Ethereum Name Service (ENS) Name Normalizer
Project description
ENS Normalize Python
- Python implementation of the ENS Name Normalization Standard. Thanks to Adraffy for his leadership in coordinating the definition of this standard with the ENS community.
- 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
- name - a full domain name, e.g.
nick.eth
- label - a part of a name separated by a dot, e.g.
nick
andeth
are labels innick.eth
- normalized name - name that is already in normalized form according to the ENS Normalization Standard
- normalizable name - name that is normalized or that can be converted into a normalized name using
ens_normalize
- disallowed name - name that is not normalized or normalizable
- curable name - name that may be disallowed but can still be converted into a normalized name using
ens_cure
- fatal error - a
DisallowedNameError
object thrown byens_normalize
that contains only general information about the error and no possible fixes - curable error - a
CurableError
object (inherits fromDisallowedNameError
) thrown byens_normalize
that contains information about a possible fix for the error
Usage
The package is available on pypi
pip install ens-normalize
Normalize an ENS name:
from ens_normalize import ens_normalize
# str -> str
# raises DisallowedNameError for disallowed names
# output ready for namehash
ens_normalize('Nick.ETH')
# 'nick.eth'
# note: does not enforce .eth TLD 3-character minimum
Inspect issues with names that cannot be normalized:
from ens_normalize import DisallowedNameError
# added a hidden "zero width joiner" character
try:
ens_normalize('Nick.ETH')
# Catch the first normalization error (the name we are attempting to normalize could have more than one error).
except DisallowedNameError 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
if isinstance(e, CurableError):
# information about the disallowed substring
print(e.disallowed_sequence_info)
# 'This invisible character is disallowed'
# starting index of the disallowed substring in the input string
# (counting in Unicode code points)
print(e.index)
# 2
# the disallowed substring
# (use repr() to "see" the invisible character)
print(repr(e.disallowed))
# '\u200d'
# a suggestion for fixing the first error (there might be more errors)
print(repr(e.suggested))
# ''
# replacing the disallowed substring with this empty string represents that the disallowed substring should 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 attempt conversion of disallowed names into normalized names:
from ens_normalize import ens_cure
# input name with disallowed zero width joiner and '?'
# str -> str
ens_cure('Nick?.ETH')
# 'nick.eth'
# ZWJ and '?' are removed, no error is raised
# note: this function is not a part of the ENS Normalization Standard
# note: might still raise DisallowedNameError for certain names, which cannot be cured, e.g.
ens_cure('?')
# DisallowedNameError: The name is empty
ens_cure('0χх0.eth')
# DisallowedNameError: Contains visually confusing characters that are disallowed
Format names with fully-qualified emoji:
from ens_normalize import ens_beautify
# 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: in addition to beautifying emojis, ens_beautify converts the character 'ξ' (Greek lowercase 'Xi') to 'Ξ' (Greek uppercase 'Xi', a.k.a. the Ethereum symbol) in labels that contain no other Greek characters
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 normalizable name, you can find out how the input is transformed during normalization:
from ens_normalize import ens_transformations
# Returns a list of transformations (substring -> string)
# that have been applied to the input during normalization.
# NormalizationTransformation has the same fields as CurableError:
# - 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 DisallowedNameError as e:
# Even if the name is invalid according to the ENS Normalization Standard,
# we can try to automatically remove disallowed characters.
try:
print(ens_cure(name))
except DisallowedLabelError as e:
# The name cannot be automatically fixed.
print('Fatal error:', e)
You can run many of the above functions at once. It is faster than running all of them sequentially.
from ens_normalize import ens_process
# use only the do_* flags you need
ens_process("Nàme🧙♂️1⃣.eth",
do_normalize=True,
do_beautify=True,
do_tokenize=True,
do_transformations=True,
do_cure=True,
)
# ENSProcessResult(
# normalized='nàme🧙\u200d♂1⃣.eth',
# beautified='nàme🧙\u200d♂️1️⃣.eth',
# tokens=[...],
# cured='nàme🧙\u200d♂1⃣.eth',
# cures=[], # This is the list of cures that were applied to the input (in this case, none).
# error=None, # This is the exception raised by ens_normalize().
# # It is a DisallowedNameError or CurableError if the error is curable.
# transformations=[
# NormalizationTransformation(code="MAPPED", index=0, disallowed="N", suggested="n"),
# NormalizationTransformation(code="FE0F", index=4, disallowed="🧙♂️", suggested="🧙♂")
# ])
List of all DisallowedNameError
types
For fatal errors (not curable), it is challenging to communicate the normalization error as a problem with a specific substring.
DisallowedNameErrorType |
General info |
---|---|
EMPTY_NAME |
The name is empty |
NSM_REPEATED |
Contains a repeated non-spacing mark |
NSM_TOO_MANY |
Contains too many consecutive non-spacing marks |
CONF_WHOLE |
Contains visually confusing characters that are disallowed |
List of all CurableError
types
Curable errors contain additional information about the disallowed substring.
CurableErrorType |
General info | Disallowed sequence info |
---|---|---|
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_LABEL |
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 |
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_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 |
---|---|---|
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:
-
Requirements:
-
Set the hash of the latest commit from the JavaScript library inside package.json
-
Run the updater:
cd tools/updater npm start
-
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 theNormalizationData.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.
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