585 lines
22 KiB
Python
585 lines
22 KiB
Python
# Copyright (c) 2012-2013 Mitch Garnaat http://garnaat.org/
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# Copyright 2012-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"). You
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# may not use this file except in compliance with the License. A copy of
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# the License is located at
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#
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# http://aws.amazon.com/apache2.0/
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#
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# or in the "license" file accompanying this file. This file is
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# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
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# ANY KIND, either express or implied. See the License for the specific
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# language governing permissions and limitations under the License.
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import sys
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import logging
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import functools
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import socket
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import collections
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import urllib3.util
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from urllib3.connection import VerifiedHTTPSConnection
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from urllib3.connection import HTTPConnection
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from urllib3.connectionpool import HTTPConnectionPool
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from urllib3.connectionpool import HTTPSConnectionPool
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import botocore.utils
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from botocore.compat import six
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from botocore.compat import HTTPHeaders, HTTPResponse, urlunsplit, urlsplit, \
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urlencode
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from botocore.exceptions import UnseekableStreamError
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logger = logging.getLogger(__name__)
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class AWSHTTPResponse(HTTPResponse):
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# The *args, **kwargs is used because the args are slightly
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# different in py2.6 than in py2.7/py3.
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def __init__(self, *args, **kwargs):
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self._status_tuple = kwargs.pop('status_tuple')
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HTTPResponse.__init__(self, *args, **kwargs)
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def _read_status(self):
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if self._status_tuple is not None:
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status_tuple = self._status_tuple
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self._status_tuple = None
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return status_tuple
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else:
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return HTTPResponse._read_status(self)
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class AWSConnection(object):
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"""Mixin for HTTPConnection that supports Expect 100-continue.
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This when mixed with a subclass of httplib.HTTPConnection (though
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technically we subclass from urllib3, which subclasses
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httplib.HTTPConnection) and we only override this class to support Expect
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100-continue, which we need for S3. As far as I can tell, this is
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general purpose enough to not be specific to S3, but I'm being
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tentative and keeping it in botocore because I've only tested
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this against AWS services.
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"""
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def __init__(self, *args, **kwargs):
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super(AWSConnection, self).__init__(*args, **kwargs)
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self._original_response_cls = self.response_class
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# We'd ideally hook into httplib's states, but they're all
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# __mangled_vars so we use our own state var. This variable is set
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# when we receive an early response from the server. If this value is
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# set to True, any calls to send() are noops. This value is reset to
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# false every time _send_request is called. This is to workaround the
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# fact that py2.6 (and only py2.6) has a separate send() call for the
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# body in _send_request, as opposed to endheaders(), which is where the
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# body is sent in all versions > 2.6.
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self._response_received = False
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self._expect_header_set = False
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def close(self):
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super(AWSConnection, self).close()
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# Reset all of our instance state we were tracking.
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self._response_received = False
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self._expect_header_set = False
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self.response_class = self._original_response_cls
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def _tunnel(self):
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# Works around a bug in py26 which is fixed in later versions of
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# python. Bug involves hitting an infinite loop if readline() returns
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# nothing as opposed to just ``\r\n``.
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# As much as I don't like having if py2: <foo> code blocks, this seems
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# the cleanest way to handle this workaround. Fortunately, the
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# difference from py26 to py3 is very minimal. We're essentially
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# just overriding the while loop.
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if sys.version_info[:2] != (2, 6):
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return super(AWSConnection, self)._tunnel()
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# Otherwise we workaround the issue.
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self._set_hostport(self._tunnel_host, self._tunnel_port)
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self.send("CONNECT %s:%d HTTP/1.0\r\n" % (self.host, self.port))
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for header, value in self._tunnel_headers.iteritems():
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self.send("%s: %s\r\n" % (header, value))
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self.send("\r\n")
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response = self.response_class(self.sock, strict=self.strict,
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method=self._method)
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(version, code, message) = response._read_status()
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if code != 200:
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self.close()
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raise socket.error("Tunnel connection failed: %d %s" %
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(code, message.strip()))
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while True:
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line = response.fp.readline()
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if not line:
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break
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if line in (b'\r\n', b'\n', b''):
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break
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def _send_request(self, method, url, body, headers, *args, **kwargs):
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self._response_received = False
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if headers.get('Expect', b'') == b'100-continue':
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self._expect_header_set = True
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else:
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self._expect_header_set = False
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self.response_class = self._original_response_cls
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rval = super(AWSConnection, self)._send_request(
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method, url, body, headers, *args, **kwargs)
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self._expect_header_set = False
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return rval
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def _convert_to_bytes(self, mixed_buffer):
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# Take a list of mixed str/bytes and convert it
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# all into a single bytestring.
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# Any six.text_types will be encoded as utf-8.
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bytes_buffer = []
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for chunk in mixed_buffer:
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if isinstance(chunk, six.text_type):
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bytes_buffer.append(chunk.encode('utf-8'))
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else:
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bytes_buffer.append(chunk)
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msg = b"\r\n".join(bytes_buffer)
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return msg
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def _send_output(self, message_body=None, *args, **kwargs):
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self._buffer.extend((b"", b""))
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msg = self._convert_to_bytes(self._buffer)
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del self._buffer[:]
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# If msg and message_body are sent in a single send() call,
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# it will avoid performance problems caused by the interaction
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# between delayed ack and the Nagle algorithm.
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if isinstance(message_body, bytes):
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msg += message_body
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message_body = None
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self.send(msg)
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if self._expect_header_set:
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# This is our custom behavior. If the Expect header was
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# set, it will trigger this custom behavior.
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logger.debug("Waiting for 100 Continue response.")
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# Wait for 1 second for the server to send a response.
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if urllib3.util.wait_for_read(self.sock, 1):
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self._handle_expect_response(message_body)
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return
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else:
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# From the RFC:
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# Because of the presence of older implementations, the
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# protocol allows ambiguous situations in which a client may
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# send "Expect: 100-continue" without receiving either a 417
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# (Expectation Failed) status or a 100 (Continue) status.
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# Therefore, when a client sends this header field to an origin
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# server (possibly via a proxy) from which it has never seen a
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# 100 (Continue) status, the client SHOULD NOT wait for an
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# indefinite period before sending the request body.
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logger.debug("No response seen from server, continuing to "
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"send the response body.")
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if message_body is not None:
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# message_body was not a string (i.e. it is a file), and
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# we must run the risk of Nagle.
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self.send(message_body)
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def _consume_headers(self, fp):
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# Most servers (including S3) will just return
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# the CLRF after the 100 continue response. However,
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# some servers (I've specifically seen this for squid when
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# used as a straight HTTP proxy) will also inject a
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# Connection: keep-alive header. To account for this
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# we'll read until we read '\r\n', and ignore any headers
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# that come immediately after the 100 continue response.
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current = None
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while current != b'\r\n':
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current = fp.readline()
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def _handle_expect_response(self, message_body):
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# This is called when we sent the request headers containing
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# an Expect: 100-continue header and received a response.
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# We now need to figure out what to do.
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fp = self.sock.makefile('rb', 0)
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try:
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maybe_status_line = fp.readline()
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parts = maybe_status_line.split(None, 2)
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if self._is_100_continue_status(maybe_status_line):
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self._consume_headers(fp)
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logger.debug("100 Continue response seen, "
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"now sending request body.")
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self._send_message_body(message_body)
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elif len(parts) == 3 and parts[0].startswith(b'HTTP/'):
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# From the RFC:
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# Requirements for HTTP/1.1 origin servers:
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#
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# - Upon receiving a request which includes an Expect
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# request-header field with the "100-continue"
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# expectation, an origin server MUST either respond with
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# 100 (Continue) status and continue to read from the
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# input stream, or respond with a final status code.
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#
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# So if we don't get a 100 Continue response, then
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# whatever the server has sent back is the final response
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# and don't send the message_body.
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logger.debug("Received a non 100 Continue response "
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"from the server, NOT sending request body.")
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status_tuple = (parts[0].decode('ascii'),
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int(parts[1]), parts[2].decode('ascii'))
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response_class = functools.partial(
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AWSHTTPResponse, status_tuple=status_tuple)
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self.response_class = response_class
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self._response_received = True
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finally:
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fp.close()
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def _send_message_body(self, message_body):
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if message_body is not None:
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self.send(message_body)
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def send(self, str):
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if self._response_received:
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logger.debug("send() called, but reseponse already received. "
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"Not sending data.")
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return
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return super(AWSConnection, self).send(str)
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def _is_100_continue_status(self, maybe_status_line):
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parts = maybe_status_line.split(None, 2)
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# Check for HTTP/<version> 100 Continue\r\n
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return (
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len(parts) >= 3 and parts[0].startswith(b'HTTP/') and
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parts[1] == b'100')
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class AWSHTTPConnection(AWSConnection, HTTPConnection):
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""" An HTTPConnection that supports 100 Continue behavior. """
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class AWSHTTPSConnection(AWSConnection, VerifiedHTTPSConnection):
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""" An HTTPSConnection that supports 100 Continue behavior. """
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class AWSHTTPConnectionPool(HTTPConnectionPool):
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ConnectionCls = AWSHTTPConnection
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class AWSHTTPSConnectionPool(HTTPSConnectionPool):
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ConnectionCls = AWSHTTPSConnection
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def prepare_request_dict(request_dict, endpoint_url, context=None,
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user_agent=None):
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"""
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This method prepares a request dict to be created into an
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AWSRequestObject. This prepares the request dict by adding the
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url and the user agent to the request dict.
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:type request_dict: dict
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:param request_dict: The request dict (created from the
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``serialize`` module).
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:type user_agent: string
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:param user_agent: The user agent to use for this request.
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:type endpoint_url: string
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:param endpoint_url: The full endpoint url, which contains at least
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the scheme, the hostname, and optionally any path components.
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"""
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r = request_dict
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if user_agent is not None:
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headers = r['headers']
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headers['User-Agent'] = user_agent
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url = _urljoin(endpoint_url, r['url_path'])
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if r['query_string']:
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# NOTE: This is to avoid circular import with utils. This is being
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# done to avoid moving classes to different modules as to not cause
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# breaking chainges.
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percent_encode_sequence = botocore.utils.percent_encode_sequence
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encoded_query_string = percent_encode_sequence(r['query_string'])
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if '?' not in url:
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url += '?%s' % encoded_query_string
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else:
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url += '&%s' % encoded_query_string
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r['url'] = url
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r['context'] = context
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if context is None:
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r['context'] = {}
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def create_request_object(request_dict):
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"""
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This method takes a request dict and creates an AWSRequest object
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from it.
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:type request_dict: dict
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:param request_dict: The request dict (created from the
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``prepare_request_dict`` method).
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:rtype: ``botocore.awsrequest.AWSRequest``
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:return: An AWSRequest object based on the request_dict.
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"""
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r = request_dict
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request_object = AWSRequest(
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method=r['method'], url=r['url'], data=r['body'], headers=r['headers'])
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request_object.context.update(r['context'])
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return request_object
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def _urljoin(endpoint_url, url_path):
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p = urlsplit(endpoint_url)
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# <part> - <index>
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# scheme - p[0]
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# netloc - p[1]
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# path - p[2]
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# query - p[3]
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# fragment - p[4]
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if not url_path or url_path == '/':
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# If there's no path component, ensure the URL ends with
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# a '/' for backwards compatibility.
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if not p[2]:
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return endpoint_url + '/'
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return endpoint_url
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if p[2].endswith('/') and url_path.startswith('/'):
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new_path = p[2][:-1] + url_path
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else:
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new_path = p[2] + url_path
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reconstructed = urlunsplit((p[0], p[1], new_path, p[3], p[4]))
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return reconstructed
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class AWSRequest(object):
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"""Represents the elements of an HTTP request.
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This class is originally inspired by requests.models.Request, but has been
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boiled down to meet the specific use cases in botocore. That being said this
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class (even in requests) is effectively a named-tuple.
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"""
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def __init__(self,
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method=None,
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url=None,
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headers=None,
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data=None,
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params=None,
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auth_path=None,
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stream_output=False):
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# Default empty dicts for dict params.
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params = {} if params is None else params
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self.method = method
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self.url = url
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self.headers = HTTPHeaders()
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self.data = data
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self.params = params
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self.auth_path = auth_path
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self.stream_output = stream_output
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if headers is not None:
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for key, value in headers.items():
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self.headers[key] = value
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# This is a dictionary to hold information that is used when
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# processing the request. What is inside of ``context`` is open-ended.
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# For example, it may have a timestamp key that is used for holding
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# what the timestamp is when signing the request. Note that none
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# of the information that is inside of ``context`` is directly
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# sent over the wire; the information is only used to assist in
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# creating what is sent over the wire.
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self.context = {}
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def prepare(self):
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"""Constructs a :class:`AWSPreparedRequest <AWSPreparedRequest>`."""
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return AWSPreparedRequest(self)
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@property
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def body(self):
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p = AWSPreparedRequest(self)
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p.prepare_body(self.data)
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if isinstance(p.body, six.text_type):
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p.body = p.body.encode('utf-8')
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return p.body
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class AWSPreparedRequest(object):
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"""Represents a prepared request.
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This class is originally inspired by requests.models.PreparedRequest, but
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has been boiled down to meet the specific use cases in botocore. Of note
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there are the following differences:
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This class does not heavily prepare the URL. Requests performed many
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validations and corrections to ensure the URL is properly formatted.
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Botocore either performs these validations elsewhere or otherwise
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consistently provides well formatted URLs.
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This class does not heavily prepare the body. Body preperation is
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simple and supports only the cases that we document: bytes and
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file-like objects to determine the content-length. This will also
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additionally prepare a body that is a dict to be url encoded params
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string as some signers rely on this. Finally, this class does not
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support multipart file uploads.
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This class does not prepare the method, auth or cookies.
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:ivar method: HTTP Method
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:ivar url: The full url
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:ivar headers: The HTTP headers to send.
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:ivar body: The HTTP body.
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:ivar stream_output: If the response for this request should be streamed.
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:ivar original: The original AWSRequest
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"""
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def __init__(self, original):
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self.method = original.method
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self.prepare_url(original.url, original.params)
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self.prepare_headers(original.headers)
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self.prepare_body(original.data)
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self.stream_output = original.stream_output
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self.original = original
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def __repr__(self):
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fmt = (
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'<AWSPreparedRequest stream_output=%s, method=%s, url=%s, '
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'headers=%s>'
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)
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return fmt % (self.stream_output, self.method, self.url, self.headers)
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def reset_stream(self):
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# Trying to reset a stream when there is a no stream will
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# just immediately return. It's not an error, it will produce
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# the same result as if we had actually reset the stream (we'll send
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# the entire body contents again if we need to).
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# Same case if the body is a string/bytes/bytearray type.
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non_seekable_types = (six.binary_type, six.text_type, bytearray)
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if self.body is None or isinstance(self.body, non_seekable_types):
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return
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try:
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logger.debug("Rewinding stream: %s", self.body)
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self.body.seek(0)
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except Exception as e:
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logger.debug("Unable to rewind stream: %s", e)
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raise UnseekableStreamError(stream_object=self.body)
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def prepare_url(self, url, params):
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if params:
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params = urlencode(list(params.items()), doseq=True)
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self.url = '%s?%s' % (url, params)
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else:
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self.url = url
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def prepare_headers(self, headers):
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headers = headers or {}
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self.headers = HeadersDict(headers.items())
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def prepare_body(self, data):
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"""Prepares the given HTTP body data."""
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self.body = data
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if self.body == b'':
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self.body = None
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if not self.body and self.method == 'GET':
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return
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if self.body is None:
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self.headers['Content-Length'] = '0'
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if isinstance(self.body, dict):
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params = list(self.body.items())
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self.body = urlencode(params, doseq=True)
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try:
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length = len(self.body)
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self.headers['Content-Length'] = str(length)
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except (AttributeError, TypeError) as e:
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pass
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if 'Content-Length' not in self.headers:
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if hasattr(data, 'seek') and hasattr(data, 'tell'):
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orig_pos = data.tell()
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data.seek(0, 2)
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end_file_pos = data.tell()
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self.headers['Content-Length'] = str(end_file_pos - orig_pos)
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data.seek(orig_pos)
|
|
|
|
if self.body and 'Content-Length' not in self.headers:
|
|
# NOTE: This should probably never happen, we don't use chunked
|
|
self.headers['Transfer-Encoding'] = 'chunked'
|
|
|
|
|
|
class AWSResponse(object):
|
|
"""
|
|
This class is originally inspired by requests.models.Response, but
|
|
has been boiled down to meet the specific use cases in botocore. This
|
|
has effectively been reduced to a named tuple for our use case. Most of
|
|
the more interesting functionality from the requests version has been
|
|
put onto our botocore.response.StreamingBody class.
|
|
"""
|
|
|
|
def __init__(self, url, status_code, headers, raw):
|
|
self.url = url
|
|
self.status_code = status_code
|
|
self.headers = HeadersDict(headers)
|
|
self.raw = raw
|
|
|
|
self._content = None
|
|
|
|
@property
|
|
def content(self):
|
|
"""Content of the response, in bytes."""
|
|
|
|
if self._content is None:
|
|
# Read the contents.
|
|
# NOTE: requests would attempt to call stream and fall back
|
|
# to a custom generator that would call read in a loop, but
|
|
# we don't rely on this behavior
|
|
self._content = bytes().join(self.raw.stream()) or bytes()
|
|
|
|
return self._content
|
|
|
|
@property
|
|
def text(self):
|
|
encoding = botocore.utils.get_encoding_from_headers(self.headers)
|
|
if encoding:
|
|
return self.content.decode(encoding)
|
|
else:
|
|
return self.content.decode('utf-8')
|
|
|
|
|
|
class _HeaderKey(object):
|
|
def __init__(self, key):
|
|
self._key = key
|
|
self._lower = key.lower()
|
|
|
|
def __hash__(self):
|
|
return hash(self._lower)
|
|
|
|
def __eq__(self, other):
|
|
return isinstance(other, _HeaderKey) and self._lower == other._lower
|
|
|
|
def __str__(self):
|
|
return self._key
|
|
|
|
def __repr__(self):
|
|
return repr(self._key)
|
|
|
|
|
|
class HeadersDict(collections.MutableMapping):
|
|
"""A case-insenseitive dictionary to represent HTTP headers. """
|
|
def __init__(self, *args, **kwargs):
|
|
self._dict = {}
|
|
self.update(*args, **kwargs)
|
|
|
|
def __setitem__(self, key, value):
|
|
self._dict[_HeaderKey(key)] = value
|
|
|
|
def __getitem__(self, key):
|
|
return self._dict[_HeaderKey(key)]
|
|
|
|
def __delitem__(self, key):
|
|
del self._dict[_HeaderKey(key)]
|
|
|
|
def __iter__(self):
|
|
return (str(key) for key in self._dict)
|
|
|
|
def __len__(self):
|
|
return len(self._dict)
|
|
|
|
def __repr__(self):
|
|
return repr(self._dict)
|
|
|
|
def copy(self):
|
|
return HeadersDict(self.items())
|