documentation changes

docs/extending.rst

@@ -5,7 +5,7 @@ Paperless development
 
 This section describes the steps you need to take to start development on paperless-ng.
 
-1.  Check out the source from github. The repository is organized in the following way:
+Check out the source from github. The repository is organized in the following way:
 
 *   ``master`` always represents the latest release and will only see changes
     when a new release is made.
@@ -13,6 +13,8 @@ This section describes the steps you need to take to start development on paperl
 *   ``feature-X`` contain bigger changes that will be in some release, but not
     necessarily the next one.
 
+When making functional changes to paperless, *always* make your changes on the ``dev`` branch.
+
 Apart from that, the folder structure is as follows:
 
 *   ``docs/`` - Documentation.
@@ -40,7 +42,9 @@ To do the setup you need to perform the steps from the following chapters in a c
     .. code:: shell-session
 
         mkdir -p consume media
-5. You can now either ... :
+
+5.  You can now either ...
+
     *  install redis or 
     *  use the included scripts/start-services.sh to use docker to fire up a redis instance (and some other services such as tika, gotenberg and a postgresql server) or
     *  spin up a bare redis container 
@@ -48,16 +52,19 @@ To do the setup you need to perform the steps from the following chapters in a c
         .. code:: shell-session
 
             docker run -d -p 6379:6379 -restart unless-stopped redis:latest
+
 6.  Install the python dependencies by performing in the src/ directory.
 
     .. code:: shell-session
 
         pipenv install --dev
+
 7.  Generate the static UI so you can perform a login to get session that is required for frontend development (this needs to be done one time only). From root folder:
 
     .. code:: shell-session
 
         compile-frontend.sh
+
 8.  Apply migrations and create a superuser for your dev instance:
 
     .. code:: shell-session
@@ -152,6 +159,92 @@ This will build the front end and put it in a location from which the Django ser
 it as static content. This way, you can verify that authentication is working.
 
 
+Localization
+============
+
+Paperless is available in many different languages. Since paperless consists both of a django
+application and an Angular front end, both these parts have to be translated separately.
+
+Front end localization
+----------------------
+
+*   The Angular front end does localization according to the `Angular documentation <https://angular.io/guide/i18n>`_.
+*   The source language of the project is "en_US".
+*   The source strings end up in the file "src-ui/messages.xlf".
+*   The translated strings need to be placed in the "src-ui/src/locale/" folder.
+*   In order to extract added or changed strings from the source files, call ``ng xi18n --ivy``.
+
+Adding new languages requires adding the translated files in the "src-ui/src/locale/" fodler and adjusting a couple files.
+
+1.  Adjust "src-ui/angular.json":
+
+    .. code:: json
+
+        "i18n": {
+            "sourceLocale": "en-US",
+            "locales": {
+                "de": "src/locale/messages.de.xlf",
+                "nl-NL": "src/locale/messages.nl_NL.xlf",
+                "fr": "src/locale/messages.fr.xlf",
+                "en-GB": "src/locale/messages.en_GB.xlf",
+                "pt-BR": "src/locale/messages.pt_BR.xlf",
+                "language-code": "language-file"
+            }
+        }
+
+2.  Add the language to the available options in "src-ui/src/app/services/settings.service.ts":
+
+    .. code:: typescript
+
+        getLanguageOptions(): LanguageOption[] {
+            return [
+                {code: "en-us", name: $localize`English (US)`, englishName: "English (US)", dateInputFormat: "mm/dd/yyyy"},
+                {code: "en-gb", name: $localize`English (GB)`, englishName: "English (GB)", dateInputFormat: "dd/mm/yyyy"},
+                {code: "de", name: $localize`German`, englishName: "German", dateInputFormat: "dd.mm.yyyy"},
+                {code: "nl", name: $localize`Dutch`, englishName: "Dutch", dateInputFormat: "dd-mm-yyyy"},
+                {code: "fr", name: $localize`French`, englishName: "French", dateInputFormat: "dd/mm/yyyy"},
+                {code: "pt-br", name: $localize`Portuguese (Brazil)`, englishName: "Portuguese (Brazil)", dateInputFormat: "dd/mm/yyyy"}
+                // Add your new language here
+            ]
+        }
+    
+    ``dateInputFormat`` is a special string that defines the behavior of the date input fields and absolutely needs to contain "dd", "mm" and "yyyy".
+
+3.  Import and register the Angular data for this locale in "src-ui/src/app/app.module.ts":
+
+    .. code:: typescript
+
+        import localeDe from '@angular/common/locales/de';
+        registerLocaleData(localeDe)
+
+Back end localization
+---------------------
+
+A majority of the strings that appear in the back end appear only when the admin is used. However,
+some of these are still shown on the front end (such as error messages).
+
+*   The django application does localization according to the `django documentation <https://docs.djangoproject.com/en/3.1/topics/i18n/translation/>`_.
+*   The source language of the project is "en_US".
+*   Localization files end up in the folder "src/locale/".
+*   In order to extract strings from the application, call ``python3 manage.py makemessages -l en_US``. This is important after making changes to translatable strings.
+*   The message files need to be compiled for them to show up in the application. Call ``python3 manage.py compilemessages`` to do this. The generated files don't get
+    committed into git, since these are derived artifacts. The build pipeline takes care of executing this command.
+
+Adding new languages requires adding the translated files in the "src/locale/" folder and adjusting the file "src/paperless/settings.py" to include the new language:
+
+.. code:: python
+
+    LANGUAGES = [
+        ("en-us", _("English (US)")),
+        ("en-gb", _("English (GB)")),
+        ("de", _("German")),
+        ("nl-nl", _("Dutch")),
+        ("fr", _("French")),
+        ("pt-br", _("Portuguese (Brazil)")),
+        # Add language here.
+    ]
+
+
 Building the documentation
 ==========================