• gettext and lazy_gettext (usually aliased to _): for translating singular strings.

then wrap the translatable strings with it, e.g. _('Translate me'). During extraction, string literals passed to _ will be added to the generated .po file for each language for later translation.

At runtime, the _ function will return the translation of the given string for the current language, or the given string itself if no translation is available.

In TypeScript/JavaScript, the technique is similar: we import t (simple translation), tn (translation containing a number).

import { t, tn } from "@superset-ui/translation";

Add the LANGUAGES variable to your superset_config.py. Having more than one option inside will add a language selection dropdown to the UI on the right side of the navigation bar.

LANGUAGES = {
    'fr': {'flag': 'fr', 'name': 'French'},
    'zh': {'flag': 'cn', 'name': 'Chinese'},
}

First check if the language code for your target language already exists. Check if the for your target language already exists in the superset/translations directory:

If your language already has a pre-existing translation, skip to the next section

To create a dictionary for a new language, first make sure the necessary dependencies are installed:

Then run the following, where LANGUAGE_CODE is replaced with the language code for your target language:

pybabel init -i superset/translations/messages.pot -d superset/translations -l LANGUAGE_CODE

For instance, to add a translation for Finnish (language code fi), run the following:

pybabel init -i superset/translations/messages.pot -d superset/translations -l fi

This step needs to be done every time application strings change. This happens fairly frequently, so if you want to ensure that your translation has good coverage, this step needs to be run fairly frequently and the updated strings merged to the upstream codebase via PRs. To update the template file superset/translations/messages.pot with current application strings, run the following command:

pybabel extract -F superset/translations/babel.cfg -o superset/translations/messages.pot -k _ -k __ -k t -k tn -k tct .

Do not forget to update this file with the appropriate license information.

Run the following command to update the language files with the new extracted strings.

To perform the translation on MacOS, you can install poedit via Homebrew:

After this, just start the poedit application and open the messages.po file. In the case of the Finnish translation, this would be superset/translations/fi/LC_MESSAGES/messages.po.

To make the translations available on the frontend, we need to convert the PO file into a JSON file. To do this, we need to globally install the npm package po2json.

npm install -g po2json

To convert all PO files to formatted JSON files you can use the po2json.sh script.

./scripts/po2json.sh

If you get errors running po2json, you might be running the Ubuntu package with the same name, rather than the Node.js package (they have a different format for the arguments). If there is a conflict, you may need to update your PATH environment variable or fully qualify the executable path (e.g. /usr/local/bin/po2json instead of po2json). If you get a lot of [null,***] in messages.json, just delete all the null,. For example, is correct while "year":[null,"年"]is incorrect.

Finally, for the translations to take effect we need to compile translation catalogs into binary MO files.