Django return json and context data - javascript

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.

Related

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;
}

HttpClient PostAsync equivalent in JQuery with FormURLEncodedContent instead of JSON

I wrote a JQuery script to do a user login POST (tried to do what I have done with C# in the additional information section, see below).
After firing a POST with the JQuery code from my html page, I found the following problems:
1 - I debugged into the server side code, and I know that the POST is received by the server (in ValidateClientAuthentication() function, but not in GrantResourceOwnerCredentials() function).
2 - Also, on the server side, I could not find any sign of the username and password, that should have been posted with postdata. Whereas, with the user-side C# code, when I debugged into the server-side C# code, I could see those values in the context variable. I think, this is the whole source of problems.
3 - The JQuery code calls function getFail().
? - I would like to know, what is this JQuery code doing differently than the C# user side code below, and how do I fix it, so they do the same job?
(My guess: is that JSON.stringify and FormURLEncodedContent do something different)
JQuery/Javascript code:
function logIn() {
var postdata = JSON.stringify(
{
"username": document.getElementById("username").value,
"password": document.getElementById("password").value
});
try {
jQuery.ajax({
type: "POST",
url: "http://localhost:8080/Token",
cache: false,
data: postdata,
dataType: "json",
success: getSuccess,
error: getFail
});
} catch (e) {
alert('Error in logIn');
alert(e);
}
function getSuccess(data, textStatus, jqXHR) {
alert('getSuccess in logIn');
alert(data.Response);
};
function getFail(jqXHR, textStatus, errorThrown) {
alert('getFail in logIn');
alert(jqXHR.status); // prints 0
alert(textStatus); // prints error
alert(errorThrown); // prints empty
};
};
Server-side handling POST (C#):
public override async Task ValidateClientAuthentication(
OAuthValidateClientAuthenticationContext context)
{
// after this line, GrantResourceOwnerCredentials should be called, but it is not.
await Task.FromResult(context.Validated());
}
public override async Task GrantResourceOwnerCredentials(
OAuthGrantResourceOwnerCredentialsContext context)
{
var manager = context.OwinContext.GetUserManager<ApplicationUserManager>();
var user = await manager.FindAsync(context.UserName, context.Password);
if (user == null)
{
context.SetError(
"invalid_grant", "The user name or password is incorrect.");
context.Rejected();
return;
}
// Add claims associated with this user to the ClaimsIdentity object:
var identity = new ClaimsIdentity(context.Options.AuthenticationType);
foreach (var userClaim in user.Claims)
{
identity.AddClaim(new Claim(userClaim.ClaimType, userClaim.ClaimValue));
}
context.Validated(identity);
}
Additional information: In a C# client-side test application for my C# Owin web server, I have the following code to do the POST (works correctly):
User-side POST (C#):
//...
HttpResponseMessage response;
var pairs = new List<KeyValuePair<string, string>>
{
new KeyValuePair<string, string>( "grant_type", "password"),
new KeyValuePair<string, string>( "username", userName ),
new KeyValuePair<string, string> ( "password", password )
};
var content = new FormUrlEncodedContent(pairs);
using (var client = new HttpClient())
{
var tokenEndpoint = new Uri(new Uri(_hostUri), "Token"); //_hostUri = http://localhost:8080/Token
response = await client.PostAsync(tokenEndpoint, content);
}
//...
Unfortunately, dataType controls what jQuery expects the returned data to be, not what data is. To set the content type of the request data (data), you use contentType: "json" instead. (More in the documentation.)
var postdata = JSON.stringify(
{
"username": document.getElementById("username").value,
"password": document.getElementById("password").value
});
jQuery.ajax({
type: "POST",
url: "http://localhost:8080/Token",
cache: false,
data: postdata,
dataType: "json",
contentType: "json", // <=== Added
success: getSuccess,
error: getFail
});
If you weren't trying to send JSON, but instead wanted to send the usual URI-encoded form data, you wouldn't use JSON.stringify at all and would just give the object to jQuery's ajax directly; jQuery will then create the URI-encoded form.
try {
jQuery.ajax({
type: "POST",
url: "http://localhost:8080/Token",
cache: false,
data: {
"username": document.getElementById("username").value,
"password": document.getElementById("password").value
},
dataType: "json",
success: getSuccess,
error: getFail
});
// ...
To add to T.J.'s answer just a bit, another reason that sending JSON to the /token endpoint didn't work is simply that it does not support JSON.
Even if you set $.ajax's contentType option to application/json, like you would to send JSON data to MVC or Web API, /token won't accept that payload. It only supports form URLencoded pairs (e.g. username=dave&password=hunter2). $.ajax does that encoding for you automatically if you pass an object to its data option, like your postdata variable if it hadn't been JSON stringified.
Also, you must remember to include the grant_type=password parameter along with your request (as your PostAsync() code does). The /token endpoint will respond with an "invalid grant type" error otherwise, even if the username and password are actually correct.
You should use jquery's $.param to urlencode the data when sending the form data . AngularJs' $http method currently does not do this.
Like
var loginData = {
grant_type: 'password',
username: $scope.loginForm.email,
password: $scope.loginForm.password
};
$auth.submitLogin($.param(loginData))
.then(function (resp) {
alert("Login Success"); // handle success response
})
.catch(function (resp) {
alert("Login Failed"); // handle error response
});
Since angularjs 1.4 this is pretty trivial with the $httpParamSerializerJQLike:
.controller('myCtrl', function($http, $httpParamSerializerJQLike) {
$http({
method: 'POST',
url: baseUrl,
data: $httpParamSerializerJQLike({
"user":{
"email":"wahxxx#gmail.com",
"password":"123456"
}
}),
headers:
'Content-Type': 'application/x-www-form-urlencoded'
})
})

AJAX data contains one or more words..?

I'm using an AJAX post to submit form data and this is working well.
I'm not trying to show an message based on success or failure..
I've got this so far:
alert("Yehh.. Saving Data.");
$.ajax({
url:'go.php?doit=1',
data:$("form").serialize(),
type:'POST' })
.done(function(data) {
console.log(data);
})
When the submit completes data will contain either nothing or the text back from the update saying why it failed.
As an example I'd like to show an alert if there are no errors returned.
Any idea how I can do that?
If there are errors, I'd like to show an different alert.
I would return a response from the server in both cases, just to be safer...
but it will work if you don't, unless the server had a problem, no string was returned and you assumed you had a success! Do you see the problem here?
On the server:
Success:
$response = {
'status': 1,
'message': 'Success'
}
Error:
$response = {
'status': 0,
'message': 'Some error'
}
The Ajax function:
$.post( "go.php?doit=1",
{
data : $("form").serialize()
},
function(data) {
if(data.status == 1){
// success! Do something
}
else{
// error! Do something! eg: alert message
alert(data.message)
}
});
Assuming you mean that your HTTP request is sending, and that you are evaluating deliberate return values (for example you are validating your form, and returning an empty string to signify an error), you can do the following:
JS:
alert("Yehh.. Saving Data.");
$.ajax({
url: 'go.php?doit=1',
data: $("form").serialize(),
type: 'POST'
})
.done(function (data) {
if ( typeof data !== 'string' )
console.log("data is not a string. Consider 'return false' if this is unexpected?")
if ( data.length > 0 )
console.log("There was data returned")
if ( data.length === 0 )
console.log("Empty string returned!")
})
It might be a better idea to return a JSON object with the exact data you are trying to pass (such as a valid or fail flag, along with a message)

JSON pass null value to MVC 4 controller in IE9

I got some problem while posting JSON data into MVC 4 controller.
Below method is working fine in Firefox but unfortunately failed in IE 9
The JavaScript :
var newCustomer = {
CustName: $("#CustName").val(),
CustLocalName: $("#CustLocalName").val(),
CustNumber: $("#CustNumber").val(),
CountryID: $("#SelectCountry").val(),
City: $("#City").val()
};
$.ajax({
url: '#Url.Content("~/CustomerHeader/CreateCustomerHeader")',
cache: false,
type: "POST",
dataType: "json",
contentType: 'application/json; charset=utf-8',
data: JSON.stringify(newCustomer),
success: function (mydata) {
$("#message").html("Success");
},
error: function () {
$("#message").html("Save failed");
}
});
and this is my controller :
public JsonResult CreateCustomerHeader(CustomerHeader record)
{
try
{
if (!ModelState.IsValid)
{
return Json(new { Result = "ERROR", Message = "Form is not valid! Please correct it and try again." });
}
RepositoryHeader.Update(record);
return Json(new { Result = "OK", Record = record});
}
catch (Exception ex)
{
return Json(new { Result = "ERROR", Message = ex.Message });
}
}
the "data" variable as in public JsonResult CreateCustomerHeader(CustomerHeader **data**) is getting NULL but while using FireFox it holds the correct value.
UPDATE : New method trying using $.post
function CreateNewCustomer(newCustomer) {
$.post("/CustomerHeader/CreateCustomerHeader",
newCustomer,
function (response, status, jqxhr) {
console.log(response.toString())
});
}
Based off the bit that you've shown, this is a simplified variation that may work more consistently, using jQuery.post() (http://api.jquery.com/jQuery.post/):
var data = {
CustName: $("#CustName").val(),
CustLocalName: $("#CustLocalName").val(),
CustNumber: $("#CustNumber").val(),
CountryID: $("#SelectCountry").val(),
City: $("#City").val()
};
$.post({
'#Url.Action("CreateCustomerHeader", "CustomerHeader")',
data,
function(response, status, jqxhr){
// do something with the response data
}).success(function () {
$("#message").html("Success");
}).error(function () {
$("#message").html("Save failed");
});
$.post() uses $.ajax as it's base, but abstracts some of the details away. For instance, $.post calls are not cached, so you don't need to set the cache state (and setting it is ignored if you do). Using a simple JavaScript object lets jQuery decide how to serialize the POST variables; when using this format, I rarely have issues with the model binder not being able to properly bind to my .NET classes.
response is whatever you send back from the controller; in your case, a JSON object. status is a simple text value like success or error, and jqxhr is a jQuery XMLHttpRequest object, which you could use to get some more information about the request, but I rarely find a need for it.
first of all I would like to apologize #Tieson.T for not providing details on JavaScript section of the view. The problem is actually caused by $('#addCustomerHeaderModal').modal('hide') that occurred just after ajax call.
The full script :
try{ ..
var newCustomer =
{
CustName: $("#CustName").val(),
CustLocalName: $("#CustLocalName").val(),
CustNumber: $("#CustNumber").val(),
CountryID: $("#SelectCountry").val(),
City: $("#City").val()
};
$.ajax({
url: '/CustomerHeader/CreateCustomerHeader',
cache: false,
type: "POST",
dataType: "json",
data: JSON.stringify(newCustomer),
contentType: "application/json; charset=utf-8",
success: function (mydata) {
$("#message").html("Success");
},
error: function () {
$("#message").html("Save failed");
}
});
}
catch(Error) {
console.log(Error.toString());
}
//$('#addCustomerHeaderModal').modal('hide')//THIS is the part that causing controller cannot retrieve the data but happened only with IE!
I have commented $('#addCustomerHeaderModal').modal('hide') and now the value received by controller is no more NULL with IE. Don't know why modal-hide event behave like this with IE9.
Thanks for all the efforts in solving my problem guys :-)

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');
}
}
});

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