88 lines
1.9 KiB
Python
88 lines
1.9 KiB
Python
"""
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Utility functions for decoding response bodies.
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"""
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from __future__ import absolute_import
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from io import BytesIO
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import gzip
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import zlib
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ENCODINGS = {"identity", "gzip", "deflate"}
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def decode(e, content):
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if not isinstance(content, bytes):
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return None
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encoding_map = {
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"identity": identity,
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"gzip": decode_gzip,
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"deflate": decode_deflate,
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}
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if e not in encoding_map:
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return None
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return encoding_map[e](content)
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def encode(e, content):
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if not isinstance(content, bytes):
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return None
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encoding_map = {
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"identity": identity,
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"gzip": encode_gzip,
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"deflate": encode_deflate,
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}
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if e not in encoding_map:
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return None
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return encoding_map[e](content)
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def identity(content):
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"""
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Returns content unchanged. Identity is the default value of
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Accept-Encoding headers.
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"""
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return content
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def decode_gzip(content):
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gfile = gzip.GzipFile(fileobj=BytesIO(content))
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try:
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return gfile.read()
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except (IOError, EOFError):
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return None
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def encode_gzip(content):
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s = BytesIO()
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gf = gzip.GzipFile(fileobj=s, mode='wb')
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gf.write(content)
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gf.close()
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return s.getvalue()
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def decode_deflate(content):
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"""
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Returns decompressed data for DEFLATE. Some servers may respond with
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compressed data without a zlib header or checksum. An undocumented
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feature of zlib permits the lenient decompression of data missing both
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values.
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http://bugs.python.org/issue5784
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"""
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try:
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try:
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return zlib.decompress(content)
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except zlib.error:
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return zlib.decompress(content, -15)
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except zlib.error:
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return None
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def encode_deflate(content):
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"""
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Returns compressed content, always including zlib header and checksum.
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"""
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return zlib.compress(content)
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__all__ = ["ENCODINGS", "encode", "decode"]
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