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Returning JSON from PHP to JavaScript?

Posted by: admin November 29, 2017 Leave a comment

Questions:

I have a PHP script that’s being called through jQuery AJAX. I want the PHP script to return the data in JSON format to the javascript. Here’s the pseudo code in the PHP script:

$json = "{";
foreach($result as $addr)
{
    foreach($addr as $line)
    {
        $json .= $line . "\n";
    }
    $json .= "\n\n";
}
$json .= "}";

Basically, I need the results of the two for loops to be inserted in $json.

Answers:

Php has an inbuilt JSON Serialising function.

json_encode

json_encode

Please use that if you can and don’t suffer Not Invented Here syndrome.

Questions:
Answers:

There’s a JSON section in the PHP’s documentation. You’ll need PHP 5.2.0 though.

As of PHP 5.2.0, the JSON extension is bundled and compiled into PHP by default.

If you don’t, here’s the PECL library you can install.

<?php
    $arr = array ('a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5);

    echo json_encode($arr); // {"a":1,"b":2,"c":3,"d":4,"e":5}
?>

Questions:
Answers:

Here are a couple of things missing in the previous answers:

  1. Set header in your PHP:

    header('Content-type: application/json');
    echo json_encode($array);
    
  2. json_encode() can return a JavaScript array instead of JavaScript object, see:
    Returning JSON from a PHP Script
    This could be important to know in some cases as arrays and objects are not the same.

Questions:
Answers:

Usually you would be interested in also having some structure to your data in the receiving end:

json_encode($result)

This will preserve the array keys as well.

Do remember that json_encode only works on utf8 -encoded data.

Questions:
Answers:

You can use Simple JSON for PHP. It sends the headers help you to forge the JSON.

It looks like :

<?php
// Include the json class
include('includes/json.php');

// Then create the PHP-Json Object to suits your needs

// Set a variable ; var name = {}
$Json = new json('var', 'name'); 
// Fire a callback ; callback({});
$Json = new json('callback', 'name'); 
// Just send a raw JSON ; {}
$Json = new json();

// Build data
$object = new stdClass();
$object->test = 'OK';
$arraytest = array('1','2','3');
$jsonOnly = '{"Hello" : "darling"}';

// Add some content
$Json->add('width', '565px');
$Json->add('You are logged IN');
$Json->add('An_Object', $object);
$Json->add("An_Array",$arraytest);
$Json->add("A_Json",$jsonOnly);

// Finally, send the JSON.

$Json->send();
?>