Today we are going to develop a simple play application using Scala.
To do so we must have sbt installed to our system.
Once installed we issue the command
sbt new playframework/play-scala-seed.g8
Then we are presented with an interactive terminal in order to pass valuable information.
name [play-scala-seed]: PlayStarter organization [com.example]: com.gkatzioura scala_version [2.11.8]: scalatestplusplay_version [2.0.0]: play_version [2.5.13]:
Then let us check what we have just created
cd playstarter sbt run
Navigate to http://localhost:9000 and you have a basic Play hello world.
By looking to our project structure, as expected, we have a directory with our controllers.
Consider our request being handled as an action. We issue a request and we receive an html view.
def index = Action { implicit request =>
Ok(views.html.index())
}
As you can see we the html that is rendered is located at the views directory. Play comes with Twirl as a template engine.
At conf/routes we can see how the route is configured to the index action
Let’s add a simple action to that controller that returns a text body.
def greet(name: String) = Action {
Ok("Hello " + name)
}
We have to edit the routes file to specify the new route and the get parameter
GET /greet controllers.HomeController.greet(name)
Then issue a request at http://localhost:9000/greet?john
On the next step we shall add a new route with a path param
Suppose we want to retrieve the total logins for a user.
We implement an action that send a fake number
def loginCount(userId: String) = Action {
Ok(14)
}
And then we register the route
GET /user/:userId/login/count controllers.HomeController.loginCount(userId)
By issuing the request http://localhost:9000/user/18/login/count
we shall receive the number 14.
To sum up we just implemented our first Play application. We also implemented some basic actions to our controller and achieved to pass some path and request parameters.
Emmanouil Gkatziouras 