Accessing HTTP Context in PlayFramework

Question

I'd like to create a global variable which all controllers can access. For this I've created a FrontController class which extends from Controller . All my usual controllers then extend from this FrontController .

Now I want to create a variable country in the FrontController which is set based on the host. And this information I try to get from the current request.

My question now is: How can I access the current HTTP Context?

package controllers;

import play.mvc.Controller;

public class FrontController extends Controller {

    // Country-Code of currenty country --> "ch", "de", "at"
    private String currentCountry;

    public FrontController() {
        this.init();
    }


    private void init() {
        this.initCountry();
    }


    private void initCountry() {

        String host = request().host();

        // then get country from host
    }
}

Because when I try this I get the error message:

Error injecting constructor, java.lang.RuntimeException: There is no HTTP Context available from here

I think the problem may be with the 'request()' call.

Answer 1

You can use an action to intercept the call to an specific / all methods in a controller and pass any necessary objects from the action to the controller .

Following is a quick action example:

public class FetchCountryAction extends play.mvc.Action.Simple {

    public CompletionStage<Result> call(Http.Context ctx) {
        String host = ctx.request().host();
        String country = getCountry(host);
        ctx.args.put("country", country);
        return delegate.call(ctx);
    }

}

And for the controller part:

@With(FetchCountryAction.class)
public static Result sampleAction() {
    String country = ctx().args.get("country");
    return ok();
}

Refer to the following link for more details on actions