How to set up language files

Inspired by https://phrase.com/blog/posts/i18n-advantages-babel-python/#Integration_with_Jinja2_templates

Add translate statements to jinja2 templates

<title>{% trans %}Page title{% endtrans %}</title>

To parse the jinja templates to extract the messages, first create a file named babel-mapping.ini:

[python: **.py]
[jinja2: **/templates/**.html]
extensions=jinja2.ext.i18n,jinja2.ext.autoescape,jinja2.ext.with_

Then extract the base messages from templates:

pybabel extract -F babel-mapping.ini -o locale/messages.pot ./

This file is not persisted on github.

If the above command gives this ouput:

AttributeError: module 'jinja2.ext' has no attribute 'autoescape'

Just comment out the extensions line in the babel-mapping.ini file:

[python: **.py]
[jinja2: **/templates/**.html]
;extensions=jinja2.ext.i18n,jinja2.ext.autoescape,jinja2.ext.with_

Then rerun the command for extracting base messages.

Now setup a new language (french) using the init command:

pybabel init -d locale -l fr -i locale/messages.pot

Or update an existing language using:

pybabel update -d locale -l fr -i locale/messages.pot

Run compile command to generate MO files:

pybabel compile -d locale -l fr