Validate Localized Resources

Oct 20, 2020 · Follow on Twitter and Mastodon swiftlocalizationci

In this post, we’ll look at a way to validate app localizations and integrate it into Fastlane and any CI tools and processes that you may have in place.

Background

Localization is good, even when having a single language. Separating localized texts from your code makes the code easier to read and texts easier to maintain.

When you support multiple languages, you may use a cloud-based tool like Lokalise to let a team of translators translate your app without access to the raw resources.

When you add new language keys, you may have empty placeholders in some languages until your translators have had a chance to translate them. To prevent these placeholders to end up in production, you should add string validation as part of your release process.

grep to the rescue

You can use grep to check for the occurrence of a string within a file. The following checks for empty keys within an English localization file in a certain folder:

grep "= \"\";" <PATH TO LOCALIZED FOLDER>/en.lproj/Localizable.strings

This will output empty translations, if any, or exit if the file doesn’t contain any empty keys. We can assign this to a build script variable, to control parts of our build process.

Fastlane to the rescue

If you use Fastlane, you can add this new lane to help you validate a localized file:

lane :l10n_validate do |options|
  locale = options[:locale]
  if locale == nil or locale.empty?
    UI.user_error!("Missing parameter 'locale'")
  end
  file = "<PATH TO LOCALIZED FOLDER>/" + locale + ".lproj/Localizable.strings"
  if !sh('cd .. && grep "= \"\";" ' + file + ' || true').empty?
    UI.user_error!(file + " has empty translations!")
  end
end

You can call this lane from the Terminal, as well as from other lanes:

fastlane l10n_validate locale:de

If the localized file contains empty translations, Fastlane will fail with a bright red error text.

If your app supports multiple languages, you can add a lane to validate all locales at once:

lane :l10n_validate_all do |options|
  l10n_validate(locale: "da")
  l10n_validate(locale: "de")
  l10n_validate(locale: "en")
  l10n_validate(locale: "fi")
  l10n_validate(locale: "pl")
  l10n_validate(locale: "sv")
end

You can now run l10n_validate_all to verify that all translations are complete. This makes it possible to e.g. abort release distributions to App Store Connect.

Temporary translations

You probably use temporary strings for your main development language, to avoid having empty strings in the app until all translations are done.

If so, I’d suggest that you establish a pattern that you use in your temporary strings, e.g. a term like <Temp> that otherwise aren’t used in real translations.

This lets you add a second grep to your validation, to detect any occurrences of that word:

lane :l10n_validate do |options|
  locale = options[:locale]
  if locale == nil or locale.empty?
    UI.user_error!("Missing parameter 'locale'")
  end
  file = "<PATH TO LOCALIZED FOLDER>/" + locale + ".lproj/Localizable.strings"
  if !sh('cd .. && grep "= \"\";" ' + file + ' || true').empty?
    UI.user_error!(file + " has empty translations!")
  end
  if !sh('cd .. && grep <Temp> ' + file + ' || true').empty?
    UI.user_error!(file + " has temp translations!")
  end
end

You can take this further to include other localized resources, like Localized.stringsdict.

Conclusion

Validating your app’s localized strings resources is a good way to protect your app from being released with temporary or missing translations. I hope you find this approach useful.

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