Claire
3 years ago
commit
692963d43b
@ -1,101 +0,0 @@
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# frozen_string_literal: true
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class LanguageDetector
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include Singleton
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WORDS_THRESHOLD = 4
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RELIABLE_CHARACTERS_RE = /[\p{Hebrew}\p{Arabic}\p{Syriac}\p{Thaana}\p{Nko}\p{Han}\p{Katakana}\p{Hiragana}\p{Hangul}\p{Thai}]+/m
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def initialize
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@identifier = CLD3::NNetLanguageIdentifier.new(1, 2048)
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end
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def detect(text, account)
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input_text = prepare_text(text)
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return if input_text.blank?
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detect_language_code(input_text) || default_locale(account)
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end
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def language_names
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@language_names = CLD3::TaskContextParams::LANGUAGE_NAMES.map { |name| iso6391(name.to_s).to_sym }.uniq
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end
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private
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def prepare_text(text)
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simplify_text(text).strip
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end
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def unreliable_input?(text)
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!reliable_input?(text)
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end
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def reliable_input?(text)
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sufficient_text_length?(text) || language_specific_character_set?(text)
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end
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def sufficient_text_length?(text)
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text.split(/\s+/).size >= WORDS_THRESHOLD
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end
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def language_specific_character_set?(text)
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words = text.scan(RELIABLE_CHARACTERS_RE)
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if words.present?
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words.reduce(0) { |acc, elem| acc + elem.size }.to_f / text.size > 0.3
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else
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false
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end
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end
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def detect_language_code(text)
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return if unreliable_input?(text)
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result = @identifier.find_language(text)
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iso6391(result.language.to_s).to_sym if result&.reliable?
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end
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def iso6391(bcp47)
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iso639 = bcp47.split('-').first
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# CLD3 returns grandfathered language code for Hebrew
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return 'he' if iso639 == 'iw'
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ISO_639.find(iso639).alpha2
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end
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def simplify_text(text)
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new_text = remove_html(text)
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new_text.gsub!(FetchLinkCardService::URL_PATTERN, '\1')
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new_text.gsub!(Account::MENTION_RE, '')
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new_text.gsub!(Tag::HASHTAG_RE) { |string| string.gsub(/[#_]/, '#' => '', '_' => ' ').gsub(/[a-z][A-Z]|[a-zA-Z][\d]/) { |s| s.insert(1, ' ') }.downcase }
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new_text.gsub!(/:#{CustomEmoji::SHORTCODE_RE_FRAGMENT}:/, '')
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new_text.gsub!(/\s+/, ' ')
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new_text
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end
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def new_scrubber
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scrubber = Rails::Html::PermitScrubber.new
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scrubber.tags = %w(br p)
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scrubber
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end
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def scrubber
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@scrubber ||= new_scrubber
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end
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def remove_html(text)
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text = Loofah.fragment(text).scrub!(scrubber).to_s
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text.gsub!('<br>', "\n")
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text.gsub!('</p><p>', "\n\n")
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text.gsub!(/(^<p>|<\/p>$)/, '')
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text
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end
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def default_locale(account)
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account.user_locale&.to_sym || I18n.default_locale if account.local?
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end
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end
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@ -1,134 +0,0 @@
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# frozen_string_literal: true
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require 'rails_helper'
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describe LanguageDetector do
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describe 'prepare_text' do
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it 'returns unmodified string without special cases' do
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string = 'just a regular string'
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result = described_class.instance.send(:prepare_text, string)
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expect(result).to eq string
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end
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it 'collapses spacing in strings' do
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string = 'The formatting in this is very odd'
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result = described_class.instance.send(:prepare_text, string)
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expect(result).to eq 'The formatting in this is very odd'
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end
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it 'strips usernames from strings before detection' do
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string = '@username Yeah, very surreal...! also @friend'
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result = described_class.instance.send(:prepare_text, string)
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expect(result).to eq 'Yeah, very surreal...! also'
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end
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it 'strips URLs from strings before detection' do
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string = 'Our website is https://example.com and also http://localhost.dev'
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result = described_class.instance.send(:prepare_text, string)
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expect(result).to eq 'Our website is and also'
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end
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it 'converts #hashtags back to normal text before detection' do
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string = 'Hey look at all the #animals and #FishAndChips'
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result = described_class.instance.send(:prepare_text, string)
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expect(result).to eq 'Hey look at all the animals and fish and chips'
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end
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end
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describe 'detect' do
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let(:account_without_user_locale) { Fabricate(:user, locale: nil).account }
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let(:account_remote) { Fabricate(:account, domain: 'joinmastodon.org') }
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it 'detects english language for basic strings' do
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strings = [
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"Hello and welcome to mastodon how are you today?",
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"I'd rather not!",
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"a lot of people just want to feel righteous all the time and that's all that matters",
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]
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strings.each do |string|
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result = described_class.instance.detect(string, account_without_user_locale)
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expect(result).to eq(:en), string
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end
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end
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it 'detects spanish language' do
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string = 'Obtener un Hola y bienvenidos a Mastodon. Obtener un Hola y bienvenidos a Mastodon. Obtener un Hola y bienvenidos a Mastodon. Obtener un Hola y bienvenidos a Mastodon'
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result = described_class.instance.detect(string, account_without_user_locale)
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expect(result).to eq :es
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end
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describe 'when language can\'t be detected' do
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it 'uses nil when sent an empty document' do
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result = described_class.instance.detect('', account_without_user_locale)
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expect(result).to eq nil
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end
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describe 'because of a URL' do
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it 'uses nil when sent just a URL' do
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string = 'http://example.com/media/2kFTgOJLXhQf0g2nKB4'
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cld_result = CLD3::NNetLanguageIdentifier.new(0, 2048).find_language(string)
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expect(cld_result).not_to eq :en
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result = described_class.instance.detect(string, account_without_user_locale)
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expect(result).to eq nil
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end
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end
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describe 'with an account' do
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it 'uses the account locale when present' do
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account = double(user_locale: 'fr')
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result = described_class.instance.detect('', account)
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expect(result).to eq nil
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end
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it 'uses nil when account is present but has no locale' do
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result = described_class.instance.detect('', account_without_user_locale)
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expect(result).to eq nil
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end
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end
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describe 'with an `en` default locale' do
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it 'uses nil for undetectable string' do
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result = described_class.instance.detect('', account_without_user_locale)
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expect(result).to eq nil
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end
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end
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describe 'remote user' do
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it 'detects Korean language' do
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string = '안녕하세요'
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result = described_class.instance.detect(string, account_remote)
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expect(result).to eq :ko
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end
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end
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describe 'with a non-`en` default locale' do
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around(:each) do |example|
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before = I18n.default_locale
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I18n.default_locale = :ja
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example.run
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I18n.default_locale = before
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end
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it 'uses nil for undetectable string' do
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string = ''
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result = described_class.instance.detect(string, account_without_user_locale)
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expect(result).to eq nil
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end
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end
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end
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end
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end
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