How do I handle exceptions thrown in a controller when jquery ajax calls an action?
For example, I would like a global javascript code that gets executed on any kind of server exception during an ajax call which displays the exception message if in debug mode or just a normal error message.
On the client side, I will call a function on the ajax error.
On the server side, Do I need to write a custom actionfilter?
If the server sends some status code different than 200, the error callback is executed:
$.ajax({
url: '/foo',
success: function(result) {
alert('yeap');
},
error: function(XMLHttpRequest, textStatus, errorThrown) {
alert('oops, something bad happened');
}
});
and to register a global error handler you could use the $.ajaxSetup()
method:
$.ajaxSetup({
error: function(XMLHttpRequest, textStatus, errorThrown) {
alert('oops, something bad happened');
}
});
Another way is to use JSON. So you could write a custom action filter on the server which catches exception and transforms them into JSON response:
public class MyErrorHandlerAttribute : FilterAttribute, IExceptionFilter
{
public void OnException(ExceptionContext filterContext)
{
filterContext.ExceptionHandled = true;
filterContext.Result = new JsonResult
{
Data = new { success = false, error = filterContext.Exception.ToString() },
JsonRequestBehavior = JsonRequestBehavior.AllowGet
};
}
}
and then decorate your controller action with this attribute:
[MyErrorHandler]
public ActionResult Foo(string id)
{
if (string.IsNullOrEmpty(id))
{
throw new Exception("oh no");
}
return Json(new { success = true });
}
and finally invoke it:
$.getJSON('/home/foo', { id: null }, function (result) {
if (!result.success) {
alert(result.error);
} else {
// handle the success
}
});