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JQuery confirmation dialog after AJAX request

I need to validate, on server side, if a person with a given registration number is already on the database. If this person is already registered, then I proceed with the program flow normally. But, if the number is not already registered, then I'd like to show a confirmation dialog asking if the operator wants to register a new person with the number entered and, if the operator answers yes, then the person will be registered with the number informed on the form on it's submission.
I've tried
Server side(PHP):
if (!$exists_person) {
$resp['success'] = false;
$resp['msg'] = 'Do you want to register a new person?';
echo json_encode($resp);
}
Client side:
function submit(){
var data = $('#myForm').serialize();
$.ajax({
type: 'POST'
,dataType: 'json'
,url: 'myPHP.php'
,async: 'true'
,data: data
,error: function(response){
alert('response');
}
});
return false;
}
I can't even see the alert, that's where I wanted to put my confirmation dialog, with the message written on server side. Other problem, how do I resubmit the entire form appended with the operator's answer, so the server can check if the answer was yes to register this new person?
EDIT
I was able to solve the problem this way:
Server side(PHP):
$person = find($_POST['regNo']);
if ($_POST['register_new'] === 'false' && !$person) {
$resp['exists'] = false;
$resp['msg'] = 'Do you want to register a new person?';
die(json_encode($resp)); //send response to AJAX request on the client side
} else if ($_POST['register_new'] === 'true' && !$person) {
//register new person
$person = find($_POST['regNo']);
}
if($person){
//proceed normal program flow
}
Client side:
function submit(e) {
e.preventDefault();
var data = $('#myForm').serialize();
var ajax1 = $.ajax({
type: 'POST'
, dataType: 'json'
, async: 'true'
, url: 'myPHP.php'
, data: data
, success: function (response) {
if (!response.exists && confirm(response.msg)) {
document.getElementById('register_new').value = 'true'; //hidden input
dados = $('#myForm').serialize(); //reserialize with new data
var ajax2 = $.ajax({
type: 'POST'
, dataType: 'json'
, async: 'true'
, url: 'myPHP.php'
, data: data
, success: function () {
document.getElementById('register_new').value = 'false';
$('#myForm').unbind('submit').submit();
}
});
} else if (response.success) {
alert(response.msg);
$('#myForm').unbind('submit').submit();
}
}
});
}

There doesn't appear to be anything wrong with your PHP.
The problem is (1) You are doing the alert inside of an error callback, and your request isn't failing, so you don't see the alert. (2) You are alerting the string 'response' instead of the variable response.
It is also worth noting that you should be using the .done() and .fail() promise methods (http://api.jquery.com/jquery.ajax/#jqXHR).
Here is the fixed JS:
function submit() {
var data = $('#myForm').serialize();
// Same as before, with the error callback removed
var myAjaxRequest = $.ajax({
type: 'POST',
dataType: 'json',
url: 'myPHP.php',
async: 'true',
data: data
});
// The request was successful (200)
myAjaxRequest.done(function(data, textStatus, jqXHR) {
// The data variable will contain your JSON from the server
console.log(data);
// Use a confirmation dialog to ask the user your question
// sent from the server
if (confirm(data.msg)) {
// Perform another AJAX request
}
});
// The request failed (40X)
myAjaxRequest.fail(function(jqXHR, textStatus, errorThrown) {
console.log(errorThrown);
});
return false;
}
Also, you are setting a 'status' in PHP and checking that in the JS (I presume). What you want to be doing is setting a HTTP status code from the server, as below:
if (!$exists_person)
{
$resp['msg'] = 'Do you want to register a new person?';
// 400 - Bad Request
http_response_code(400);
echo json_enconde($resp);
}
Then, jQuery will determine whether the request failed based on the status code you respond with. 200 is a successful request, and 400 numbers are fail.
Check out this page for a full list: https://httpstatuses.com/

Okay so this is a two part question; I'll try my best to answer both parts:
Part 1: How to detect if success is false and trigger the confirmation popup?
In jQuery.ajax the error handler is triggered based on response code. This is probably not what you want. You can use your success handler and test the value res.success to see if it's true or false. It would be something along the lines of:
function submit(e) {
e.preventDefault();
var data = $('#myForm').serialize();
$.ajax({
type: 'POST',
dataType: 'json',
url: 'myPHP.php',
async: 'true',
data: data
}).done(function(res) {
if (!res.success) {
alert(res.msg);
}
});
}
Part 2: How do I resubmit with a confirmation?
Working off of our previous code we will make some changes that allow for submit() to be passed an argument registerNew. If registerNew is true we will pass it as a param to the ajax handler in the PHP so it knows we want to register a new person. The Javascript will look something like this:
function submit(e, registerNew) {
if (e) e.preventDefault();
var data = $('#myForm').serialize();
var ajax_options = {
type: 'POST',
dataType: 'json',
url: 'myPHP.php',
async: 'true',
data: data
};
ajax_options.data.register_new = !!registerNew;
$.ajax(ajax_options).done(function(res) {
if (!res.success && confirm(res.msg)) {
submit(null, true);
}
});
}
As you can see here, we are passing a new register_new param in the data in our ajax options. Now we need to detect this on the PHP side, which is easy enough and looks like this (this goes in your php ajax handler):
if ($_POST["register_new"]) {
// new user registration code goes here
} else {
// your existing ajax handler code
}

Add confirm inside submit function
function submit(){
var data = $('#myForm').serialize();
if (confirm('Are you ready?')) {
$.ajax({
type: 'POST'
,dataType: 'json'
,url: 'myPHP.php'
,async: 'true'
,data: data
,error: function(response){
alert('response');
}
});
}
return false;
}

Django return json and context data

I have a form that its processed with ajax and I need to get a return from the view, since I make some validations. The call to the view works fine but if I try to get a response from the view to the javascript (json) I loose the context data.
This is my ajax call that works just fine ( returns 202 OK ), but if data.valid == false, the message is shown but without the context data in the template.
$.ajax({
type: "POST",
url: '/validate_create/',
contentType: 'application/x-www-form-urlencoded;charset=utf-8',
csrfmiddlewaretoken: $('input[name=csrfmiddlewaretoken]').val(),
data: frmData,
dataType: "json",
success: function(data)
{
if (data.valid== true){
alert ('validation ok');
}else{
alert ('validation error');
}
},
error: function (data) {
alert('err');
}
});
This is my original return from the view ( without returning any data ):
return render_to_response('shop/checkout.html', ctx, context_instance=RequestContext(request))
And after checking other posts I did this but doesnt return the context (cart in this case in session)
context = {}
context['data'] = render_to_string("shop/checkout.html", {'cart': cart,'valid':valid})
return HttpResponse(json.dumps(context), content_type = "application/json")
UPDATE: the code above was ok, and the ajax received the response with the json. I had something wrong with the view causing the session to be deleted.
By the way, in the ajax call data.valid works fine in the condition but if I console.log is undefined.

How to handle response of a POST request in jQuery

I am trying to POST some data to my ASP.Net MVC Web API controller and trying to get it back in the response. I have the following script for the post:
$('#recordUser').click(function () {
$.ajax({
type: 'POST',
url: 'api/RecordUser',
data: $("#recordUserForm").serialize(),
dataType: 'json',
success: function (useremail) {
console.log(useremail);
},
error: function (xhr, status, err) {
},
complete: function (xhr, status) {
if (status === 'error' || !xhr.responseText) {
alert("Error");
}
else {
var data = xhr.responseText;
alert(data);
//...
}
}
});
});
The problem with this script is that whenever I try to post the data, the jQuery comes back in "error" instead of "success".
I have made sure that there is no problem with my controller. I can get into my api method in debug mode whenever the request is made and can see that it is getting the data from the POST request and is returning it back. This controller is quite simple:
public class RecordUserController : ApiController
{
public RecordUserEmailDTO Post(RecordUserEmailDTO userEmail)
{
return userEmail;
}
}
I am not sure how I can get jQuery to print out any useful error messages. Currently when I try to debug the jQuery code using Chrome console it shows an empty xhr.responseText, nothing in "err" object and "status" set to "error" which as you see is not quite helpful.
One more thing that I have tried is to run the following code directly from the console:
$.ajax({
type: 'POST',
url: 'api/RecordUser',
data: {"Email":"email#address.com"},
dataType: 'json',
success: function (useremail) {
console.log(useremail);
},
error: function (xhr, status, err) {
console.log(xhr);
console.log(err);
console.log(status);
alert(err.Message);
},
complete: function (xhr, status) {
if (status === 'error' || !xhr.responseText) {
alert("Error");
}
else {
var data = xhr.responseText;
alert(data);
}
}
});
i.e. using the same script without actually clicking on the button and submitting the form. Surprisingly, this comes back with the right response and I can see my data printed out in console. For me this atleast means that my Web API controller is working fine but leaves me with no clue as to why it is not working on clicking the button or submitting the form and goes into "error" instead of "success".
I have failed to find any errors in my approach and would be glad if someone could help me in getting a response back when the form is posted.

As suggested by Alnitak, I was using complete callback along with success and error ones. Removing complete from my code fixed the issue.
Thanks to Alnitak.

jQuery AJAX and handling different dataTypes

I'm using ASP.Net MVC, but this applies to any framework.
I'm making an Ajax call to my server, which most of the time returns plain old HTML, however if there is an error, I'd like it to return a JSON object with a status message (and a few other things). There doesn't appear to be a way for the dataType option in the jQuery call to handle this well. By default it seems to parse everything as html, leading to a <div> being populated with "{ status: 'error', message: 'something bad happened'}".
[Edit] Ignoring the dataType object and letting jQuery figure out doesn't work either. It views the type of the result as a string and treats it as HTML.
One solution I came up with is to attempt to parse the result object as JSON. If that works we know it's a JSON object. If it throws an exception, it's HTML:
$.ajax({
data: {},
success: function(data, textStatus) {
try {
var errorObj = JSON.parse(data);
handleError(errorObj);
} catch(ex) {
$('#results').html(data);
}
},
dataType: 'html', // sometimes it is 'json' :-/
url: '/home/AjaxTest',
type: 'POST'
});
However, using an Exception in that way strikes me as pretty bad design (and unintuitive to say the least). Is there a better way? I thought of wrapping the entire response in a JSON object, but in this circumstance, I don't think that's an option.
Here's the solution that I got from Steve Willcock:
// ASP.NET MVC Action:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult AjaxTest(int magic) {
try {
var someVal = GetValue();
return PartialView("DataPage", someVal);
} catch (Exception ex) {
this.HttpContext.Response.StatusCode = 500;
return Json(new { status = "Error", message = ex.Message });
}
}
// jQuery call:
$.ajax({
data: {},
success: function(data, textStatus) {
$('#results').html(data);
},
error: function() {
var errorObj = JSON.parse(XMLHttpRequest.responseText);
handleError(errorObj);
},
dataType: 'html',
url: '/home/AjaxTest',
type: 'POST'
});

For your JSON errors you could return a 500 status code from the server rather than a 200. Then the jquery client code can use the error: handler on the $.ajax function for error handling. On a 500 response you can parse the JSON error object from the responseText, on a 200 response you can just bung your HTML in a div as normal.

While Steve's idea is a good one, I'm adding this in for completeness.
It appears that if you specify a dataType of json but return HTML, jQuery handles it fine.
I tested this theory with the following code:
if($_GET['type'] == 'json') {
header('Content-type: application/json');
print '{"test":"hi"}';
exit;
} else {
header('Content-type: text/html');
print '<html><body><b>Test</b></body></html>';
exit;
}
The $_GET['type'] is just so I can control what to return while testing. In your situation you'd return one or the other depending on whether things went right or wrong. Past that, with this jQuery code:
$.ajax({
url: 'php.php?type=html', // return HTML in this test
dataType: 'json',
success: function(d) {
console.log(typeof d); // 'xml'
}
});
Even though we specified JSON as the dataType, jQuery (1.3.2) figures out that its not that.
$.ajax({
url: 'php.php?type=json',
dataType: 'json',
success: function(d) {
console.log(typeof d); // 'object'
}
});
So you could take advantage of this (as far as I know) undocumented behavior to do what you want.

But why not return only JSON regardless of the status (success or error) on the POST and the use a GET to display the results? It seems like a better approach if you ask me.

Or you could always return a JSON response, and have one parameter as the HTML content.
Something like:
{
"success" : true,
"errormessage" : "",
"html" : "<div>blah</div>",
}
I think you'd only have to escape double quotes in the html value, and the json parser would undo that for you.

I ran into this exact same issue with MVC/Ajax/JQuery and wanting to use multiple dataTypes (JSON and HTML). I have a AJAX request to uses an HTML dataType to return the data, but I attempt convert the data that comes back from the ajax request to a JSON object. I have a function like this that I call from my success callback:
_tryParseJson: function (data) {
var jsonObject;
try {
jsonObject = jQuery.parseJSON(data);
}
catch (err) {
}
return jsonObject;
}
I then assume that if the jsonObject and errorMessage property exist, that an error occured, otherwise an error did not occur.

I accomplished this by using the ajax success and error callbacks only. This way I can have mixed strings and json objects responses from the server.
Below I'm prepared to accept json, but if I get a status of "parsererror" (meaning jquery couldn't parse the incoming code as json since that's what I was expecting), but it got a request status of "OK" (200), then I handle the response as a string. Any thing other than a "parsererror" and "OK", I handle as an error.
$.ajax({
dataType: 'json',
url: '/ajax/test',
success: function (resp) {
// your response json object, see if status was set to error
if (resp.status == 'error') {
// log the detail error for the dev, and show the user a fail
console.log(resp);
$('#results').html('error occurred');
}
// you could handle other cases here
// or use a switch statement on the status value
},
error: function(request, status, error) {
// if json parse error and a 200 response, we expect this is our string
if(status == "parsererror" && request.statusText == "OK") {
$('#results').html(request.responseText);
} else {
// again an error, but now more detailed and not a parser error
// and we'll log for dev and show the user a fail
console.log(status + ": " + error.message);
$('#results').html('error occurred');
}
}
});

Can I evaluate the response type of an $.ajax() call in success callback?

I am using jQuery to make an AJAX request to a remote endpoint. That endpoint will return a JSON object if there is a failure and that object will describe the failure. If the request is successful it will return HTML or XML.
I see how to define the expected request type in jQuery as part of the $.ajax() call. Is there a way to detect the request type in the success handler?
$.ajax(
{
type: "DELETE",
url: "/SomeEndpoint",
//dataType: "html",
data:
{
"Param2": param0val,
"Param1": param1val
},
success: function(data) {
//data could be JSON or XML/HTML
},
error: function(res, textStatus, errorThrown) {
alert('failed... :(');
}
}
);

Have you application generate correct Content-Type headers (application/json, text/xml, etc) and handle those in your success callback. Maybe something like this will work?
xhr = $.ajax(
{
//SNIP
success: function(data) {
var ct = xhr.getResponseHeader('Content-Type');
if (ct == 'application/json') {
//deserialize as JSON and continue
} else if (ct == 'text/xml') {
//deserialize as XML and continue
}
},
//SNIP
);
Untested, but it's worth a shot.

how about using the complete option?
$.ajax({
...
complete : function(xhr, status) {
// status is either "success" or "error"
// complete is fired after success or error functions
// xhr is the xhr object itself
var header = xhr.getResponseHeader('Content-Type');
},
...
});

By the time it calls your success handler, the data has already been deserialized for you. You need to always return the same data type for any successful result. If there truly is an error, you should probably throw an exception and let it get handled by the error callback instead. This should be able to parse the resulting error and package it for your callback, that is, it will detect that the response did not have 200 OK status and parse the result to obtain the error information.