Retrieve the message of an play.mvc.results.Error during a Ajax using the responseText

let's say i make a Play! ajax post using this jquery code, i need to show the error in a alert box.

$.ajax({
type: "post",
url: "@{removeQuoteToWatch()}",
dataType : "json",
data: {
    'symbol'        : symbol
 },
 error: function(xhr, ajaxOptions, thrownError){ 


            alert(xhr.responseText);
   },
  success: function(data){
            ...
   }
 });

the output in the alert box is the following :

{
type:   'play.mvc.results.Error',
message: 'Can't find symbol : Watch list is empty'
}

How can i only retrieve the message part?

i tryed something like

error: function(xhr, a开发者_高级运维jaxOptions, thrownError){ 


            alert(xhr.responseText.message);
        },

but it's not working

thanks,

As you can read here

http://api.jquery.com/jQuery.ajax/#jqXHR

the responseText is a string; if you want to parse it as json you could do

var res = $.parseJSON( xhr.responseText );
alert(res.message);

I personally do prefer not to throw a 500 error for logical issues, but use a normal 200 and provide the return-status and user-error in json.

the answer above is basically right BUT looking at it closer (and actually reproducing it) it appear that you have found a bug in the play framework. The framework should return

{ "type":"play.mvc.results.Error", "message":"Watchlistempty" }

while it does return:

{ type: 'play.mvc.results.Error', message: 'Watch list empty' }

which is not valid json.

I checked the play! lighthouse project and it does not seem to be reported before. I created a ticket at:

http://play.lighthouseapp.com/projects/57987-play-framework/tickets/1073-templateserror500json-returns-invalid-json#ticket-1073-2