A simple pattern for inlining binary content in a Python script

For simonw/til issue #82 I needed to embed some binary content directly in a Python script.

I wanted to wrap that content to fit within 80 columns.

Here's the format I ended up using:

binary_data = (
    b"x\x9c\xb5VQo\xdb6\x10~\xf7\xaf\xb8*\xc8d\xaf\xae\x94\xd6\xd9V\xb8\xb6"
    b"\xb0\xa0\r\xb0\x01\xc5\x1e\x96\x02{(\x06\x83\x16i\x93+E\xaa$\xd5\xccu\x0c"
    # ...
)

This takes advantage of the fact that Python will automatically join adjacent string or byte literals together if they are separated just by whitespace.

But how best to split the binary string into roughly 80 character chunks?

It turns out the pprint module from the Python standard library can do this for you:

from pprint import pprint

binary_string = open("binary_file", "rb").read()
pprint(binary_string)

Here's that as a more convenient shell one-liner that uses content piped into Python:

cat binary_file | python -c 'from pprint import pprint; import sys; pprint(sys.stdin.buffer.read())'

For example, against this PNG:

cat datasette/static/favicon.png | python -c '
from pprint import pprint
import sys
pprint(sys.stdin.buffer.read())
'

The ouput is:

(b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x00 \x00\x00\x00 '
 b'\x04\x03\x00\x00\x00\x81Tg\xc7\x00\x00\x00\x18PLTE\x00\x00\x00'
 b'\xff\xff\xff\xff\xff\xff\xb7\xb9\xdc\xb1\xb2\xd8\xa9\xaa\xc9\x05'
 b'\x00\x82\x04\x00u\xef\x11B\x8f\x00\x00\x00\x02tRNS\x00\x13\xf2-\x8c\xe6\x00'
 b'\x00\x00eIDATx\xdac\xc0\x04liH \x81\x81\x811\xd9\x18\t\x98\x01\x15\x18\xa3'
 b'\x80\x04,\x02i(\x00(\xa0\xa4\xe4\xa4d\xa4\xa4\x0c\xa2T\x94\x94 \x02 6'
 b')\x02\xe5\xe5\xe9@XV\x0e!\x90TP\xdd\xd0 \xacZ\x8c\x88\x16(/\x83'
 b'\x1b\x9a\x86\xe4Re\x0c-\xa4\x08`\x0fS\x92\xcc`HB\xd6\xa2\x86\x1e\xd9\x89'
 b"\x98\x89\x01\x00b\xe6g\xc5_\xc3\xfa'\x00\x00\x00\x00IEND\xaeB`\x82")

Created 2023-08-19T09:35:44-07:00 · Edit

A simple pattern for inlining binary content in a Python script

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