Pass JSON object from database to JS using $.getJSON

Question

I am trying to pass a json object that I have accessed from the database through a php file into JS using $.getJSON function. I am using the json_encode() function for this. The json object stored in the database is being retrieved. However, the array that I am obtaining in php ($arr) is not being accepted by the $.getJSON function.

Please Help. Thanks!

Sample code (php):

<?php 
    $arr = array();
    while($row = mysqli_fetch_array($result)){
        $attributes = $row['attributes'];
        array_push($arr, $attributes);
    }

    $newArray = json_encode($arr);
    echo $newArray;
?>

JS code:

var i, j;
var dataset = [];
for (i=0; i < 17; i++){
    dataset[i] = [];
    for (j=0; j < 17; j++){
        dataset[i][j] = "";
    }
}
$(document).ready(function(){

    $.getJSON('getData.php', function(data) {                        
        $.each(data, function(key, val) {
            var x = val.posX,
            y = val.posY;
        });
    });
});

The following is the output when I print $newArray.

[
    "{\"position\":\"6.5\",\"posX\":6,\"posY\":5,\"type\":\"wall\"}",
    "{\"position\":\"1.2\",\"posX\":1,\"posY\":2,\"type\":\"wall\"}",
    "{\"position\":\"3.5\",\"posX\":3,\"posY\":5,\"type\":\"bee\",\"speed\":12}",
    "{\"position\":\"7.3\",\"posX\":7,\"posY\":3,\"type\":\"bee\",\"speed\":12}",
    "{\"position\":\"0.0\",\"posX\":0,\"posY\":0,\"type\":\"butterfly\",\"speed\":12,\"minspeed\":3.5,\"maxspeed\":12,\"speed_change_rate\":-0.9}",
    "{\"position\":\"4.0\",\"posX\":4,\"posY\":0,\"type\":\"butterfly\",\"speed\":12,\"minspeed\":3.5,\"maxspeed\":12,\"speed_change_rate\":-0.9}"
]

It does contain proper JSON, it just isn't very good JSON. You have a JSON array of strings. Each string is a JSON text in its own right. — Quentin
– Quentin, Commented Jun 11, 2015 at 9:10

Quentin · Accepted Answer · 2015-06-11 09:14:14Z

2

The basic problem here is that you are storing JSON in the database instead of having a database designed to hold the data you are dealing with.

i.e. Your database table should have columns for position, posX, etc.

Consequently, when you return the data to the browser you are returning a JSON array of strings where each string is a JSON text in its own right.

To deal with that, you will have to parse each string as you loop over them.

    $.each(data, function(key, val) {
        val = JSON.parse(val);
        var x = val.posX,

A better approach would be to decode each string on the server before you return it.

The best approach would be to normalise your database so you have data you can actually query.

answered Jun 11, 2015 at 9:14

Quentin

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Comments

Gary Liu · Accepted Answer · 2015-06-11 09:07:55Z

-1

try to use echo stripslashes($newArray); after json_encode

answered Jun 11, 2015 at 9:07

Gary Liu

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