如何使用Jquery ajax从Laravel输出json响应（发生错误时）

Question

I have no problem with the request and response process, Until I try to parse/process the json data returned from laravel when the error occurs.

I want to display a messsage error when the uploaded file is larger than the system accepts. My action is something like this:

...
if($_FILES['file1']['size'] > 0)
  {
    http_response_code(413);
    return Response()->json(["errorMsg" => "Your file is too large!"], 413);


  }
....

Client code:

  $.ajax({
                type: "POST",
                url: "/anuncio/realizar_upload_foto",
                 contentType: false,
                cache: false,
                dataType: "JSON",
               processData: false

...

...
    error: function (xh, jso) 

            {


                  alert(jso.errorMsg); //undefined here



                }

            });

Answer 1

In your way, you should find your data in xh.responseJSON.errorMsg

But you should follow REST Api practice.

First of all you should return json code 200 and pass your status message like.

return response()->json([
    "status" => "success",
    "data" => [....yourdata]
], 200);

in error case

return response()->json([
    "status" => "error",
    "msg" => "Your file is too large!"
], 4**);

Answer 2

According to the jQuery.ajax() document , the error callback accepts 3 parameters:

error

Type: Function( jqXHR jqXHR, String textStatus, String errorThrown )

The second parameter ( jso in your code) is just a String indicating status ( "error" for example). It does not contain any HTTP response body data.

To get errorMsg in the error callback, you need to use the first parameter ( jqXHR ). Example code would be:

error: function(jqXHR, status, error) {
  var errorObj = jqXHR.responseJSON; // This only works when dataType is defined as "JSON", or the "Content-Type" of HTTP response is "application/json". Otherwise, use the below general code.
  //var errorObj = JSON.parse(jqXHR.responseText);

  alert(errorObj.errorMsg);
}