CODEWITHSUNDEEP
pythonpython-3.xtypeerrorzlibbytesio
Dan
Dan

Reputation: 2509

Convert from '_io.BytesIO' to a bytes-like object in python3.6?

I am using this function to uncompress the body of a HTTP response if it is compressed with gzip, compress or deflate.

def uncompress_body(self, compression_type, body):
    if compression_type == 'gzip' or compression_type == 'compress':
        return zlib.decompress(body)
    elif compression_type == 'deflate':
        compressor = zlib.compressobj(9, zlib.DEFLATED, -zlib.MAX_WBITS)
        compressed = compressor.compress(body)
        compressed += compressor.flush()
        return base64.b64encode(compressed)

    return body

However python throws this error message.

TypeError: a bytes-like object is required, not '_io.BytesIO'

on this line:

return zlib.decompress(body)

Essentially, how do I convert from '_io.BytesIO' to a bytes-like object?

Upvotes: 93

Views: 120095

Answers (4)

rhoitjadhav
rhoitjadhav

Reputation: 903

I know its late for the answer but if anyone finds into same issue then the below code snippet might be useful.

from io import BytesIO


data = BytesIO(b'Some data')

bytes_data = data.getvalue()

print(bytes_data, type(bytes_data)

Output

b'Some data' <class 'bytes'>

Upvotes: 5

Nwawel A Iroume
Nwawel A Iroume

Reputation: 1369

b = io.BytesIO()
image = PIL.Image.open(path_to_image) # ie 'image.png'
image.save(b, format='PNG')
b.getbuffer().tobytes() # b'\x89PNG\r\n\x1a\n\x00 ...

Upvotes: 5

Alexander Pacha
Alexander Pacha

Reputation: 9730

In case you write into the object first, make sure to reset the stream before reading:

>>> b = io.BytesIO()
>>> image = PIL.Image.open(path_to_image)
>>> image.save(b, format='PNG')
>>> b.seek(0)
>>> b.read()
b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x06\xcf\x00\x00\x03W\x08\x02\x00'

or directly get the data with getvalue

>>> b.getvalue()
b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x06\xcf\x00\x00\x03W\x08\x02\x00'

Upvotes: 63

wim
wim

Reputation: 363043

It's a file-like object. Read them:

>>> b = io.BytesIO(b'hello')
>>> b.read()
b'hello'

If the data coming in from body is too large to read into memory, you'll want to refactor your code and use zlib.decompressobj instead of zlib.decompress.

Upvotes: 109

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