catstodon/app/lib/translation_service/deepl.rb

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# frozen_string_literal: true
class TranslationService::DeepL < TranslationService
include JsonLdHelper
def initialize(plan, api_key)
super()
@plan = plan
@api_key = api_key
end
def translate(text, source_language, target_language)
form = { text: text, source_lang: source_language&.upcase, target_lang: target_language, tag_handling: 'html' }
request(:post, '/v2/translate', form: form) do |res|
transform_response(res.body_with_limit)
end
end
def languages
source_languages = [nil] + fetch_languages('source')
# In DeepL, EN and PT are deprecated in favor of EN-GB/EN-US and PT-BR/PT-PT, so
# they are supported but not returned by the API.
target_languages = %w(en pt) + fetch_languages('target')
source_languages.index_with { |language| target_languages.without(nil, language) }
end
private
def fetch_languages(type)
request(:get, "/v2/languages?type=#{type}") do |res|
Oj.load(res.body_with_limit).map { |language| normalize_language(language['language']) }
end
end
def normalize_language(language)
subtags = language.split(/[_-]/)
subtags[0].downcase!
subtags[1]&.upcase!
subtags.join('-')
end
def request(verb, path, **options)
req = Request.new(verb, "#{base_url}#{path}", **options)
req.add_headers(Authorization: "DeepL-Auth-Key #{@api_key}")
req.perform do |res|
case res.code
when 429
raise TooManyRequestsError
when 456
raise QuotaExceededError
when 200...300
yield res
else
raise UnexpectedResponseError
end
end
end
def base_url
if @plan == 'free'
'https://api-free.deepl.com'
else
'https://api.deepl.com'
end
end
def transform_response(str)
json = Oj.load(str, mode: :strict)
raise UnexpectedResponseError unless json.is_a?(Hash)
Translation.new(text: json.dig('translations', 0, 'text'), detected_source_language: json.dig('translations', 0, 'detected_source_language')&.downcase, provider: 'DeepL.com')
rescue Oj::ParseError
raise UnexpectedResponseError
end
end