Converting type bytes to string in Python

Question

I'm having an hard time converting the output of a websocket connection to regular string and later to json.

Here is what a simple message looks like:

msg = await ws.recv()
print(msg)

    b'\xabVJ-K\xcd+Q\xb2R*.M*N.\xcaLJU\xd2QJ\xceH\xcc\xcbK\xcd\x01\x89\x16\xe4\x97\xe8\x97d&g\xa7\x16Y\xb9\x86x\xe8\x86\x06\xbb\x84(\xd5\x02\x00'

I tried the following: print(str(msg, 'utf-8')) But i got the following error:

UnicodeDecodeError: 'utf-8' codec can't decode byte 0xab in position 0: invalid start byte

The same happens if i try .decode("utf-8") Can anyone help me find what i'm doing wrong here? Thanks in advance!

Does this answer your question? [Convert bytes to a string](https://stackoverflow.com/questions/606191/convert-bytes-to-a-string) — Brian61354270, Oct 06 '20 at 20:32
Are you sure the message is a string? It might be a binary message. — Barmar, Oct 06 '20 at 20:32
@Brian I tried to use .decode("utf-8"), but i'll still get the error — JayK23, Oct 06 '20 at 20:33
The issue is how the bytes are intended to be interpreted. Some parts are likely to be binary information, other parts may be text strings. You need to extract the different parts and process them appropriately. — Barmar, Oct 06 '20 at 20:35
You need to check the application protocol specification to see how to parse the message. — Barmar, Oct 06 '20 at 20:36
Only thing i found on the docs is the following, but i don't know if it has to do with my problem: "All the messages returning from WebSocket API are optimized by Deflate compression. Users are expected to decompress the messages by their own means(Compression and decompression through the inflate algorithm)." — JayK23, Oct 06 '20 at 20:38

score 1 · Answer 1 · answered Oct 06 '20 at 20:50

The messages are optimized by Deflate compression. All i had to do was to inflate the message:

async def inflate(data):
    decompress = zlib.decompressobj(-zlib.MAX_WBITS)  # see above
    inflated = decompress.decompress(data)
    inflated += decompress.flush()
    return inflated

I found the code here: https://github.com/chopinvan/The-Unofficial-OKEX-Websocket-Bot/blob/master/okex_websocket.py

Converting type bytes to string in Python

1 Answers1