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Description:

puremagic 1.27

puremagic is a pure python module that will identify a file based off
it’s magic numbers.

It is designed to be minimalistic and inherently cross platform
compatible. It is also designed to be a stand in for python-magic, it
incorporates the functions from_file(filename[, mime]) and
from_string(string[, mime]) however the magic_file() and
magic_string() are more powerful and will also display confidence and
duplicate matches.
It does NOT try to match files off non-magic string. In other words it
will not search for a string within a certain window of bytes like
others might.
Advantages over using a wrapper for ‘file’ or ‘libmagic’:

Faster
Lightweight
Cross platform compatible
No dependencies

Disadvantages:

Does not have as many file types
No multilingual comments
Duplications due to small or reused magic numbers

(Help fix the first two disadvantages by contributing!)

Compatibility

Python 3.7+

Using github ci to run continuous integration tests on listed platforms.

Install from pypy
$ pip install puremagic
On linux environments, you may want to be clear you are using python3
$ python3 -m pip install puremagic

Install from source
In either a virtualenv or globally, simply run:
$ python setup.py install

Usage
“from_file” will return the most likely file extension. “magic_file”
will give you every possible result it finds, as well as the confidence.
import puremagic

filename = "test/resources/images/test.gif"

ext = puremagic.from_file(filename)
# '.gif'

puremagic.magic_file(filename)
# [['.gif', 'image/gif', 'Graphics interchange format file (GIF87a)', 0.7],
# ['.gif', '', 'GIF file', 0.5]]
With “magic_file” it gives each match, highest confidence first:

possible extension(s)
mime type
description
confidence (All headers have to perfectly match to make the list,
however this orders it by longest header, therefore most precise,
first)

If you already have a file open, or raw byte string, you could also use:

from_string
from_stream
magic_string
magic_stream

with open(r"test\resources\video\test.mp4", "rb") as file:
print(puremagic.magic_stream(file))

# [PureMagicWithConfidence(byte_match=b'ftypisom', offset=4, extension='.mp4', mime_type='video/mp4', name='MPEG-4 video', confidence=0.8),
# PureMagicWithConfidence(byte_match=b'iso2avc1mp4', offset=20, extension='.mp4', mime_type='video/mp4', name='MP4 Video', confidence=0.8)]

Script
Usage
$ python -m puremagic [options] filename <filename2>...
Examples
$ python -m puremagic test/resources/images/test.gif
'test/resources/images/test.gif' : .gif

$ python -m puremagic -m test/resources/images/test.gif test/resources/audio/test.mp3
'test/resources/images/test.gif' : image/gif
'test/resources/audio/test.mp3' : audio/mpeg

imghdr replacement
If you are looking for a replacement for the standard library’s depreciated imghdr, you can use puremagic.what()
import puremagic

filename = "test/resources/images/test.gif"

ext = puremagic.what(filename)
# 'gif'

FAQ
The file type is actually X but it’s showing up as Y with higher
confidence?
This can happen when the file’s signature happens to match a subset of a
file standard. The subset signature will be longer, therefore report
with greater confidence, because it will have both the base file type
signature plus the additional subset one.
You don’t have sliding offsets that could better detect plenty of
common formats, why’s that?
Design choice, so it will be a lot faster and more accurate. Without
more intelligent or deeper identification past a sliding offset I don’t
feel comfortable including it as part of a ‘magic number’ library.
Your version isn’t as complete as I want it to be, where else should I
look?
Look into python modules that wrap around libmagic or use something like
Apache Tika.

Acknowledgements
Gary C. Kessler
For use of his File Signature Tables, available at:
http://www.garykessler.net/library/file_sigs.html
Freedesktop.org
For use of their shared-mime-info file, available at:
https://cgit.freedesktop.org/xdg/shared-mime-info/

License
MIT Licenced, see LICENSE, Copyright (c) 2013-2024 Chris Griffith