Internationalization

We use GNU gettext in combination with the python babel library for internationalization.

See also

Some english words have multiple (semantically different) meanings, which may correspond to different words in other languages. Our approach to handle such homonyms is described in the Design section Internationalization (i18n).

Marking, extracting and translating

• Translatable strings have to be marked. In python you can do this in two ways:

  • using n_(). This only marks the string for extraction into internationalization files, but does not translate it.

  • using rs.gettext(). This marks the string, but also replaces it with the translation.

  Be aware that messages that need to be translated, but do not appear explicitly in the code, need to be added manually to the i18n_additional.py file, so that they are then extracted. This applies especially to human-readable descriptions of enum members.

  You can also translate strings in templates, by wrapping them in either of the following. Both of these ways replace the marked string with the appropriate translation.

  • the gettext() function or its common alias _() where appropriate.

  • the {% trans %} / {% endtrans %} environment.

• Marked strings are extracted via the make i18n-extract command.

• The extracted strings are stored in the cdedb.po files in the i18n directory (one file per language) via the make i18n-update command. This also takes care of formatting the PO file. Run (just) this command if you want to update the formatting of the file.

• The make i18n-refresh command combines the two above and should be run, after new strings were added in the code.

• The strings in the cdedb.po file(s) then need to be translated.

• Ultimately pybabel needs to be compiled (make i18n-compile) and the apache restarted (for the changes to take effect in the browser). This can both be done via one command: make reload.

See also

Since the PO message catalogs have a different structure than usual code files, we have a custom diff script and merge driver to handle them more easily. See the Development setup guide for further information.

Checking translations

The make i18n-compile command also performs some basic checks on the PO files. For example it will tell you if a format specifier is missing in a translation. It will also tell you how many untranslated strings there are.

For the german translation file, there should not be any untranslated strings (there exists a test in the test suite, that makes sure of this). You can find untranslated strings in the PO files by searching for ""\n\n (empty quotes followed by a blank line).