How request works in Play Framework 2? - json

Question

I've got to say I'm a little confused about how to handle request parameter using the new Play Framework 2. The data comes from different origins regarding how the request is made. So far, here's the possibilities :
1 - If you do a simple GET :
ctx().request().queryString()
2 - If you do a POST using an HTML Form :
The form :
<form method="post" action="/">
<input type="hidden" name="foo" value="bar" />
<input type="hidden" name="t" value="1" />
<input type="hidden" name="bool" value="true" />
<input type="submit" name="submit" value="Submit" />
</form>
The method :
public static Result test() {
ctx().request().queryString(); // {} ; As expected
ctx().request().body(); // contains data
ctx().request().body().asFormUrlEncoded(); // contains data
ctx().request().body().asJson(); // empty
return ok();
}
This seems normal.
Now if I add #BodyParser.Of(BodyParser.Json.class) (suppose I accept both Ajax POST and normal POST for fallback in Non-JS case) :
#BodyParser.Of(BodyParser.Json.class)
public static Result test() {
ctx().request().queryString(); // {} ; as Expected
ctx().request().body(); // contains data
ctx().request().body().asFormUrlEncoded(); // empty : Shouldn't this contains data since I posted them via a simple form ?!
ctx().request().body().asJson(); // empty
return ok();
}
And then, the hell hapened : How can I get the values of a simple form if none of them are filled (asJson, asFormUrlEncoded, etc) ?!
3 - If you do a POST via AJAX :
// Code in JS used :
$.ajax({
'url': '/',
'dataType': 'json',
'type': 'POST',
'data': {'foo': 'bar', 't': 1, 'bool': true}
});
Result :
public static Result test() {
ctx().request().queryString(); // {}
ctx().request().body(); // contains data
ctx().request().body().asFormUrlEncoded(); // contains data
ctx().request().body().asJson(); // empty
return ok();
}
With the #BodyParser.Of(BodyParser.Json.class) :
#BodyParser.Of(BodyParser.Json.class)
public static Result test() {
ctx().request().queryString(); // {}
ctx().request().body(); // contains data
ctx().request().body().asFormUrlEncoded(); // empty
ctx().request().body().asJson(); // empty : Shouldn't this contains data since I espect JSON ?!
return ok();
}
Here the inconsistencies is the asJson() method that should return the data since, according to the doc
Note: This way, a 400 HTTP response will be automatically returned for non JSON requests. (http://www.playframework.org/documentation/2.0/JavaJsonRequests)
What I'd like to know is what is the best decorator+method for a POST that would accept a simple post from HTML or an Ajax Request with POST?

Answer 1

I would recommend to use the Form classes provided by PlayFramework.
The Form will bind its values to the provided request data.
There are two different Form implementations:
DynamicForm: POST data is available through Map accessors methods
Form: the generic form of Form will map the POST data to an instance of an entity class [more information]
The form also provides some usefull features like automatic type conversion, validation, error reporting and so on.
a simple example with a dynamic form:
ajax request:
$.post("#routes.Application.movetodo()",
{ "id": 123, "destination": destination }, function(data)
{
// do something when request was successfull
});
Routes file:
GET / controllers.Application.index()
POST /movetodo controllers.Application.movetodo()
Controller implementation:
public static Result movetodo()
{
DynamicForm data = form().bindFromRequest(); // will read each parameter from post and provide their values through map accessor methods
// accessing a not defined parameter will result in null
String id = data.get("id");
String destination = data.get("destination");
return ok();
}

Answer 2

The reason that asJson() will be empty is that by default, $.ajax will send a request with a content type set to 'application/x-www-form-urlencoded; charset=UTF-8'. You need to set it to 'application/json; charset=utf-8':
$.ajax({
contentType: "application/json; charset=utf-8",
...
})