Play Framework: Controller action runs every load

Question

Does anyone know why my action runs every time I reload a page. I have a page with a button that should run when I click on it. But now it seems to run when I load the page.

Here is my button and javascript in file deliverables.scala.html

<input type="button" class="btn success" id="add" value="Export to Excel" onclick="JavaScript:generateExcelClick()" />

<script>
function generateExcelClick(event)
{
   window.location = "@Application.generateExcel(currentPage)";
}
</script>

And my controller:

public static void generateExcel(List<Infoobject> list) {
    ...creating a file (works)
    ...No return
}

How can I change this code so it only runs when I click on the button? The action should not render an another page or something like that. I only want to generate a file.

Thanks!

Edit

I've tried @controllers.Application.generateExcel(currentPage); and @Application.generateExcel(currentPage); in my Javascript function, but it's still creating the file even if I don't click the button.

I have also checked that @Application.generateExcel(currentPage); doesn't runs from an another site och function.

Someone, please?

Answer 1

A little explanation:

When writing in your Scala view and you say

@Application.generateExcel(currentPage)

It runs the function generateExcel in controller Application

What to do

You don't want it to run the function immediately. You want it to go there onClick

So use

@routes.Application.generateExcel(currentPage)

This outputs a link to that function

However for this to work there has to be a (GET) link to that function in your routes

Add this to routes

GET  /whatever/:thing                 controllers.Application.generateExcel(thing: List<path.InfoObject> list)

HOWEVER

This is a bad idea.Why? Because putting your entire list in a URL just isn't nice.

1. Do you ever see a complex list in a URL
2. URLs have to be less than 2000 characters

WHAT TO DO INSTEAD

Send the list as a POST data. Depending on how you take in your data you'll have to figure it out

Answer 2

If you are trying to just call a controller when clicking on a button, you could try :

<a href="@routes.YourController.YourMethod(args)"><button>Mybutton</button></a>

I don't think you need javascript here (if I understood your situation).

Edit: The idea of this answer is to say that the less javascript in your page, the better.

Edit2 : Can't comment the discussion below, so I put it here: As I said here : link , your have to declare your object like this :

controllers.Application.method(list : java.util.List[your.package.Infoobject])

Replace your.package with the package in which your object is (maybe models )

But you will get an errror : No QueryString binder found for type

This is because you can only put Strings and numerals in URLS, so the framework tells you to transform your Object (List) in a String (with the QueryStringBinder).

Answer 3

I would call routes-> /generateExcelReport from the button/link and make it return the file

How to send a file to browser for downloading?

How to download a file with Play Framework 2.0