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84 lines
2.8 KiB
Python
84 lines
2.8 KiB
Python
# Originally adapted from https://github.com/aboSamoor/polyglot/blob/master/polyglot/base.py
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import unicodedata
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import pycld2 as cld2
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class UnknownLanguageError(Exception):
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pass
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class Language:
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def __init__(self, choice):
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name, code, confidence, bytesize = choice
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self.code = code
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self.name = name
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self.confidence = float(confidence)
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self.read_bytes = int(bytesize)
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def __str__(self):
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return ("name: {:<12}code: {:<9}confidence: {:>5.1f} "
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"read bytes:{:>6}".format(self.name, self.code,
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self.confidence, self.read_bytes))
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@staticmethod
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def from_code(code):
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return Language(("", code, 100, 0))
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class Detector:
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""" Detect the language used in a snippet of text."""
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def __init__(self, text, quiet=False):
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""" Detector of the language used in `text`.
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Args:
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text (string): unicode string.
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"""
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self.__text = text
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self.reliable = True
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"""False if the detector used Best Effort strategy in detection."""
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self.quiet = quiet
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"""If true, exceptions will be silenced."""
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self.detect(text)
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@staticmethod
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def supported_languages():
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"""Returns a list of the languages that can be detected by pycld2."""
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return [name.capitalize() for name,code in cld2.LANGUAGES if not name.startswith("X_")]
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def detect(self, text):
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"""Decide which language is used to write the text.
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The method tries first to detect the language with high reliability. If
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that is not possible, the method switches to best effort strategy.
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Args:
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text (string): A snippet of text, the longer it is the more reliable we
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can detect the language used to write the text.
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"""
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try:
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reliable, index, top_3_choices = cld2.detect(text, bestEffort=False)
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except cld2.error as e:
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if "input contains invalid UTF-8" in str(e):
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# Fix for https://github.com/LibreTranslate/LibreTranslate/issues/514
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# related to https://github.com/aboSamoor/polyglot/issues/71#issuecomment-707997790
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text = ''.join([l for l in text if unicodedata.category(str(l))[0] not in ('S', 'M', 'C')])
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reliable, index, top_3_choices = cld2.detect(text, bestEffort=False)
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else:
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raise e
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if not reliable:
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self.reliable = False
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reliable, index, top_3_choices = cld2.detect(text, bestEffort=True)
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if not self.quiet and not reliable:
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raise UnknownLanguageError("Try passing a longer snippet of text")
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self.languages = [Language(x) for x in top_3_choices]
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self.language = self.languages[0]
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return self.language
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def __str__(self):
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text = f"Prediction is reliable: {self.reliable}\n"
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text += "\n".join([f"Language {i+1}: {str(l)}"
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for i,l in enumerate(self.languages)])
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return text
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