Home » Python » How to find the mime type of a file in python?

How to find the mime type of a file in python?

Posted by: admin November 1, 2017 Leave a comment

Questions:

Let’s say you want to save a bunch of files somewhere, for instance in BLOBs. Let’s say you want to dish these files out via a web page and have the client automatically open the correct application/viewer.

Assumption: The browser figures out which application/viewer to use by the mime-type (content-type?) header in the HTTP response.

Based on that assumption, in addition to the bytes of the file, you also want to save the MIME type.

How would you find the MIME type of a file? I’m currently on a Mac, but this should also work on Windows.

Does the browser add this information when posting the file to the web page?

Is there a neat python library for finding this information? A WebService or (even better) a downloadable database?

Answers:

The python-magic method suggested by toivotuo is outdated. Python-magic’s current trunk is at Github and based on the readme there, finding the MIME-type, is done like this.

# For MIME types
>>> import magic
>>> mime = magic.Magic(mime=True)
>>> mime.from_file("testdata/test.pdf")
'application/pdf'
>>>

Questions:
Answers:

The mimetypes module in the standard library will determine/guess the MIME type from a file extension.

If users are uploading files the HTTP post will contain the MIME type of the file alongside the data. For example, Django makes this data available as an attribute of the UploadedFile object.

Questions:
Answers:

More reliable way than to use the mimetypes library would be to use the python-magic package.

import magic
m = magic.open(magic.MAGIC_MIME)
m.load()
m.file("/tmp/document.pdf")

This would be equivalent to using file(1).

On Django one could also make sure that the MIME type matches that of UploadedFile.content_type.

Questions:
Answers:

This seems to be very easy

>>> from mimetypes import MimeTypes
>>> import urllib 
>>> mime = MimeTypes()
>>> url = urllib.pathname2url('Upload.xml')
>>> mime_type = mime.guess_type(url)
>>> print mime_type
('application/xml', None)

Please refer Old Post

Questions:
Answers:

There are 3 different libraries that wraps libmagic.

2 of them are available on pypi (so pip install will work):

  • filemagic
  • python-magic

And another, similar to python-magic is available directly in the latest libmagic sources, and it is the one you probably have in your linux distribution.

In Debian the package python-magic is about this one and it is used as toivotuo said and it is not obsoleted as Simon Zimmermann said (IMHO).

It seems to me another take (by the original author of libmagic).

Too bad is not available directly on pypi.

Questions:
Answers:

in python 2.6:

mime = subprocess.Popen("/usr/bin/file --mime PATH", shell=True, \
    stdout=subprocess.PIPE).communicate()[0]

Questions:
Answers:

You didn’t state what web server you were using, but Apache has a nice little module called Mime Magic which it uses to determine the type of a file when told to do so. It reads some of the file’s content and tries to figure out what type it is based on the characters found. And as Dave Webb Mentioned the MimeTypes Module under python will work, provided an extension is handy.

Alternatively, if you are sitting on a UNIX box you can use sys.popen('file -i ' + fileName, mode='r') to grab the MIME type. Windows should have an equivalent command, but I’m unsure as to what it is.

Questions:
Answers:

@toivotuo ‘s method worked best and most reliably for me under python3. My goal was to identify gzipped files which do not have a reliable .gz extension. I installed python3-magic.

import magic

filename = "./datasets/test"

def file_mime_type(filename):
    m = magic.open(magic.MAGIC_MIME)
    m.load()
    return(m.file(filename))

print(file_mime_type(filename))

for a gzipped file it returns:
application/gzip; charset=binary

for an unzipped txt file (iostat data):
text/plain; charset=us-ascii

for a tar file:
application/x-tar; charset=binary

for a bz2 file:
application/x-bzip2; charset=binary

and last but not least for me a .zip file:
application/zip; charset=binary

Questions:
Answers:

The mimetypes module just recognise an file type based on file extension. If you will try to recover a file type of a file without extension, the mimetypes will not works.

Questions:
Answers:

In Python 3.x and webapp with url to the file which couldn’t have an extension or a fake extension. You should install python-magic, using

pip3 install python-magic

For Mac OS X, you should also install libmagic using

brew install libmagic

Code snippet

import urllib
import magic
from urllib.request import urlopen

url = "http://...url to the file ..."
request = urllib.request.Request(url)
response = urlopen(request)
mime_type = magic.from_buffer(response.readline())
print(mime_type)

alternatively you could put a size into the read

import urllib
import magic
from urllib.request import urlopen

url = "http://...url to the file ..."
request = urllib.request.Request(url)
response = urlopen(request)
mime_type = magic.from_buffer(response.read(128))
print(mime_type)

Questions:
Answers:

I ‘ve tried a lot of examples but with Django mutagen plays nicely.

Example checking if files is mp3

from mutagen.mp3 import MP3, HeaderNotFoundError  

try:
    audio = MP3(file)
except HeaderNotFoundError:
    raise ValidationError('This file should be mp3')

The downside is that your ability to check file types is limited, but it’s a great way if you want not only check for file type but also to access additional information.

Questions:
Answers:

2017 Update

No need to go to github, it is on PyPi under a different name:

pip install --user python-magic
# or:
sudo apt install python3-magic  # Ubuntu distro package

The code can be simplified as well:

>>> import magic

>>> magic.from_file('/tmp/img_3304.jpg', mime=True)
'image/jpeg'

Questions:
Answers:

you can use imghdr Python module.