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-rw-r--r--cherrypy/lib/encoding.py24
1 files changed, 22 insertions, 2 deletions
diff --git a/cherrypy/lib/encoding.py b/cherrypy/lib/encoding.py
index 54a7a8a8..c2c478a5 100644
--- a/cherrypy/lib/encoding.py
+++ b/cherrypy/lib/encoding.py
@@ -9,6 +9,10 @@ from cherrypy.lib import is_closable_iterator
from cherrypy.lib import set_vary_header
+_COMPRESSION_LEVEL_FAST = 1
+_COMPRESSION_LEVEL_BEST = 9
+
+
def decode(encoding=None, default_encoding='utf-8'):
"""Replace or extend the list of charsets used to decode a request entity.
@@ -285,13 +289,29 @@ def compress(body, compress_level):
"""Compress 'body' at the given compress_level."""
import zlib
- # See http://www.gzip.org/zlib/rfc-gzip.html
+ # See https://tools.ietf.org/html/rfc1952
yield b'\x1f\x8b' # ID1 and ID2: gzip marker
yield b'\x08' # CM: compression method
yield b'\x00' # FLG: none set
# MTIME: 4 bytes
yield struct.pack('<L', int(time.time()) & int('FFFFFFFF', 16))
- yield b'\x02' # XFL: max compression, slowest algo
+
+ # RFC 1952, section 2.3.1:
+ #
+ # XFL (eXtra FLags)
+ # These flags are available for use by specific compression
+ # methods. The "deflate" method (CM = 8) sets these flags as
+ # follows:
+ #
+ # XFL = 2 - compressor used maximum compression,
+ # slowest algorithm
+ # XFL = 4 - compressor used fastest algorithm
+ if compress_level == _COMPRESSION_LEVEL_BEST:
+ yield b'\x02' # XFL: max compression, slowest algo
+ elif compress_level == _COMPRESSION_LEVEL_FAST:
+ yield b'\x04' # XFL: min compression, fastest algo
+ else:
+ yield b'\x00' # XFL: compression unset/tradeoff
yield b'\xff' # OS: unknown
crc = zlib.crc32(b'')