rtype: string
|
845 |
@return: Updated receive buffer
|
846 |
|
847 |
"""
|
848 |
# TODO: Use offset instead of slicing when possible
|
849 |
if self.parser_status == self.PS_START_LINE: |
850 |
# Expect start line
|
851 |
while True: |
852 |
idx = buf.find("\r\n")
|
853 |
|
854 |
# RFC2616, section 4.1: "In the interest of robustness, servers SHOULD
|
855 |
# ignore any empty line(s) received where a Request-Line is expected.
|
856 |
# In other words, if the server is reading the protocol stream at the
|
857 |
# beginning of a message and receives a CRLF first, it should ignore
|
858 |
# the CRLF."
|
859 |
if idx == 0: |
860 |
# TODO: Limit number of CRLFs/empty lines for safety?
|
861 |
buf = buf[:2]
|
862 |
continue
|
863 |
|
864 |
if idx > 0: |
865 |
self.start_line_buffer = buf[:idx]
|
866 |
|
867 |
self._CheckStartLineLength(len(self.start_line_buffer)) |
868 |
|
869 |
# Remove status line, including CRLF
|
870 |
buf = buf[idx + 2:]
|
871 |
|
872 |
self.msg.start_line = self.ParseStartLine(self.start_line_buffer) |
873 |
|
874 |
self.parser_status = self.PS_HEADERS |
875 |
else:
|
876 |
# Check whether incoming data is getting too large, otherwise we just
|
877 |
# fill our read buffer.
|
878 |
self._CheckStartLineLength(len(buf)) |
879 |
|
880 |
break
|
881 |
|
882 |
# TODO: Handle messages without headers
|
883 |
if self.parser_status == self.PS_HEADERS: |
884 |
# Wait for header end
|
885 |
idx = buf.find("\r\n\r\n")
|
886 |
if idx >= 0: |
887 |
self.header_buffer.write(buf[:idx + 2]) |
888 |
|
889 |
self._CheckHeaderLength(self.header_buffer.tell()) |
890 |
|
891 |
# Remove headers, including CRLF
|
892 |
buf = buf[idx + 4:]
|
893 |
|
894 |
self._ParseHeaders()
|
895 |
|
896 |
self.parser_status = self.PS_BODY |
897 |
else:
|
898 |
# Check whether incoming data is getting too large, otherwise we just
|
899 |
# fill our read buffer.
|
900 |
self._CheckHeaderLength(len(buf)) |
901 |
|
902 |
if self.parser_status == self.PS_BODY: |
903 |
# TODO: Implement max size for body_buffer
|
904 |
self.body_buffer.write(buf)
|
905 |
buf = ""
|
906 |
|
907 |
# Check whether we've read everything
|
908 |
#
|
909 |
# RFC2616, section 4.4: "When a message-body is included with a message,
|
910 |
# the transfer-length of that body is determined by one of the following
|
911 |
# [...] 5. By the server closing the connection. (Closing the connection
|
912 |
# cannot be used to indicate the end of a request body, since that would
|
913 |
# leave no possibility for the server to send back a response.)"
|
914 |
#
|
915 |
# TODO: Error when buffer length > Content-Length header
|
916 |
if (eof or |
917 |
self.content_length is None or |
918 |
(self.content_length is not None and |
919 |
self.body_buffer.tell() >= self.content_length)): |
920 |
self.parser_status = self.PS_COMPLETE |
921 |
|
922 |
return buf
|
923 |
|
924 |
def _CheckStartLineLength(self, length): |
925 |
"""Limits the start line buffer size.
|
926 |
|
927 |
@type length: int
|
928 |
@param length: Buffer size
|
929 |
|
930 |
"""
|
931 |
if (self.START_LINE_LENGTH_MAX is not None and |
932 |
length > self.START_LINE_LENGTH_MAX):
|
933 |
raise HttpError("Start line longer than %d chars" % |
934 |
self.START_LINE_LENGTH_MAX)
|
935 |
|
936 |
def _CheckHeaderLength(self, length): |
937 |
"""Limits the header buffer size.
|
938 |
|
939 |
@type length: int
|
940 |
@param length: Buffer size
|
941 |
|
942 |
"""
|
943 |
if (self.HEADER_LENGTH_MAX is not None and |
944 |
length > self.HEADER_LENGTH_MAX):
|
945 |
raise HttpError("Headers longer than %d chars" % self.HEADER_LENGTH_MAX) |
946 |
|
947 |
def ParseStartLine(self, start_line): |
948 |
"""Parses the start line of a message.
|
949 |
|
950 |
Must be overridden by subclass.
|
951 |
|
952 |
@type start_line: string
|
953 |
@param start_line: Start line string
|
954 |
|
955 |
"""
|
956 |
raise NotImplementedError() |
957 |
|
958 |
def _WillPeerCloseConnection(self): |
959 |
"""Evaluate whether peer will close the connection.
|
960 |
|
961 |
@rtype: bool
|
962 |
@return: Whether peer will close the connection
|
963 |
|
964 |
"""
|
965 |
# RFC2616, section 14.10: "HTTP/1.1 defines the "close" connection option
|
966 |
# for the sender to signal that the connection will be closed after
|
967 |
# completion of the response. For example,
|
968 |
#
|
969 |
# Connection: close
|
970 |
#
|
971 |
# in either the request or the response header fields indicates that the
|
972 |
# connection SHOULD NOT be considered `persistent' (section 8.1) after the
|
973 |
# current request/response is complete."
|
974 |
|
975 |
hdr_connection = self.msg.headers.get(HTTP_CONNECTION, None) |
976 |
if hdr_connection:
|
977 |
hdr_connection = hdr_connection.lower() |
978 |
|
979 |
# An HTTP/1.1 server is assumed to stay open unless explicitly closed.
|
980 |
if self.msg.start_line.version == HTTP_1_1: |
981 |
return (hdr_connection and "close" in hdr_connection) |
982 |
|
983 |
# Some HTTP/1.0 implementations have support for persistent connections,
|
984 |
# using rules different than HTTP/1.1.
|
985 |
|
986 |
# For older HTTP, Keep-Alive indicates persistent connection.
|
987 |
if self.msg.headers.get(HTTP_KEEP_ALIVE): |
988 |
return False |
989 |
|
990 |
# At least Akamai returns a "Connection: Keep-Alive" header, which was
|
991 |
# supposed to be sent by the client.
|
992 |
if hdr_connection and "keep-alive" in hdr_connection: |
993 |
return False |
994 |
|
995 |
return True |
996 |
|
997 |
def _ParseHeaders(self): |
998 |
"""Parses the headers.
|
999 |
|
1000 |
This function also adjusts internal variables based on header values.
|
1001 |
|
1002 |
RFC2616, section 4.3: The presence of a message-body in a request is
|
1003 |
signaled by the inclusion of a Content-Length or Transfer-Encoding header
|
1004 |
field in the request's message-headers.
|
1005 |
|
1006 |
"""
|
1007 |
# Parse headers
|
1008 |
self.header_buffer.seek(0, 0) |
1009 |
self.msg.headers = mimetools.Message(self.header_buffer, 0) |
1010 |
|
1011 |
self.peer_will_close = self._WillPeerCloseConnection() |
1012 |
|
1013 |
# Do we have a Content-Length header?
|
1014 |
hdr_content_length = self.msg.headers.get(HTTP_CONTENT_LENGTH, None) |
1015 |
if hdr_content_length:
|
1016 |
try:
|
1017 |
self.content_length = int(hdr_content_length) |
1018 |
except ValueError: |
1019 |
self.content_length = None |
1020 |
if self.content_length is not None and self.content_length < 0: |
1021 |
self.content_length = None |
1022 |
|
1023 |
# if the connection remains open and a content-length was not provided,
|
1024 |
# then assume that the connection WILL close.
|
1025 |
if self.content_length is None: |
1026 |
self.peer_will_close = True |