Is there a way to decode bytes inside a string object in Python? [duplicate]

Question

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Converting python string into bytes directly without eval() (1 answer)

Closed 7 months ago .

Let me be more clear.

I'm receiving a string in Python like this:

file = "b'x\\x9c\\xb4'"

The type of file is str . But you can see inside of that string the format of a <class 'bytes'> . It was the result of calling str(file) once file was already encoded. I would like to decode it but i don't know how to decode the bytes inside of a string object.

My question is: is there a way to interpret file as bytes instead of str without having to call something like bytes(file, 'utf-8') or file.encode('utf-8') ? The problem with these method is that i would encode the already encoded bytes as i stated before.

Why do i need that?

I'm building an API and i need to send back as a JSON value a significantly big string. Since there was plenty of space for me to compress it, i ended using zlib :

import zlib
file = BIG_STRING
file_compressed = zlib.compress(BIG_STRING.encode(utf-8)) # Since zlib expects a bytes object
send_back({"SOME_BIG_STRING": str(file_compressed)})

I'm sending it back as a string because i can't send it back as a bytes object, it doesn't support that. And if i try to decode it compressed before sending i ended up facing an error:

send_back({"SOME_BIG_STRING": file_compressed.decode('utf-8')})
-> UnicodeDecodeError: utf-8' codec can't decode byte 0x9c in position 1: invalid start byte

And when i receive the same string later in the program, i find myself stuck on the problem described initially.

I'm lacking knowledge right now to be able to do some workaround and couldn't find an answer to this. I'd be extremely grateful if anyone could help me!

Answer 1

Anyway, you can call eval("b'x\\x9c\\xb4'") and get your result b'x\x9c\xb4' if you don't find any other solution. But eval usage isn't recommended in the common case and it will be a bad practice.