MIME Type Lookup

import mimetypes

# Guess MIME type from a filename or URL
mime_type, encoding = mimetypes.guess_type('report.pdf')
print(mime_type)   # application/pdf
print(encoding)    # None

print(mimetypes.guess_type('archive.tar.gz'))   # ('application/x-tar', 'gzip')
print(mimetypes.guess_type('style.css'))        # ('text/css', None)
print(mimetypes.guess_type('data.json'))        # ('application/json', None)
print(mimetypes.guess_type('image.svg'))        # ('image/svg+xml', None)

# Guess extension from MIME type
ext = mimetypes.guess_extension('image/jpeg')
print(ext)  # .jpeg (or .jpg depending on platform)

# Add a custom mapping
mimetypes.add_type('application/x-custom', '.myext')

# List all known types
for ext, mime in list(mimetypes.types_map.items())[:5]:
    print(f"{ext:15s} -> {mime}")