Python exception: error Bad compression level-CodePudding

So I am trying to write a program that encodes(and decodes) a string with this formula:

Decode: b64 decode -> zlib decode -> decoded string

Here is how i coded it:

def decode_level(level_data: str) -> str:
    base64_decoded = base64.urlsafe_b64decode(level_data.encode())
    decompressed = zlib.decompress(base64_decoded, 15 | 32)
    return decompressed.decode()

But how do I reverse it? I mean how do I encode that string? I have tried this:

def encodeLevelData(lvlData: str) -> str:
    eData = lvlData.encode() # eData -> encoded data
    compressed = zlib.compress(eData, 15 | 32)
    b64decoded = base64.urlsafe_b64encode(compressed)
    return b64decoded

But it gives me an error on this line:

-> Exception has occurred: Bad compression: levelcompressed = zlib.compress(eData, 15 | 32)

Why does this error happen? And how do I fix it? Here is the string that im trying to encode: https://pastebin.com/4Dkz07yY

CodePudding user response：

It says the level is bad because the level is bad. You should have just gone to the documentation to see that the level for zlib.compress() can only be in -1..9.

It looks like you trying to give a wbits value to the level parameter. There is no wbits parameter for zlib.compress(). If you want to specify wbits then you need to use z = zlib.compressobj() and z.compress(). (Again, actually reading the documentation is a huge help here.)

wbits = 15 | 32 for decompression means to look for either a zlib header, or a gzip header. That can't be given for compression, since you need to say what you want. (Ooh, look! That's in the documentation as well.) If you want a zlib header, use wbits = 15. If you want a gzip header, use wbits = 15 | 16.