Class: BetterTranslate::Providers::GeminiProvider

Inherits:
BaseHttpProvider show all
Defined in:
lib/better_translate/providers/gemini_provider.rb

Overview

Google Gemini translation provider

Uses gemini-2.5-flash-lite model for fast, high-quality translations.

Examples:

Basic usage

config = Configuration.new
config.google_gemini_key = ENV['GOOGLE_GEMINI_KEY']
provider = GeminiProvider.new(config)
result = provider.translate_text("Hello", "it", "Italian")
#=> "Ciao"

Constant Summary collapse

API_URL =

Google Gemini API endpoint

"https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-lite:generateContent"
MODEL =

Model to use for translations

"gemini-2.5-flash-lite"

Instance Attribute Summary

Attributes inherited from BaseHttpProvider

#cache, #config, #rate_limiter

Instance Method Summary collapse

Methods inherited from BaseHttpProvider

#build_cache_key, #calculate_backoff, #handle_response, #http_client, #initialize, #log_retry, #make_request, #with_cache

Constructor Details

This class inherits a constructor from BetterTranslate::Providers::BaseHttpProvider

Instance Method Details

#build_prompt(text, target_lang_name) ⇒ String (private)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Build prompt for Gemini API

Parameters:

  • text (String) —

    Text to translate

  • target_lang_name (String) —

    Target language name

Returns:

  • (String) —

    Prompt



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# File 'lib/better_translate/providers/gemini_provider.rb', line 78

def build_prompt(text, target_lang_name)
  base_prompt = "Translate the following text to #{target_lang_name}. " \
                "Return ONLY the translated text, without any explanations. " \
                "Words like VARIABLE_0, VARIABLE_1, etc. are placeholders and must be kept unchanged in the translation.\n\n" \
                "Text: #{text}"

  if config.translation_context && !config.translation_context.empty?
    base_prompt = "Context: #{config.translation_context}\n\n#{base_prompt}"
  end

  base_prompt
end

#extract_translation(response) ⇒ String (private)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Extract translation from API response

Parameters:

  • response (Faraday::Response) —

    HTTP response

Returns:

  • (String) —

    Translated text

Raises:



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# File 'lib/better_translate/providers/gemini_provider.rb', line 124

def extract_translation(response)
  parsed = JSON.parse(response.body)
  translation = parsed.dig("candidates", 0, "content", "parts", 0, "text")

  raise TranslationError, "No translation in response" if translation.nil? || translation.empty?

  translation.strip
rescue JSON::ParserError => e
  raise TranslationError.new(
    "Failed to parse Gemini response",
    context: { error: e.message, body: response.body }
  )
end

#make_generation_request(prompt) ⇒ Faraday::Response (private)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Make generation request to Gemini API

Parameters:

  • prompt (String) —

    Prompt text

Returns:

  • (Faraday::Response) —

    HTTP response



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# File 'lib/better_translate/providers/gemini_provider.rb', line 97

def make_generation_request(prompt)
  url = "#{API_URL}?key=#{config.google_gemini_key}"

  body = {
    contents: [
      {
        parts: [
          { text: prompt }
        ]
      }
    ]
  }

  headers = {
    "Content-Type" => "application/json"
  }

  make_request(:post, url, body: body, headers: headers)
end

#translate_batch(texts, target_lang_code, target_lang_name) ⇒ Array<String>

Translate multiple texts in a batch

Examples:

provider.translate_batch(["Hello", "World"], "it", "Italian")
#=> ["Ciao", "Mondo"]

Parameters:

  • texts (Array<String>) —

    Texts to translate

  • target_lang_code (String) —

    Target language code

  • target_lang_name (String) —

    Target language name

Returns:

  • (Array<String>) —

    Translated texts



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# File 'lib/better_translate/providers/gemini_provider.rb', line 65

def translate_batch(texts, target_lang_code, target_lang_name)
  texts.map { |text| translate_text(text, target_lang_code, target_lang_name) }
end

#translate_text(text, target_lang_code, target_lang_name) ⇒ String

Translate a single text

Examples:

provider.translate_text("Hello world", "it", "Italian")
#=> "Ciao mondo"

Parameters:

  • text (String) —

    Text to translate

  • target_lang_code (String) —

    Target language code

  • target_lang_name (String) —

    Target language name

Returns:

  • (String) —

    Translated text

Raises:



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# File 'lib/better_translate/providers/gemini_provider.rb', line 36

def translate_text(text, target_lang_code, target_lang_name)
  Validator.validate_text!(text)
  Validator.validate_language_code!(target_lang_code)

  cache_key = build_cache_key(text, target_lang_code)

  with_cache(cache_key) do
    prompt = build_prompt(text, target_lang_name)
    response = make_generation_request(prompt)
    extract_translation(response)
  end
rescue ApiError => e
  raise TranslationError.new(
    "Failed to translate text with Gemini: #{e.message}",
    context: { text: text, target_lang: target_lang_code, original_error: e }
  )
end