node pako.gizp() with python gzip issue

Question

I was restoring the Node pako gzip method using Python and encountered the following problem:

node：

const pako = require('pako');
const test = 'aaa'
var data = pako.gzip(test);
console.log(data)
Uint8Array(23) [
   31, 139,   8,  0,  0, 0, 0,  0,
    0,   3,  75, 76, 76, 4, 0, 45,
  115,   7, 240,  3,  0, 0, 0
]

python：

import numpy
import gzip
test = 'aaa'
compressed_byte_pako = gzip.compress(test.encode('utf-8'))
compressed = numpy.frombuffer(compressed_byte_pako,  dtype=numpy.uint8)
print(compressed)
[ 31 139   8   0 178  45  89  98   2 255  75  76  76   4   0  45 115   7
 240   3   0   0   0]

Why do they compress inconsistently?

score 0 · Accepted Answer · answered Apr 16 '22 at 02:03

0

Though there is no guarantee that they will, they are compressing identically. The compressed portions and trailer with checks on the uncompressed data are the last 13 bytes of each, and are the same. Both will decompress to the original data ('aaa').

The first ten bytes are the gzip headers. The first one has no time stamp, compression level, or operating system information. The second one does.

answered Apr 16 '22 at 02:03

Mark Adler

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Can you write a demo?Thank you very much – user11816956 Apr 16 '22 at 05:36
I want Python to be the same as Node pako.gzip. How does this work? – user11816956 Apr 16 '22 at 06:01
There is no need to make them identical. All that matters is that they both decompress exactly to the original data, which they do. – Mark Adler Apr 16 '22 at 14:50

node pako.gizp() with python gzip issue

1 Answers1