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Diffstat (limited to 'python/urllib3/response.py')
| -rw-r--r-- | python/urllib3/response.py | 705 |
1 files changed, 705 insertions, 0 deletions
diff --git a/python/urllib3/response.py b/python/urllib3/response.py new file mode 100644 index 0000000..c112690 --- /dev/null +++ b/python/urllib3/response.py @@ -0,0 +1,705 @@ +from __future__ import absolute_import +from contextlib import contextmanager +import zlib +import io +import logging +from socket import timeout as SocketTimeout +from socket import error as SocketError + +from ._collections import HTTPHeaderDict +from .exceptions import ( + BodyNotHttplibCompatible, ProtocolError, DecodeError, ReadTimeoutError, + ResponseNotChunked, IncompleteRead, InvalidHeader +) +from .packages.six import string_types as basestring, PY3 +from .packages.six.moves import http_client as httplib +from .connection import HTTPException, BaseSSLError +from .util.response import is_fp_closed, is_response_to_head + +log = logging.getLogger(__name__) + + +class DeflateDecoder(object): + + def __init__(self): + self._first_try = True + self._data = b'' + self._obj = zlib.decompressobj() + + def __getattr__(self, name): + return getattr(self._obj, name) + + def decompress(self, data): + if not data: + return data + + if not self._first_try: + return self._obj.decompress(data) + + self._data += data + try: + decompressed = self._obj.decompress(data) + if decompressed: + self._first_try = False + self._data = None + return decompressed + except zlib.error: + self._first_try = False + self._obj = zlib.decompressobj(-zlib.MAX_WBITS) + try: + return self.decompress(self._data) + finally: + self._data = None + + +class GzipDecoderState(object): + + FIRST_MEMBER = 0 + OTHER_MEMBERS = 1 + SWALLOW_DATA = 2 + + +class GzipDecoder(object): + + def __init__(self): + self._obj = zlib.decompressobj(16 + zlib.MAX_WBITS) + self._state = GzipDecoderState.FIRST_MEMBER + + def __getattr__(self, name): + return getattr(self._obj, name) + + def decompress(self, data): + ret = bytearray() + if self._state == GzipDecoderState.SWALLOW_DATA or not data: + return bytes(ret) + while True: + try: + ret += self._obj.decompress(data) + except zlib.error: + previous_state = self._state + # Ignore data after the first error + self._state = GzipDecoderState.SWALLOW_DATA + if previous_state == GzipDecoderState.OTHER_MEMBERS: + # Allow trailing garbage acceptable in other gzip clients + return bytes(ret) + raise + data = self._obj.unused_data + if not data: + return bytes(ret) + self._state = GzipDecoderState.OTHER_MEMBERS + self._obj = zlib.decompressobj(16 + zlib.MAX_WBITS) + + +class MultiDecoder(object): + """ + From RFC7231: + If one or more encodings have been applied to a representation, the + sender that applied the encodings MUST generate a Content-Encoding + header field that lists the content codings in the order in which + they were applied. + """ + + def __init__(self, modes): + self._decoders = [_get_decoder(m.strip()) for m in modes.split(',')] + + def flush(self): + return self._decoders[0].flush() + + def decompress(self, data): + for d in reversed(self._decoders): + data = d.decompress(data) + return data + + +def _get_decoder(mode): + if ',' in mode: + return MultiDecoder(mode) + + if mode == 'gzip': + return GzipDecoder() + + 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. This + class is also compatible with the Python standard library's :mod:`io` + module, and can hence be treated as a readable object in the context of that + framework. + + 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, will attempt to decode the body based on the + 'content-encoding' header. + + :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. + + :param retries: + The retries contains the last :class:`~urllib3.util.retry.Retry` that + was used during the request. + + :param enforce_content_length: + Enforce content length checking. Body returned by server must match + value of Content-Length header, if present. Otherwise, raise error. + """ + + 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, msg=None, + retries=None, enforce_content_length=False, + request_method=None, request_url=None): + + if isinstance(headers, HTTPHeaderDict): + self.headers = headers + else: + self.headers = HTTPHeaderDict(headers) + self.status = status + self.version = version + self.reason = reason + self.strict = strict + self.decode_content = decode_content + self.retries = retries + self.enforce_content_length = enforce_content_length + + self._decoder = None + self._body = None + self._fp = None + self._original_response = original_response + self._fp_bytes_read = 0 + self.msg = msg + self._request_url = request_url + + if body and isinstance(body, (basestring, bytes)): + self._body = body + + self._pool = pool + self._connection = connection + + if hasattr(body, 'read'): + self._fp = body + + # Are we using the chunked-style of transfer encoding? + self.chunked = False + self.chunk_left = None + tr_enc = self.headers.get('transfer-encoding', '').lower() + # Don't incur the penalty of creating a list and then discarding it + encodings = (enc.strip() for enc in tr_enc.split(",")) + if "chunked" in encodings: + self.chunked = True + + # Determine length of response + self.length_remaining = self._init_length(request_method) + + # If requested, preload the 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) + + @property + def connection(self): + return self._connection + + def isclosed(self): + return is_fp_closed(self._fp) + + 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 _init_length(self, request_method): + """ + Set initial length value for Response content if available. + """ + length = self.headers.get('content-length') + + if length is not None: + if self.chunked: + # This Response will fail with an IncompleteRead if it can't be + # received as chunked. This method falls back to attempt reading + # the response before raising an exception. + log.warning("Received response with both Content-Length and " + "Transfer-Encoding set. This is expressly forbidden " + "by RFC 7230 sec 3.3.2. Ignoring Content-Length and " + "attempting to process response as Transfer-Encoding: " + "chunked.") + return None + + try: + # RFC 7230 section 3.3.2 specifies multiple content lengths can + # be sent in a single Content-Length header + # (e.g. Content-Length: 42, 42). This line ensures the values + # are all valid ints and that as long as the `set` length is 1, + # all values are the same. Otherwise, the header is invalid. + lengths = set([int(val) for val in length.split(',')]) + if len(lengths) > 1: + raise InvalidHeader("Content-Length contained multiple " + "unmatching values (%s)" % length) + length = lengths.pop() + except ValueError: + length = None + else: + if length < 0: + length = None + + # Convert status to int for comparison + # In some cases, httplib returns a status of "_UNKNOWN" + try: + status = int(self.status) + except ValueError: + status = 0 + + # Check for responses that shouldn't include a body + if status in (204, 304) or 100 <= status < 200 or request_method == 'HEAD': + length = 0 + + return length + + def _init_decoder(self): + """ + Set-up the _decoder attribute if necessary. + """ + # Note: content-encoding value should be case-insensitive, per RFC 7230 + # Section 3.2 + 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) + elif ',' in content_encoding: + encodings = [e.strip() for e in content_encoding.split(',') if e.strip() in self.CONTENT_DECODERS] + if len(encodings): + self._decoder = _get_decoder(content_encoding) + + def _decode(self, data, decode_content, flush_decoder): + """ + Decode the data passed in and potentially flush the decoder. + """ + try: + if decode_content and self._decoder: + data = self._decoder.decompress(data) + except (IOError, zlib.error) as e: + content_encoding = self.headers.get('content-encoding', '').lower() + raise DecodeError( + "Received response with content-encoding: %s, but " + "failed to decode it." % content_encoding, e) + + if flush_decoder and decode_content: + data += self._flush_decoder() + + return data + + def _flush_decoder(self): + """ + Flushes the decoder. Should only be called if the decoder is actually + being used. + """ + if self._decoder: + buf = self._decoder.decompress(b'') + return buf + self._decoder.flush() + + return b'' + + @contextmanager + def _error_catcher(self): + """ + Catch low-level python exceptions, instead re-raising urllib3 + variants, so that low-level exceptions are not leaked in the + high-level api. + + On exit, release the connection back to the pool. + """ + clean_exit = False + + try: + try: + yield + + except SocketTimeout: + # FIXME: Ideally we'd like to include the url in the ReadTimeoutError but + # there is yet no clean way to get at it from this context. + raise ReadTimeoutError(self._pool, None, 'Read timed out.') + + except BaseSSLError as e: + # FIXME: Is there a better way to differentiate between SSLErrors? + if 'read operation timed out' not in str(e): # Defensive: + # This shouldn't happen but just in case we're missing an edge + # case, let's avoid swallowing SSL errors. + raise + + raise ReadTimeoutError(self._pool, None, 'Read timed out.') + + except (HTTPException, SocketError) as e: + # This includes IncompleteRead. + raise ProtocolError('Connection broken: %r' % e, e) + + # If no exception is thrown, we should avoid cleaning up + # unnecessarily. + clean_exit = True + finally: + # If we didn't terminate cleanly, we need to throw away our + # connection. + if not clean_exit: + # The response may not be closed but we're not going to use it + # anymore so close it now to ensure that the connection is + # released back to the pool. + if self._original_response: + self._original_response.close() + + # Closing the response may not actually be sufficient to close + # everything, so if we have a hold of the connection close that + # too. + if self._connection: + self._connection.close() + + # If we hold the original response but it's closed now, we should + # return the connection back to the pool. + if self._original_response and self._original_response.isclosed(): + self.release_conn() + + 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.) + """ + self._init_decoder() + if decode_content is None: + decode_content = self.decode_content + + if self._fp is None: + return + + flush_decoder = False + data = None + + with self._error_catcher(): + 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 + if self.enforce_content_length and self.length_remaining not in (0, None): + # This is an edge case that httplib failed to cover due + # to concerns of backward compatibility. We're + # addressing it here to make sure IncompleteRead is + # raised during streaming, so all calls with incorrect + # Content-Length are caught. + raise IncompleteRead(self._fp_bytes_read, self.length_remaining) + + if data: + self._fp_bytes_read += len(data) + if self.length_remaining is not None: + self.length_remaining -= len(data) + + data = self._decode(data, decode_content, flush_decoder) + + if cache_content: + self._body = data + + return data + + 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. + """ + if self.chunked and self.supports_chunked_reads(): + for line in self.read_chunked(amt, decode_content=decode_content): + yield line + else: + 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 = r.msg + + if not isinstance(headers, HTTPHeaderDict): + if PY3: # Python 3 + headers = HTTPHeaderDict(headers.items()) + else: # Python 2 + headers = HTTPHeaderDict.from_httplib(headers) + + # HTTPResponse objects in Python 3 don't have a .strict attribute + strict = getattr(r, 'strict', 0) + resp = ResponseCls(body=r, + headers=headers, + status=r.status, + version=r.version, + reason=r.reason, + strict=strict, + original_response=r, + **response_kw) + return resp + + # Backwards-compatibility methods for httplib.HTTPResponse + def getheaders(self): + return self.headers + + def getheader(self, name, default=None): + return self.headers.get(name, default) + + # Backwards compatibility for http.cookiejar + def info(self): + return self.headers + + # Overrides from io.IOBase + def close(self): + if not self.closed: + self._fp.close() + + if self._connection: + self._connection.close() + + @property + def closed(self): + if self._fp is None: + return True + elif hasattr(self._fp, 'isclosed'): + return self._fp.isclosed() + elif hasattr(self._fp, 'closed'): + return self._fp.closed + 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): + # This method is required for `io` module compatibility. + return True + + def readinto(self, b): + # This method is required for `io` module compatibility. + temp = self.read(len(b)) + if len(temp) == 0: + return 0 + else: + b[:len(temp)] = temp + return len(temp) + + def supports_chunked_reads(self): + """ + Checks if the underlying file-like object looks like a + httplib.HTTPResponse object. We do this by testing for the fp + attribute. If it is present we assume it returns raw chunks as + processed by read_chunked(). + """ + return hasattr(self._fp, 'fp') + + def _update_chunk_length(self): + # First, we'll figure out length of a chunk and then + # we'll try to read it from socket. + if self.chunk_left is not None: + return + line = self._fp.fp.readline() + line = line.split(b';', 1)[0] + try: + self.chunk_left = int(line, 16) + except ValueError: + # Invalid chunked protocol response, abort. + self.close() + raise httplib.IncompleteRead(line) + + def _handle_chunk(self, amt): + returned_chunk = None + if amt is None: + chunk = self._fp._safe_read(self.chunk_left) + returned_chunk = chunk + self._fp._safe_read(2) # Toss the CRLF at the end of the chunk. + self.chunk_left = None + elif amt < self.chunk_left: + value = self._fp._safe_read(amt) + self.chunk_left = self.chunk_left - amt + returned_chunk = value + elif amt == self.chunk_left: + value = self._fp._safe_read(amt) + self._fp._safe_read(2) # Toss the CRLF at the end of the chunk. + self.chunk_left = None + returned_chunk = value + else: # amt > self.chunk_left + returned_chunk = self._fp._safe_read(self.chunk_left) + self._fp._safe_read(2) # Toss the CRLF at the end of the chunk. + self.chunk_left = None + return returned_chunk + + def read_chunked(self, amt=None, decode_content=None): + """ + Similar to :meth:`HTTPResponse.read`, but with an additional + parameter: ``decode_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. + """ + self._init_decoder() + # FIXME: Rewrite this method and make it a class with a better structured logic. + if not self.chunked: + raise ResponseNotChunked( + "Response is not chunked. " + "Header 'transfer-encoding: chunked' is missing.") + if not self.supports_chunked_reads(): + raise BodyNotHttplibCompatible( + "Body should be httplib.HTTPResponse like. " + "It should have have an fp attribute which returns raw chunks.") + + with self._error_catcher(): + # Don't bother reading the body of a HEAD request. + if self._original_response and is_response_to_head(self._original_response): + self._original_response.close() + return + + # If a response is already read and closed + # then return immediately. + if self._fp.fp is None: + return + + while True: + self._update_chunk_length() + if self.chunk_left == 0: + break + chunk = self._handle_chunk(amt) + decoded = self._decode(chunk, decode_content=decode_content, + flush_decoder=False) + if decoded: + yield decoded + + if decode_content: + # On CPython and PyPy, we should never need to flush the + # decoder. However, on Jython we *might* need to, so + # lets defensively do it anyway. + decoded = self._flush_decoder() + if decoded: # Platform-specific: Jython. + yield decoded + + # Chunk content ends with \r\n: discard it. + while True: + line = self._fp.fp.readline() + if not line: + # Some sites may not end with '\r\n'. + break + if line == b'\r\n': + break + + # We read everything; close the "file". + if self._original_response: + self._original_response.close() + + def geturl(self): + """ + Returns the URL that was the source of this response. + If the request that generated this response redirected, this method + will return the final redirect location. + """ + if self.retries is not None and len(self.retries.history): + return self.retries.history[-1].redirect_location + else: + return self._request_url |