all Python 3mimetypesfunction

mimetypes.guess_extension()

extensions

Picks one extension for a MIME type — for example, to name a downloaded file from its Content-Type header.

Syntax

ext = mimetypes.guess_extension(type, strict=True)

It returns the extension with the dot ('.json', not 'json'), and None for an unknown type, so building a name without a check fails with TypeError. Header parameters get in the way: cut 'text/html; charset=utf-8' down to 'text/html' first. For types with several extensions the pick depends on the version and on system files.

Examples

import mimetypes
db = mimetypes.MimeTypes()
print(db.guess_extension('application/json'))  # → .json
print(db.guess_extension('text/html; charset=utf-8'))  # → None
print(db.guess_extension('text/html; charset=utf-8'.split(';')[0]))  # → .html

See also

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