File size: 30,641 Bytes
0c87db7
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
from __future__ import absolute_import

import io
import logging
import sys
import warnings
import zlib
from contextlib import contextmanager
from socket import error as SocketError
from socket import timeout as SocketTimeout

brotli = None

from . import util
from ._collections import HTTPHeaderDict
from .connection import BaseSSLError, HTTPException
from .exceptions import (
    BodyNotHttplibCompatible,
    DecodeError,
    HTTPError,
    IncompleteRead,
    InvalidChunkLength,
    InvalidHeader,
    ProtocolError,
    ReadTimeoutError,
    ResponseNotChunked,
    SSLError,
)
from .packages import six
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)


if brotli is not None:

    class BrotliDecoder(object):
        # Supports both 'brotlipy' and 'Brotli' packages
        # since they share an import name. The top branches
        # are for 'brotlipy' and bottom branches for 'Brotli'
        def __init__(self):
            self._obj = brotli.Decompressor()
            if hasattr(self._obj, "decompress"):
                self.decompress = self._obj.decompress
            else:
                self.decompress = self._obj.process

        def flush(self):
            if hasattr(self._obj, "flush"):
                return self._obj.flush()
            return b""


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()

    if brotli is not None and mode == "br":
        return BrotliDecoder()

    return DeflateDecoder()


class HTTPResponse(io.IOBase):
    """
    HTTP Response container.

    Backwards-compatible with :class:`http.client.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 :class:`http.client.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 :class:`http.client.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"]
    if brotli is not None:
        CONTENT_DECODERS += ["br"]
    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,
        auto_close=True,
    ):

        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.auto_close = auto_close

        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, (six.string_types, 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

    def drain_conn(self):
        """
        Read and discard any remaining HTTP response data in the response connection.

        Unread data in the HTTPResponse connection blocks the connection from being released back to the pool.
        """
        try:
            self.read()
        except (HTTPError, SocketError, BaseSSLError, HTTPException):
            pass

    @property
    def data(self):
        # For backwards-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:``urllib3.response.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)

    DECODER_ERROR_CLASSES = (IOError, zlib.error)
    if brotli is not None:
        DECODER_ERROR_CLASSES += (brotli.error,)

    def _decode(self, data, decode_content, flush_decoder):
        """
        Decode the data passed in and potentially flush the decoder.
        """
        if not decode_content:
            return data

        try:
            if self._decoder:
                data = self._decoder.decompress(data)
        except self.DECODER_ERROR_CLASSES 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:
            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):
                    # SSL errors related to framing/MAC get wrapped and reraised here
                    raise SSLError(e)

                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 _fp_read(self, amt):
        """
        Read a response with the thought that reading the number of bytes
        larger than can fit in a 32-bit int at a time via SSL in some
        known cases leads to an overflow error that has to be prevented
        if `amt` or `self.length_remaining` indicate that a problem may
        happen.

        The known cases:
          * 3.8 <= CPython < 3.9.7 because of a bug
            https://github.com/urllib3/urllib3/issues/2513#issuecomment-1152559900.
          * urllib3 injected with pyOpenSSL-backed SSL-support.
          * CPython < 3.10 only when `amt` does not fit 32-bit int.
        """
        assert self._fp
        c_int_max = 2 ** 31 - 1
        if (
            (
                (amt and amt > c_int_max)
                or (self.length_remaining and self.length_remaining > c_int_max)
            )
            and not util.IS_SECURETRANSPORT
            and (util.IS_PYOPENSSL or sys.version_info < (3, 10))
        ):
            buffer = io.BytesIO()
            # Besides `max_chunk_amt` being a maximum chunk size, it
            # affects memory overhead of reading a response by this
            # method in CPython.
            # `c_int_max` equal to 2 GiB - 1 byte is the actual maximum
            # chunk size that does not lead to an overflow error, but
            # 256 MiB is a compromise.
            max_chunk_amt = 2 ** 28
            while amt is None or amt != 0:
                if amt is not None:
                    chunk_amt = min(amt, max_chunk_amt)
                    amt -= chunk_amt
                else:
                    chunk_amt = max_chunk_amt
                data = self._fp.read(chunk_amt)
                if not data:
                    break
                buffer.write(data)
                del data  # to reduce peak memory usage by `max_chunk_amt`.
            return buffer.getvalue()
        else:
            # StringIO doesn't like amt=None
            return self._fp.read(amt) if amt is not None else self._fp.read()

    def read(self, amt=None, decode_content=None, cache_content=False):
        """
        Similar to :meth:`http.client.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
        fp_closed = getattr(self._fp, "closed", False)

        with self._error_catcher():
            data = self._fp_read(amt) if not fp_closed else b""
            if amt is None:
                flush_decoder = True
            else:
                cache_content = False
                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:`http.client.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 six.PY2:
                # Python 2.7
                headers = HTTPHeaderDict.from_httplib(headers)
            else:
                headers = HTTPHeaderDict(headers.items())

        # 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 http.client.HTTPResponse
    def getheaders(self):
        warnings.warn(
            "HTTPResponse.getheaders() is deprecated and will be removed "
            "in urllib3 v2.1.0. Instead access HTTPResponse.headers directly.",
            category=DeprecationWarning,
            stacklevel=2,
        )
        return self.headers

    def getheader(self, name, default=None):
        warnings.warn(
            "HTTPResponse.getheader() is deprecated and will be removed "
            "in urllib3 v2.1.0. Instead use HTTPResponse.headers.get(name, default).",
            category=DeprecationWarning,
            stacklevel=2,
        )
        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()

        if not self.auto_close:
            io.IOBase.close(self)

    @property
    def closed(self):
        if not self.auto_close:
            return io.IOBase.closed.__get__(self)
        elif 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")
            and not getattr(self._fp, "closed", False)
        ):
            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
        :class:`http.client.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 InvalidChunkLength(self, 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 http.client.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

    def __iter__(self):
        buffer = []
        for chunk in self.stream(decode_content=True):
            if b"\n" in chunk:
                chunk = chunk.split(b"\n")
                yield b"".join(buffer) + chunk[0] + b"\n"
                for x in chunk[1:-1]:
                    yield x + b"\n"
                if chunk[-1]:
                    buffer = [chunk[-1]]
                else:
                    buffer = []
            else:
                buffer.append(chunk)
        if buffer:
            yield b"".join(buffer)