netdata/python.d/python_modules/urllib3/response.py at master · ed00m/netdata · GitHub

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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, binary_type, 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 = binary_type()

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 GzipDecoder(object):

def __init__(self):

self._obj = zlib.decompressobj(16 + zlib.MAX_WBITS)

def __getattr__(self, name):

return getattr(self._obj, name)

def decompress(self, data):

if not data:

return data

return self._obj.decompress(data)

def _get_decoder(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, 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.

: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,

retries=None, enforce_content_length=False, request_method=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

if body and isinstance(body, (basestring, binary_type)):

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 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 and 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

elif length is not 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 and content_encoding in self.CONTENT_DECODERS:

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:

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)

# 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 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.")

# 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

with self._error_catcher():

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()

netdata/python.d/python_modules/urllib3/response.py at master · ed00m/netdata · GitHub

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