ens-normalize 1.9.0

Ethereum Name Service (ENS) Name Normalizer

ENS Normalize Python

• Python implementation of the ENS Name Normalization Standard. Thanks to Adraffy for his leadership in coordinating the definition of this standard.
• Passes 100% of the official validation tests (validated automatically with pytest, see below).
• Passes an additional suite of further tests for compatibility with the official Javascript reference implementation and code testing coverage.
• Based on JavaScript implementation version 1.9.0.

Glossary

• disallowed name - name that cannot be converted into a valid normalized form using ENS Name Normalization Standard
• valid name - name that is normalized or normalizable by the standard
• fixable errors - DisallowedLabelErrors for which fields disallowed, index, suggested, and disallowed_sequence_info are not None

Usage

The package is available on pypi

pip install ens-normalize

Import the main functions provided by this library:

from ens_normalize import ens_normalize, ens_beautify

Normalize an ENS name:

# str -> str
# raises DisallowedLabelError for disallowed names
# output ready for namehash
ens_normalize('Nick.ETH')
# 'nick.eth'
# note: does not enforce .eth TLD 3-character minimum

Catch disallowed names:

# added a hidden "zero width joiner" character
try:
    ens_normalize('Ni‍ck.ETH')
# Catch the first disallowed substring (there might be more).
except DisallowedLabelError as e:
    # error code
    print(e.code)
    # INVISIBLE
    
    # a message about why the input is disallowed
    print(e.general_info)
    # Contains a disallowed invisible character
    
    # starting index of the disallowed substring in the input string
    # (counting in Unicode code points)
    print(e.index)
    # 2

    # information about the disallowed substring
    print(e.disallowed_sequence_info)
    # 'This invisible character is disallowed'

    # the disallowed substring
    # (use repr() to "see" the invisible character)
    print(repr(e.disallowed))
    # '\u200d'

    # a suggestion for fixing the error
    print(repr(e.suggested))
    # ''
    # empty string means that the disallowed substring has to be removed

    # You may be able to fix this error by replacing e.disallowed
    # with e.suggested in the input string.
    # Fields index, disallowed_sequence_info, disallowed, and suggested are not None only for fixable errors.
    # Other errors might be found even after applying this suggestion.

You can force conversion of disallowed names into valid names:

# input name with disallowed zero width joiner and '?'
# str -> str
ens_force_normalize('Ni‍ck?.ETH')
# 'nick.eth'
# ZWJ and '?' are removed, no error is raised
# note: force conversion is not standardized

# note: might still raise DisallowedLabelError for certain names, which can not be force normalized, e.g.
ens_force_normalize('abc..eth')
# DisallowedLabelError: Contains a disallowed empty label

Format names with fully-qualified emoji:

# works like ens_normalize()
# output ready for display
ens_beautify('1⃣2⃣.eth')
# '1️⃣2️⃣.eth'

# note: normalization is unchanged:
# ens_normalize(ens_beautify(x)) == ens_normalize(x)
# note: except beautifying emojis, it capitalizes the letter 'ξ' to 'Ξ' (Ethereum symbol) in non-Greek labels

Generate detailed label analysis:

from ens_normalize import ens_tokenize
# str -> List[Token]
# always returns a tokenization of the input
ens_tokenize('Nàme‍🧙‍♂.eth')
# [TokenMapped(cp=78, cps=[110], type='mapped'),
#  TokenNFC(input=[97, 768], cps=[224], type='nfc'),
#  TokenValid(cps=[109, 101], type='valid'),
#  TokenDisallowed(cp=8205, type='disallowed'),
#  TokenEmoji(emoji=[129497, 8205, 9794, 65039],
#             input=[129497, 8205, 9794],
#             cps=[129497, 8205, 9794],
#             type='emoji'),
#  TokenStop(cp=46, type='stop'),
#  TokenValid(cps=[101, 116, 104], type='valid')]

For a valid name, you can find out how the input was transformed during normalization:

# Returns a list of transformations (substring -> string)
# that have been applied to the input during normalization.
# NormalizationTransformation has the same fields as DisallowedLabelError:
# - code
# - general_info
# - disallowed_sequence_info
# - index
# - disallowed
# - suggested
ens_transformations('Nàme🧙‍♂️.eth')
# [NormalizationTransformation(code="MAPPED", index=0, disallowed="N", suggested="n"),
#  NormalizationTransformation(code="FE0F", index=4, disallowed="🧙‍♂️", suggested="🧙‍♂")]

An example normalization workflow:

name = 'Nàme🧙‍♂️.eth'
try:
    normalized = ens_normalize(name)
    print('Normalized:', normalized)
    # Normalized: nàme🧙‍♂.eth
    # Success!

     # was the input transformed by the normalization process?
    if name != normalized:
        # Let's check how the input was changed:
        for t in ens_transformations(name):
            print(repr(t)) # use repr() to print more information
        # NormalizationTransformation(code="MAPPED", index=0, disallowed="N", suggested="n")
        # NormalizationTransformation(code="FE0F", index=4, disallowed="🧙‍♂️", suggested="🧙‍♂")
        #                              invisible character inside emoji ^
except DisallowedLabelError as e:
    # Even if the name cannot be normalized
    # we still may be able to suggest a possible fix (for fixable errors).
    print('Error:', e)
    print('Try removing', e.disallowed, 'at index', e.start)

You can run all of the above functions at once. It is faster than run all of them sequentially.

# use only the do_* flags you need
ens_process("Nàme🧙‍♂️1⃣.eth",
    do_normalize=True,
    do_beautify=True,
    do_tokenize=True,
    do_transformations=True,
)
# ENSProcessResult(
#   normalized='nàme🧙\u200d♂1⃣.eth',
#   beautified='nàme🧙\u200d♂️1️⃣.eth',
#   tokens=[...],
#   disallowed_label_error=None, # this is the exception raised by ens_normalize()
#   transformations=[
#     NormalizationTransformation(code="MAPPED", index=0, disallowed="N", suggested="n"),
#     NormalizationTransformation(code="FE0F", index=4, disallowed="🧙‍♂️", suggested="🧙‍♂")
#   ])

List of all DisallowedLabelError types

For some errors, it is challenging to communicate the normalization error as a problem with a specific substring. For these errors (see 3rd table column) the index, disallowed_sequence_info, disallowed and suggested fields will be None.

DisallowedLabelErrorType	General info	Disallowed sequence info	Potential resolution of error
UNDERSCORE	Contains an underscore in a disallowed position	An underscore is only allowed at the start of a label	✅
HYPHEN	Contains the sequence '--' in a disallowed position	Hyphens are disallowed at the 2nd and 3rd positions of a label	✅
EMPTY	Contains a disallowed empty label	Empty labels are not allowed, e.g. abc..eth	✅
CM_START	Contains a combining mark in a disallowed position at the start of the label	A combining mark is disallowed at the start of a label	✅
CM_EMOJI	Contains a combining mark in a disallowed position after an emoji	A combining mark is disallowed after an emoji	✅
NSM_REPEATED	Contains a repeated non-spacing mark	None	❌
NSM_TOO_MANY	Contains too many consecutive non-spacing marks	None	❌
DISALLOWED	Contains a disallowed character	This character is disallowed	✅
INVISIBLE	Contains a disallowed invisible character	This invisible character is disallowed	✅
FENCED_LEADING	Contains a disallowed character at the start of a label	This character is disallowed at the start of a label	✅
FENCED_MULTI	Contains a disallowed consecutive sequence of characters	Characters in this sequence cannot be placed next to each other	✅
FENCED_TRAILING	Contains a disallowed character at the end of a label	This character is disallowed at the end of a label	✅
CONF_WHOLE	Contains visually confusing characters that are disallowed	None	❌
CONF_MIXED	Contains visually confusing characters from different scripts that are disallowed	This character is disallowed because it is visually confusing with another character from a different script	✅

List of all normalization transformations

NormalizationTransformationType	General info	Disallowed sequence info	Transform details
IGNORED	Contains disallowed "ignored" characters that have been removed	This character is ignored during normalization and has been automatically removed	✅
MAPPED	Contains a disallowed character that has been replaced by a normalized sequence	This character is disallowed and has been automatically replaced by a normalized sequence	✅
FE0F	Contains a disallowed variant of an emoji which has been replaced by an equivalent normalized emoji	This emoji has been automatically fixed to remove an invisible character	✅
NFC	Contains a disallowed sequence that is not "NFC normalized" which has been replaced by an equivalent normalized sequence	This sequence has been automatically normalized into NFC canonical form	✅

Develop

Update this library to the latest ENS normalization specification (optional)

This library uses files defining the normalization standard directly from the official Javascript implementation. When the standard is updated with new characters, this library can be updated by running the following steps:

1. Requirements:

   • Node.js >= 18
   • npm

2. Set the hash of the latest commit from the JavaScript library inside package.json

3. Run the updater:

   cd tools/updater
   npm start
   

4. Update NormalizationData.VERSION:
   This library keeps cache files in $HOME/.cache/ens_normalize to speed up loading. To make sure existing users regenerate their cache after a version update, please increment the NormalizationData.VERSION constant in normalization.py. The first import of the new version will automatically regenerate the cache.

Build and test

Installs dependencies, runs validation tests and builds the wheel.

1. Install requirements:

   • Python
   • Poetry

2. Install dependencies:

   poetry install
   

3. Run tests (including official validation tests):

   poetry run pytest
   

4. Build Python wheel:

   poetry build