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편집 파일: response.py

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