ajax can not receive JSON from php

Question

I have issues with receiving a JSON object from PHP. I can alert it and get a ( I think correct) JSON Object with dataType: 'text', but not use it like data.message --> it is "undefined". With dataType: 'json','jsonp' or the ajax call $.getJSON it does not work (It does not fire this request).

AJAX

$('#login').click(function () {
var name = $('#username').val();
var pass = $('#password').val();
$.ajax({
    url: "http://localhost/weltenbummler/Weltenbummler1/Weltenbummler1/app/login.php?username=" + name + "&password=" + pass,
    dataType: 'text',
    type: 'GET',
    success: function (d) {
        alert(d);
        alert(d.message);
    }
});});

Alerted JSONs

{"status":"f","message":"Benutzername und Passwort stimmen nicht ueberein"} or

{"status":"t","message":"Erfolgreich eingeloggt!","data":{"id":"1","mail":"abc","password":"123"}}

I tested the received String on jsonlint.com and it should be valid. I tried to JSON.parse(data) , $.parseJSON(data) what does not work. JSON.stringify(data) is returning the JSON with slashes (I do not know why).

Postman can read it as well in HTML, text, XML or JSON...

In php I tried to change the header to header("Content-type: application/json; charset=utf-8"); or to force the response as JSON.

connect.php file:

<?php
$host = "127.0.0.1";
$user= "root";
$pw="";
$db = "weltenbummler";

//Create connection
$con = new mysqli($host,$user,$pw,$db);


//Check connection
if($con->connect_error){
    die("Connection failed: " .$con->connect_error);
}?>

login.php file:

<?php
header('Content-type: application/json');
require 'connect.php';

$username = $_GET['username'];
$password = $_GET['password'];

$response = array();
if(empty($username)){
    $response = array(
        "status " => " f",
        "message " => " Gebe einen Benutzernamen ein!"
    );
    die(json_encode($response));
}
if(empty($password)){
    $response = array(
        "status" => "f",
        "message"=> "Gebe ein Passwort ein!"
    );
    die(json_encode($response));
}

$sqlstatement= ("SELECT id,mail,password FROM user WHERE mail = '$username' AND password = '$password'");
$result = mysqli_fetch_assoc($con->query($sqlstatement));

if (!$result) {
    $response = array(
        "status" => "f",
        "message" => "Benutzername und Passwort stimmen nicht ueberein"
    );
} else {
    $response = array(
        "status" => "t",
        "message" => "Erfolgreich eingeloggt!",
        "data" => $result
    );
}
$con->close();

echo json_encode($response);?>

EDIT 1:

As soon as I use dataType: 'json' I receive nothing (not even the string), so I continue using 'text'. Does my PHP file need a change to receive JSON?

Here are the things I tried the comments:

console.log(typeof d); returns string

alert(JSON.stringify(d)); returns "{\"status\":\"f\",\"message\":\"Benutzername und Passwort stimmen nicht ueberein\"}"

alert(JSON.parse(d)); returns Uncaught SyntaxError: Unexpected token in JSON at position 0

Any more recommendations? Thank you!

If `JSON.parse(data)` does not work and `JSON.stringify(data)` returns the data with additional slashes then this indicates that you might have some characters (e.g. Invisible ones) that might make the json invalid. What error do you get for `console.dir(JSON.parse(data))`, how does the output of `console.log(JSON.stringify(data))` look like? — t.niese, Aug 15 '17 at 04:59
try moving $con->close(); before echo and try console.log(typeof d); — Ye Lwin Soe, Aug 15 '17 at 07:25

score 1 · Answer 1 · answered Aug 15 '17 at 04:48

1

Try this

$.ajax({
    url: 'http://localhost/weltenbummler/Weltenbummler1/Weltenbummler1/app/login.php?username=' + name + '&password=' + pass,
    dataType: 'json',
    type: 'get',
    success: function (e) {
        alert( JSON.parse(e.message) ); // undefined
    }
});

answered Aug 15 '17 at 04:48

Juliver Galleto

7,927
19
69
138

For the data shown in the question `e.message` is a text and not JSON, why should the OP try to parse that? If the retruned data is correctly recognized as JSON then `e` would alread hold the parsed object. – t.niese Aug 15 '17 at 05:04
if datatype is text, he could just do "alert(e)", op said, its json, so he/she needs to parse in order to transform the return data unto a proper javascript objects. – Juliver Galleto Aug 15 '17 at 06:34
Yes but the OP says that `alert(d);` shows the JSON string, and `alert(d.message);` shows `undefined`. So if `dataType: 'json'` would correct the problem that the returned data is not parsed by jQuery, then `JSON.parse(e.message)` would try to parse the `"Benutzername und Passwort stimmen nicht ueberein"` which is not JSON. If it would not solve the problem, the `d.message` would still be `undefined` and `JSON.parse(e.message)` would show an error because of parsing `undefined`. – t.niese Aug 15 '17 at 07:27
sadly this did not work...as soon as I change the dataType to "json" I recieve nothing, not even the string anymore. with "text" i get the string but the alert of '( JSON.parse(e.message) );' //nothing happens – Leonard Traeger Aug 19 '17 at 00:37

score 0 · Answer 2 · answered Aug 19 '17 at 03:00

You can read out the exact recieved data with chrome developer: 1. I recieved a string with hidden variables: #$63434;{"status":false,...} and with 2. With PHP errors aswell

To 1.: PHP buffering variables fireing your code --> scope it with ob_start(); and ob_end_clean(); reference: https://stackoverflow.com/a/9985307/8036245

To 2.: Just fix your php code: I had the issue, that not defined variables alert missing reference

After that I could even fire the $.getJSON(..) call! Hope this will help somone :)

score -1 · Answer 3 · answered Aug 15 '17 at 04:48

contentType is the header sent to the server, specifying a particular format. Example: I'm sending json or XML
dataType is you telling jQuery what kind of response to expect. Expecting JSON, or XML, or HTML, etc....the default it for jQuery to try and figure it out.

The $.ajax() documentation has full descriptions of these as well.

$.ajax({
    url: "http://localhost/weltenbummler/Weltenbummler1/Weltenbummler1/app/login.php?username=" + name + "&password=" + pass,
    dataType: 'JSON',
    type: 'GET',
    success: function (d) {
        console.log(JSON.parse(d.message))
    },
});

For the data shown in the question `d.message` is a text and not JSON, why should the OP try to parse that? If the retruned data is correctly recognized as JSON then `d` would alread hold the parsed object. — t.niese, Aug 15 '17 at 05:05

score -1 · Answer 4 · edited Aug 15 '17 at 09:56

-1

echo json_encode($response, true);

edited Aug 15 '17 at 09:56

Carl Binalla

5,153
5
25
44

answered Aug 15 '17 at 09:33

syntaxe

112
4

ajax can not receive JSON from php

4 Answers4