mitmproxy/libmproxy/encoding.py
Aldo Cortesi ce41046786 Refine encoding support
- Push decoding down into the LRU cache
- Cope gracefully with corrupted data and incorrect encoding headers
2011-07-17 10:25:25 +12:00

49 lines
1.2 KiB
Python

"""
Utility functions for decoding response bodies.
"""
import cStringIO
import gzip, zlib
__ALL__ = ["ENCODINGS"]
ENCODINGS = set(["identity", "gzip", "deflate"])
def decode(encoding, content):
encoding_map = {
"identity": decode_identity,
"gzip": decode_gzip,
"deflate": decode_deflate,
}
return encoding_map.get(encoding, decode_identity)(content)
def decode_identity(content):
"""
Returns content unchanged. Identity is the default value of
Accept-Encoding headers.
"""
return content
def decode_gzip(content):
gfile = gzip.GzipFile(fileobj=cStringIO.StringIO(content))
try:
return gfile.read()
except IOError:
return None
def decode_deflate(content):
"""
Returns decompress data for DEFLATE. Some servers may respond with
compressed data without a zlib header or checksum. An undocumented
feature of zlib permits the lenient decompression of data missing both
values.
http://bugs.python.org/issue5784
"""
try:
try:
return zlib.decompress(content)
except zlib.error:
return zlib.decompress(content, -15)
except zlib.error:
return None