JSON with PHP

This chapter covers how to encode and decode JSON objects using PHP programming language. Let's start with preparing the environment to start our programming with PHP for JSON.

Environment

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

JSON Functions

Function	Libraries
json_encode	Returns the JSON representation of a value.
json_decode	Decodes a JSON string.
json_last_error	Returns the last error occurred.

Encoding JSON in PHP (json_encode)

PHP json_encode() function is used for encoding JSON in PHP. This function returns the JSON representation of a value on success or FALSE on failure.

Syntax

string json_encode ( $value [, $options = 0 ] )

Parameters

• value − The value being encoded. This function only works with UTF-8 encoded data.
• options − This optional value is a bitmask consisting of JSON_HEX_QUOT, JSON_HEX_TAG, JSON_HEX_AMP, JSON_HEX_APOS, JSON_NUMERIC_CHECK, JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, JSON_FORCE_OBJECT.

Example

The following example shows how to convert an array into JSON with PHP −

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

While executing, this will produce the following result −

{"a":1,"b":2,"c":3,"d":4,"e":5}

The following example shows how the PHP objects can be converted into JSON −

<?php
   class Emp {
      public $name = "";
      public $hobbies  = "";
      public $birthdate = "";
   }
 
   $e = new Emp();
   $e->name = "sachin";
   $e->hobbies  = "sports";
   $e->birthdate = date('m/d/Y h:i:s a', "8/5/1974 12:20:03 p");
   $e->birthdate = date('m/d/Y h:i:s a', strtotime("8/5/1974 12:20:03"));

   echo json_encode($e);
?>

While executing, this will produce the following result −

{"name":"sachin","hobbies":"sports","birthdate":"08\/05\/1974 12:20:03 pm"}

Decoding JSON in PHP (json_decode)

PHP json_decode() function is used for decoding JSON in PHP. This function returns the value decoded from json to appropriate PHP type.

Syntax

mixed json_decode ($json [,$assoc = false [, $depth = 512 [, $options = 0 ]]])

Paramaters

• json_string − It is an encoded string which must be UTF-8 encoded data.
• assoc − It is a boolean type parameter, when set to TRUE, returned objects will be converted into associative arrays.
• depth − It is an integer type parameter which specifies recursion depth
• options − It is an integer type bitmask of JSON decode, JSON_BIGINT_AS_STRING is supported.

Example

The following example shows how PHP can be used to decode JSON objects −

<?php
   $json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';

   var_dump(json_decode($json));
   var_dump(json_decode($json, true));
?>

While executing, it will produce the following result −

object(stdClass)#1 (5) {
   ["a"] => int(1)
   ["b"] => int(2)
   ["c"] => int(3)
   ["d"] => int(4)
   ["e"] => int(5)
}

array(5) {
   ["a"] => int(1)
   ["b"] => int(2)
   ["c"] => int(3)
   ["d"] => int(4)
   ["e"] => int(5)
}