how to read content from a compressed zip file?

[xlla]

I am using this zipfile lib to read zip file content.

it can work with plain/non-compressed zip file.

import zipfile
import io

buffer = b'PK\x03\x04\n\x00\x00\x00\x00\x00\n\\\x88Gzzo\xed\x03\x00\x00\x00\x03\x00\x00\x00\x07\x00\x1c\x00foo.txtUT\t\x00\x03$\x14gV(\x14gVux\x0b\x00\x01\x041\x04\x00\x00\x041\x04\x00\x00hi\nPK\x01\x02\x1e\x03\n\x00\x00\x00\x00\x00\n\\\x88Gzzo\xed\x03\x00\x00\x00\x03\x00\x00\x00\x07\x00\x18\x00\x00\x00\x00\x00\x01\x00\x00\x00\xb4\x81\x00\x00\x00\x00foo.txtUT\x05\x00\x03$\x14gVux\x0b\x00\x01\x041\x04\x00\x00\x041\x04\x00\x00PK\x05\x06\x00\x00\x00\x00\x01\x00\x01\x00M\x00\x00\x00D\x00\x00\x00\x00\x00'

z = zipfile.ZipFile(io.BytesIO(buffer))

# The following three lines are alternatives. Use one of them
# according to your need:
foo = z.read('foo.txt')        # Reads the data from "foo.txt"
z.close()

print(foo)
b'hi\n'

I can observe the zip file info:

for info in z.infolist():
    print(info.filename)
    print('\tSystem:\t\t' + str(info.create_system) + '(0 = Windows, 3 = Unix)')
    print('\tZIP version:\t' + str(info.create_version))
    print('\tCompressed:\t' + str(info.compress_size) + ' bytes')
    print('\tUncompressed:\t' + str(info.file_size) + ' bytes')

foo.txt
	System:		3(0 = Windows, 3 = Unix)
	ZIP version:	30
	Compressed:	3 bytes
	Uncompressed:	3 bytes

I think it is not compressed since Compressed equal to Uncompressed.

for another example,

buffer=b'PK\x03\x04\x14\x00\x00\x00\x08\x00Bw\x18W\xe0\x968\x86N\x00\x00\x00[\x00\x00\x00\x08\x00\x1c\x00text.txtUT\t\x00\x03\xeca\xe7d\xeca\xe7dux\x0b\x00\x01\x04\xe8\x03\x00\x00\x04\xe8\x03\x00\x00\x1d\xcb\xcb\x11\x80 \x10\x04\xd1;QL\x04\x86b\x0e[\xb2(\x160\x14\xe0\x07\xa3\x17\xbd\xf5\xe1\xf5\xcc\x0b\xbe\xa2m\x8a\xe6\xa3\xc2\xb1@B\xc0JZDMh\xc4~\xc4\x0c\x9eZL\x90\xa7\x0frk\x85$\x8b\x85\xe3\x18\xe0\xbb\xc5[\xd0\xfd\x99\xa5\xb4>\x99\x17PK\x01\x02\x1e\x03\x14\x00\x00\x00\x08\x00Bw\x18W\xe0\x968\x86N\x00\x00\x00[\x00\x00\x00\x08\x00\x18\x00\x00\x00\x00\x00\x01\x00\x00\x00\xa4\x81\x00\x00\x00\x00text.txtUT\x05\x00\x03\xeca\xe7dux\x0b\x00\x01\x04\xe8\x03\x00\x00\x04\xe8\x03\x00\x00PK\x05\x06\x00\x00\x00\x00\x01\x00\x01\x00N\x00\x00\x00\x90\x00\x00\x00\x00\x00'

it will print

text.txt
	System:		3(0 = Windows, 3 = Unix)
	ZIP version:	30
	Compressed:	78 bytes
	Uncompressed:	91 bytes

but failure to read content

>>> foo = z.read('text.txt')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/lib/zipfile.py", line 1715, in read
  File "/lib/zipfile.py", line 1113, in read
  File "/lib/zipfile.py", line 1217, in _read1
  File "/lib/zipfile.py", line 1145, in _update_crc
BadZipFile: Bad CRC-32 for file 'text.txt'

the same code work on full python version.

print(foo)
b'Now is the time for all good men to jump over\nlazy foxes and come to the aid of the party.\n'

and I'v found the micropython version zipfile use deflate to handle the underlay data.

the deflate.DeflateIO failure to decompress zlib version data.

[xlla]

Sorry, I'v found it's a bug related to zipfile, so it should not be discussed here.