Support for the Internationalized Domain Names in Applications (IDNA) protocol as specified in RFC 5891. This is the latest version of the protocol and is sometimes referred to as “IDNA 2008”.
This library also provides support for Unicode Technical Standard 46, Unicode IDNA Compatibility Processing.
This acts as a suitable replacement for the “encodings.idna” module that comes with the Python standard library, but which only supports the older superseded IDNA specification (RFC 3490).
Basic functions are simply executed:
>>> import idna
>>> idna.encode('ドメイン.テスト')
b'xn--eckwd4c7c.xn--zckzah'
>>> print(idna.decode('xn--eckwd4c7c.xn--zckzah'))
ドメイン.テストThis package is available for installation from PyPI:
$ python3 -m pip install idnaFor typical usage, the encode and decode functions will take a
domain name argument and perform a conversion to A-labels or U-labels
respectively.
>>> import idna
>>> idna.encode('ドメイン.テスト')
b'xn--eckwd4c7c.xn--zckzah'
>>> print(idna.decode('xn--eckwd4c7c.xn--zckzah'))
ドメイン.テストYou may use the codec encoding and decoding methods using the
idna.codec module:
>>> import idna.codec
>>> print('домен.испытание'.encode('idna2008'))
b'xn--d1acufc.xn--80akhbyknj4f'
>>> print(b'xn--d1acufc.xn--80akhbyknj4f'.decode('idna2008'))
домен.испытаниеConversions can be applied at a per-label basis using the ulabel or
alabel functions if necessary:
>>> idna.alabel('测试')
b'xn--0zwm56d'As described in RFC 5895, the IDNA specification does not normalize input from different potential ways a user may input a domain name. This functionality, known as a “mapping”, is considered by the specification to be a local user-interface issue distinct from IDNA conversion functionality.
This library provides one such mapping that was developed by the Unicode Consortium. Known as Unicode IDNA Compatibility Processing, it provides for both a regular mapping for typical applications, as well as a transitional mapping to help migrate from older IDNA 2003 applications. Strings are preprocessed according to Section 4.4 “Preprocessing for IDNA2008” prior to the IDNA operations.
For example, “Königsgäßchen” is not a permissible label as LATIN CAPITAL LETTER K is not allowed (nor are capital letters in general). UTS 46 will convert this into lower case prior to applying the IDNA conversion.
>>> import idna
>>> idna.encode('Königsgäßchen')
...
idna.core.InvalidCodepoint: Codepoint U+004B at position 1 of 'Königsgäßchen' not allowed
>>> idna.encode('Königsgäßchen', uts46=True)
b'xn--knigsgchen-b4a3dun'
>>> print(idna.decode('xn--knigsgchen-b4a3dun'))
königsgäßchenTransitional processing provides conversions to help transition from the older 2003 standard to the current standard. For example, in the original IDNA specification, the LATIN SMALL LETTER SHARP S (ß) was converted into two LATIN SMALL LETTER S (ss), whereas in the current IDNA specification this conversion is not performed.
>>> idna.encode('Königsgäßchen', uts46=True, transitional=True)
'xn--knigsgsschen-lcb0w'Implementers should use transitional processing with caution, only in rare cases where conversion from legacy labels to current labels must be performed (i.e. IDNA implementations that pre-date 2008). For typical applications that just need to convert labels, transitional processing is unlikely to be beneficial and could produce unexpected incompatible results.
Function calls from the Python built-in encodings.idna module are
mapped to their IDNA 2008 equivalents using the idna.compat module.
Simply substitute the import clause in your code to refer to the new
module name.