Tutorial: Basic Localization and Nice Urls
Now we learn how to use nice urls and add localization to our project
Code
First we create our hello class little bit differently:
- class hello: public application {
- public:
- hello(worker_thread &worker) :
- application(worker)
- {
- url.add("^/(en|he)/?$",
- boost::bind(&hello::say_hello,this,_1));
- use_template("view");
- }
- void say_hello(string lang)
- {
- set_lang(lang);
- data::message c;
- c.message=gettext("Hello World");
- render("message",c);
- }
- };
Instead of overloading main() function, we use a url member of application class and add dispatchers according
to urls we need.
We bind to url that match regular expression: ^/(en|he)/?$ member function say_hello which receives first matched expression (en|he) as first parameter (using placeholder _1).
Then we implement say_hello(string) member function.
First of all, we define our locale by calling set_lang(lang). and then set value of c.message using gettext().
Note: CppCMS gettext implementation is thread safe, thus you can set different languages in different threads.
Template
Now we change our template, and use following code:
- <html>
- <head>
- <meta http-equiv="Content-Type" content="text/html; charset=utf-8" >
- </head>
- <% if rtl %>
- <body dir="rtl">
- <% else %>
- <body>
- <% end %>
- <h1><% gt "We want to say" %></h1>
- <p><% message %></p>
- </body>
- <html>
First, we added utf-8 charset and then we have two important localization functions:
<% if rtl %>is condition that checks if language is written right-to-left, like Hebrew or Arabic.- Instead of writing directly "We want to say" we use command
<% gt "We want to say" %>, defined that quoted text becomes translated to the target language when template is rendered.
Translation
Now when we build template code we add gettext domain name for our application using -d hello:
- cppcms_tmpl_cc -d hello view.tmpl -o view.cpp
Now when C++ source code is build we can extract messages from them calling
- xgettext view.cpp hello.cpp
And translate them.
There is an important part in messages.po:
- msgid "LTR"
- msgstr ""
It should be translated as RTL for languages like Hebrew or Arabic -- right-to-left languages.
After complete translation, we can create standard
gettext directory locale/he/LC_MESSAGES and put there
our hello.mo.
Configuration and Running
In order to enable gettext support in our application we should add following lines to our config.txt
- locale.dir = "./locale"
- locale.lang_list = { "he" "en" }
- locale.domain_list = { "hello" }
Specifying location of "locale" directory, the list of supported languages and list of supported domains.
Now we can run our application
- cppcms_run hello.fcgi -c config.txt
We can go to localhost:8080/hello.fcgi/en and see our "Hello World".
We can make urls nicer by adding -s parameter --- the script path.
- cppcms_run -s /hello hello.fcgi -c config.txt
And now we can visit localhost:8080/hello/en or localhost:8080/hello/he
