Play Framework 2.5 - Using "@" when generating html code in controller (html.apply)

Question

In the controller we are creating a string which shall be interpreted as Html when the page is being rendered. Whenever the string contains scala/twirl code starting with "@" it leads to the page not rendering it correctly/at all.

Controller:

// render method
return ok(Html.apply(testButton()), testForm);

public String testButton() throws SQLException {
    result = "<input type='radio' id='@TestForm(\"TestID\").id'   
    name='@TestForm(\"TestID\").name'  value='5'  >" + "Test"; 
    return result;
}

Scala.html:

@(buttons: Html)(TestForm: Form[TestForm])

@buttons

How it should look:

<input type='radio' id='TestID' name='TestID'  value=5  >test

How it looks:

<input type='radio' id='@TestForm("TestID").id' name='@TestForm("TestID").name'  value='5'  >test

We also tested this with other examples. The problem really seems to be the @. Maybe the parser parses the site once, replaces the @button with our code, but doesn't parse that after it. We also tried escaping the @ with different methods(@@, \@, no @), but it always ended up in plain text afterwards.

What is the easiest method to get an @ inside another @ to render?

Why don't you want to create reusable view for button instead of creating (I would say clumsy) string? — Rumid
– Rumid, Commented Mar 6, 2017 at 13:06

Michael Zajac · Accepted Answer · 2017-03-06 16:02:07Z

3

You can't do this from within a controller. @ is parsed by the Twirl compiler at compile-time, but you're trying to introduce it at run-time. It will never work. Even if you could get it to work, it wouldn't be a good idea. It breaks the MVC paradigm by muddling the controller code with presentation code.

This should be another Twirl view that looks something like:

// I don't know what TestForm is, so this is a guess
// that it exists in the controller and needs to be passed in
@(TestForm: Form) 

<input
  type='radio'
  id='@TestForm("TestID").id'   
  name='@TestForm("TestID").name'  value='5'  
>

answered Mar 6, 2017 at 16:02

Michael Zajac

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2 Comments

Favehawk Over a year ago

thanks for the insight. but how are we supposed to call this view a flexible amount of times with flexible values ?

Michael Zajac Over a year ago

What does that mean? A Form is a very general object.

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