35 lines
1.0 KiB
Python
35 lines
1.0 KiB
Python
import zlib
|
|
|
|
from ..rfc7516 import JsonWebEncryption
|
|
from ..rfc7516 import JWEZipAlgorithm
|
|
|
|
GZIP_HEAD = bytes([120, 156])
|
|
MAX_SIZE = 250 * 1024
|
|
|
|
|
|
class DeflateZipAlgorithm(JWEZipAlgorithm):
|
|
name = "DEF"
|
|
description = "DEFLATE"
|
|
|
|
def compress(self, s: bytes) -> bytes:
|
|
"""Compress bytes data with DEFLATE algorithm."""
|
|
data = zlib.compress(s)
|
|
# https://datatracker.ietf.org/doc/html/rfc1951
|
|
# since DEF is always gzip, we can drop gzip headers and tail
|
|
return data[2:-4]
|
|
|
|
def decompress(self, s: bytes) -> bytes:
|
|
"""Decompress DEFLATE bytes data."""
|
|
if s.startswith(GZIP_HEAD):
|
|
decompressor = zlib.decompressobj()
|
|
else:
|
|
decompressor = zlib.decompressobj(-zlib.MAX_WBITS)
|
|
value = decompressor.decompress(s, MAX_SIZE)
|
|
if decompressor.unconsumed_tail:
|
|
raise ValueError(f"Decompressed string exceeds {MAX_SIZE} bytes")
|
|
return value
|
|
|
|
|
|
def register_jwe_rfc7518():
|
|
JsonWebEncryption.register_algorithm(DeflateZipAlgorithm())
|