313 lines
10 KiB
Python
313 lines
10 KiB
Python
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# urllib3/response.py
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# Copyright 2008-2013 Andrey Petrov and contributors (see CONTRIBUTORS.txt)
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#
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# This module is part of urllib3 and is released under
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# the MIT License: http://www.opensource.org/licenses/mit-license.php
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import logging
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import zlib
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import io
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from .exceptions import DecodeError
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from .packages.six import string_types as basestring, binary_type
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from .util import is_fp_closed
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log = logging.getLogger(__name__)
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class DeflateDecoder(object):
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def __init__(self):
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self._first_try = True
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self._data = binary_type()
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self._obj = zlib.decompressobj()
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def __getattr__(self, name):
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return getattr(self._obj, name)
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def decompress(self, data):
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if not self._first_try:
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return self._obj.decompress(data)
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self._data += data
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try:
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return self._obj.decompress(data)
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except zlib.error:
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self._first_try = False
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self._obj = zlib.decompressobj(-zlib.MAX_WBITS)
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try:
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return self.decompress(self._data)
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finally:
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self._data = None
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def _get_decoder(mode):
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if mode == 'gzip':
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return zlib.decompressobj(16 + zlib.MAX_WBITS)
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return DeflateDecoder()
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class HTTPResponse(io.IOBase):
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"""
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HTTP Response container.
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Backwards-compatible to httplib's HTTPResponse but the response ``body`` is
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loaded and decoded on-demand when the ``data`` property is accessed.
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Extra parameters for behaviour not present in httplib.HTTPResponse:
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:param preload_content:
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If True, the response's body will be preloaded during construction.
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:param decode_content:
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If True, attempts to decode specific content-encoding's based on headers
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(like 'gzip' and 'deflate') will be skipped and raw data will be used
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instead.
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:param original_response:
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When this HTTPResponse wrapper is generated from an httplib.HTTPResponse
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object, it's convenient to include the original for debug purposes. It's
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otherwise unused.
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"""
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CONTENT_DECODERS = ['gzip', 'deflate']
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REDIRECT_STATUSES = [301, 302, 303, 307, 308]
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def __init__(self, body='', headers=None, status=0, version=0, reason=None,
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strict=0, preload_content=True, decode_content=True,
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original_response=None, pool=None, connection=None):
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self.headers = headers or {}
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self.status = status
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self.version = version
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self.reason = reason
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self.strict = strict
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self.decode_content = decode_content
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self._decoder = None
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self._body = body if body and isinstance(body, basestring) else None
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self._fp = None
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self._original_response = original_response
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self._fp_bytes_read = 0
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self._pool = pool
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self._connection = connection
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if hasattr(body, 'read'):
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self._fp = body
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if preload_content and not self._body:
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self._body = self.read(decode_content=decode_content)
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def get_redirect_location(self):
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"""
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Should we redirect and where to?
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:returns: Truthy redirect location string if we got a redirect status
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code and valid location. ``None`` if redirect status and no
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location. ``False`` if not a redirect status code.
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"""
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if self.status in self.REDIRECT_STATUSES:
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return self.headers.get('location')
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return False
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def release_conn(self):
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if not self._pool or not self._connection:
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return
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self._pool._put_conn(self._connection)
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self._connection = None
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@property
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def data(self):
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# For backwords-compat with earlier urllib3 0.4 and earlier.
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if self._body:
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return self._body
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if self._fp:
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return self.read(cache_content=True)
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def tell(self):
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"""
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Obtain the number of bytes pulled over the wire so far. May differ from
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the amount of content returned by :meth:``HTTPResponse.read`` if bytes
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are encoded on the wire (e.g, compressed).
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"""
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return self._fp_bytes_read
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def read(self, amt=None, decode_content=None, cache_content=False):
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"""
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Similar to :meth:`httplib.HTTPResponse.read`, but with two additional
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parameters: ``decode_content`` and ``cache_content``.
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:param amt:
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How much of the content to read. If specified, caching is skipped
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because it doesn't make sense to cache partial content as the full
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response.
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:param decode_content:
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If True, will attempt to decode the body based on the
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'content-encoding' header.
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:param cache_content:
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If True, will save the returned data such that the same result is
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returned despite of the state of the underlying file object. This
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is useful if you want the ``.data`` property to continue working
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after having ``.read()`` the file object. (Overridden if ``amt`` is
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set.)
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"""
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# Note: content-encoding value should be case-insensitive, per RFC 2616
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# Section 3.5
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content_encoding = self.headers.get('content-encoding', '').lower()
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if self._decoder is None:
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if content_encoding in self.CONTENT_DECODERS:
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self._decoder = _get_decoder(content_encoding)
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if decode_content is None:
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decode_content = self.decode_content
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if self._fp is None:
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return
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flush_decoder = False
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try:
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if amt is None:
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# cStringIO doesn't like amt=None
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data = self._fp.read()
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flush_decoder = True
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else:
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cache_content = False
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data = self._fp.read(amt)
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if amt != 0 and not data: # Platform-specific: Buggy versions of Python.
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# Close the connection when no data is returned
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#
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# This is redundant to what httplib/http.client _should_
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# already do. However, versions of python released before
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# December 15, 2012 (http://bugs.python.org/issue16298) do not
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# properly close the connection in all cases. There is no harm
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# in redundantly calling close.
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self._fp.close()
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flush_decoder = True
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self._fp_bytes_read += len(data)
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try:
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if decode_content and self._decoder:
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data = self._decoder.decompress(data)
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except (IOError, zlib.error) as e:
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raise DecodeError(
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"Received response with content-encoding: %s, but "
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"failed to decode it." % content_encoding,
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e)
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if flush_decoder and decode_content and self._decoder:
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buf = self._decoder.decompress(binary_type())
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data += buf + self._decoder.flush()
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if cache_content:
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self._body = data
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return data
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finally:
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if self._original_response and self._original_response.isclosed():
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self.release_conn()
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def stream(self, amt=2**16, decode_content=None):
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"""
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A generator wrapper for the read() method. A call will block until
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``amt`` bytes have been read from the connection or until the
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connection is closed.
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:param amt:
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How much of the content to read. The generator will return up to
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much data per iteration, but may return less. This is particularly
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likely when using compressed data. However, the empty string will
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never be returned.
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:param decode_content:
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If True, will attempt to decode the body based on the
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'content-encoding' header.
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"""
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while not is_fp_closed(self._fp):
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data = self.read(amt=amt, decode_content=decode_content)
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if data:
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yield data
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@classmethod
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def from_httplib(ResponseCls, r, **response_kw):
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"""
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Given an :class:`httplib.HTTPResponse` instance ``r``, return a
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corresponding :class:`urllib3.response.HTTPResponse` object.
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Remaining parameters are passed to the HTTPResponse constructor, along
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with ``original_response=r``.
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"""
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# Normalize headers between different versions of Python
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headers = {}
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for k, v in r.getheaders():
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# Python 3: Header keys are returned capitalised
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k = k.lower()
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has_value = headers.get(k)
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if has_value: # Python 3: Repeating header keys are unmerged.
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v = ', '.join([has_value, v])
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headers[k] = v
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# HTTPResponse objects in Python 3 don't have a .strict attribute
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strict = getattr(r, 'strict', 0)
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return ResponseCls(body=r,
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headers=headers,
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status=r.status,
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version=r.version,
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reason=r.reason,
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strict=strict,
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original_response=r,
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**response_kw)
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# Backwards-compatibility methods for httplib.HTTPResponse
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def getheaders(self):
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return self.headers
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def getheader(self, name, default=None):
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return self.headers.get(name, default)
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# Overrides from io.IOBase
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def close(self):
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if not self.closed:
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self._fp.close()
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@property
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def closed(self):
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if self._fp is None:
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return True
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elif hasattr(self._fp, 'closed'):
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return self._fp.closed
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elif hasattr(self._fp, 'isclosed'): # Python 2
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return self._fp.isclosed()
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else:
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return True
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def fileno(self):
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if self._fp is None:
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raise IOError("HTTPResponse has no file to get a fileno from")
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elif hasattr(self._fp, "fileno"):
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return self._fp.fileno()
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else:
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raise IOError("The file-like object this HTTPResponse is wrapped "
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"around has no file descriptor")
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def flush(self):
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if self._fp is not None and hasattr(self._fp, 'flush'):
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return self._fp.flush()
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def readable(self):
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return True
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