Using JSON in PHP

JSON is a great option for transferring data between servers and to the client because it’s the standardised way of doing it.

This is what JSON looks like:

{
  "key": "value",
  "number": 12
}

So in PHP you could receive JSON as a string and use in-built functions to convert it to an array or an object – json_decode.

Or, you could take an existing array or object in PHP and convert it to JSON to send on somewhere else – json_encode.

Encoding into JSON

We can encode an array or an object into JSON using the json_encode in-built PHP function.

It takes the following parameters:

1. A value – anything that isn’t a resource and usually an array or object.
2. A flag – an optional parameter which sets some options for the JSON that is output like pretty print (enter a 0 to skip this if you need the third parameter).
3. Depth – a number greater than zero describing how far down an array or object the functin should go from the top (i.e., 2 = two levels).

Here’s some sample code:

<?php

$anArray = array('dan' => 1, 'ben' => 2, 'tom' => 3);
echo json_encode($arr);

// Output: {"dan":1,"ben":2,"tom":3}

?>

Decoding from JSON

And here’s an example going the other way around.

<?php

$json = '{"dan":1,"ben":2,"tom":3}';

var_dump(json_decode($json));
/*

Output:

object(stdClass)#1 (3) {
    ["dan"] => int(1)
    ["ben"] => int(2)
    ["tom"] => int(3)
}

*/

var_dump(json_decode($json, true));
/*

Output:

array(3) {
    ["dan"] => int(1)
    ["ben"] => int(2)
    ["tom"] => int(3)
}

*/

?>

And that’s how you work with JSON in PHP.