Setup

[sudo] pip install -r requirements.txt

Compile po files

The po files (human readable) need to be compiled into machine readable mo files before gettext can use them

pybabel compile --domain=helloworld --directory=locale --use-fuzzy

Run

python hello_world.py

Workflow

When working on the application, you might want to add new messages. For example, add the following line to templates/my_template.jinja2:

{{ gettext('Yet another message') }}

Babel can automatically detect that this message was added. First we need to use the extract command to extract all localizable messages from the source files:

pybabel extract --mapping babel.cfg --output-file=locale/helloworld.pot .

Then update the *.po files so they contain the new localizable message:

pybabel update --domain=helloworld --input-file=locale/helloworld.pot --output-dir=locale

You can now see in the git diff for the *.po files where the new message was added, and you can hand-edit these files to localize the new message.

For example, open locale/nb_NO/LC_MESSAGES/helloworld.po and edit

#: templates/my_template.jinja2:3
msgid "Yet another message"
msgstr ""

to

#: templates/my_template.jinja2:3
msgid "Yet another message"
msgstr "Enda en melding"

Poedit is a good editor for doing this. For example, it'll highlight missing translations and suggest translations, and you'll just have to press a keyboard shortcut to apply the suggestion.

Command line aliases

Since the pybabel commands can be quite long, and you might want to use them frequently, it is recommended to add short aliases to these commands to save time