= [wiki:GenshiTutorial Genshi Tutorial]: Adding Internationalization =

To internationalize our application we'll use [http://babel.edgewall.org Babel].
{{{
easy_install Babel
}}}

To get the basic info on how to work with message catalog using Babel [http://babel.edgewall.org/wiki/Documentation/0.9/messages.html read this], I'll just follow you through the basic procedures.

First we'll create a `locale` directory under `geddit` which will hold the message catalogs. Next, we'll create a mapping file which will tell Babel how to handle the several type of files. Create a `mappings.cfg` on the directory above the geddit one and add inside:
{{{
# Extraction from Python source files

[python: **.py]

# Extraction from Genshi HTML and text templates

[genshi: **/templates/**.html]
}}}
The above will tell Babel that `.py` files should be handled by the python extractor and that the `.html` files should be handled by the Genshi extractor.

Now let's extract some messages to be translated:
{{{
pybabel extract -o geddit/locale/geddit.pot -F ./mappings.cfg geddit
}}}

The output should be similar to:
{{{
extracting messages from geddit/__init__.py
extracting messages from geddit/controller.py
extracting messages from geddit/form.py
extracting messages from geddit/model.py
extracting messages from geddit/translator.py
extracting messages from geddit/lib/__init__.py
extracting messages from geddit/lib/ajax.py
extracting messages from geddit/lib/template.py
extracting messages from geddit/templates/_comment.html
extracting messages from geddit/templates/_form.html
extracting messages from geddit/templates/comment.html
extracting messages from geddit/templates/index.html
extracting messages from geddit/templates/info.html
extracting messages from geddit/templates/layout.html
extracting messages from geddit/templates/submit.html
writing PO template file to geddit/locale/geddit.pot
}}}

Now let's create the English catalog which normally isn't translated:
{{{
pybabel init -D geddit -i geddit/locale/geddit.pot -d geddit/locale/ -l en
}}}

And, since I'm Portuguese, we'll create a Portuguese catalog to serve as an example:
{{{
pybabel init -D geddit -i geddit/locale/geddit.pot -d geddit/locale/ -l pt_PT
}}}
On this step you can create a catalog in your mother language if not english so that you can see Geddit translated.

Edit the contents of the resulting `geddit.po` for the locale you created, translate it, save and exit.

Next step will involve compiling these catalogs so that they can be used by python's gettext module:
{{{
pybabel compile -D geddit -d geddit/locale/ -f --statistics
}}}

Now, our Geddit application needs to use and know how to use these translated catalogs.

Let's modify `geddit/controller.py` with(this is a diff):
{{{
#!diff
Index: geddit/controller.py
===================================================================
--- geddit/controller.py        (revision 766)
+++ geddit/controller.py        (working copy)
@@ -92,8 +92,40 @@
             links = sorted(self.data.values(), key=operator.attrgetter('time'))
             return template.render(links=links)

+    @cherrypy.expose
+    def set_lang(self, language):
+       import gettext
+       import formencode
+       import __builtin__
+       locale_dir = os.path.join(os.path.dirname(__file__), 'locale')
+       domain = 'geddit'
+       codeset= 'utf-8'
+
+       gettext.bindtextdomain(domain, locale_dir)
+       gettext.textdomain(domain)
+
+       try:
+            translator = gettext.translation(domain,
+                                         locale_dir,
+                                         languages=[language],
+                                         codeset=codeset)
+       except IOError, error:
+            language=['en']
+            translator = gettext.translation(domain,
+                                         locale_dir,
+                                         languages=language,
+                                         codeset=codeset)
+       formencode.api.set_stdtranslation(languages=[language])
+       __builtin__._ = translator.ugettext
+       raise cherrypy.HTTPRedirect('/')
+
+

 def main(filename):
+    import __builtin__
+    from gettext import NullTranslations
+
+    __builtin__._ = NullTranslations().ugettext
     # load data from the pickle file, or initialize it to an empty list
     if os.path.exists(filename):
         fileobj = open(filename, 'rb')
}}}

Our `geddit/lib/template.py` with(also diff):
{{{
#!diff
Index: geddit/lib/template.py
===================================================================
--- geddit/lib/template.py      (revision 766)
+++ geddit/lib/template.py      (working copy)
@@ -4,6 +4,7 @@
 from genshi.core import Stream
 from genshi.output import encode, get_serializer
 from genshi.template import Context, TemplateLoader
+from genshi.filters import Translator

 from geddit.lib import ajax

@@ -42,6 +43,7 @@
         template = loader.load(args[0])
     else:
         template = cherrypy.thread_data.template
+    template.filters.insert(0, Translator(_))
     ctxt = Context(url=cherrypy.url)
     ctxt.push(kwargs)
     return template.generate(ctxt)
}}}

 '''WARNING''': there's an error in the above code, please see #238.

And finaly our `geddit/templates/layout.html` with(also diff):
{{{
#!diff
Index: geddit/templates/layout.html
===================================================================
--- geddit/templates/layout.html        (revision 766)
+++ geddit/templates/layout.html        (working copy)
@@ -19,6 +19,16 @@
         <a href="/"><img src="${url('/media/logo.gif')}" width="201" height="79" alt="geddit?" /></a>
       </div>
       <div id="content">
+        <form method="post" id="lang_choose" name="lang_choose" action="${url('/set_lang')}">
+        <label for="language">Language:</label>
+        <select id="language" name="language" onChange="$('#lang_choose').submit()">
+          <option value="en">English</option>
+          <option value="pt_PT">Portuguese</option>
+        </select>
+        </form>
+        <noscript>
+          <input type="submit" name="submit" value="Update"/>
+        </noscript>
         ${select('*|text()')}
       </div>
       <div id="footer">
}}}

This will allow the user to select the language.
[[Image(tutorial07.png)]]

And that wraps it up!