JavaScript Object Notation (JSON) for php

Since PHP 5.2.0, the JSON extension is built-in and compiled into PHP by default.

JSON serialization interface JsonSerializable

Classes that implement JsonSerializable can customize their JSON representation when json_encode().

JsonSerializable::jsonSerialize — Specify the data that needs to be serialized into JSON

Example #1 Returns an array

<?php
    class ArrayValue implements JsonSerializable {
        public function __construct(array $array) {
            $this->array = $array;
        }
        public function jsonSerialize() {
            return $this->array;
        }
    }
    $array = [1, 2, 3];
    echo json_encode(new ArrayValue($array), JSON_PRETTY_PRINT);
?>

The above routine will output:

[
    1,
    2,
    3
]

Example #2 Returns an associative array

<?php
    class ArrayValue implements JsonSerializable {
        public function __construct(array $array) {
            $this->array = $array;
        }
        public function jsonSerialize() {
            return $this->array;
        }
    }
    $array = [&#39;foo&#39; => &#39;bar&#39;, &#39;quux&#39; => &#39;baz&#39;];
    echo json_encode(new ArrayValue($array), JSON_PRETTY_PRINT);
?>

The above routine will Output:

{
    "foo": "bar",
    "quux": "baz"
}

Example #3 Returns an integer number

<?php
    class IntegerValue implements JsonSerializable {
        public function __construct($number) {
            $this->number = (integer) $number;
        }
        public function jsonSerialize() {
            return $this->number;
        }
    }
    echo json_encode(new IntegerValue(1), JSON_PRETTY_PRINT);
?>

The above routine will output:

1

Example #4 Returns a string

<?php
    class StringValue implements JsonSerializable {
        public function __construct($string) {
            $this->string = (string) $string;
        }
        public function jsonSerialize() {
            return $this->string;
        }
    }
    echo json_encode(new StringValue(&#39;Hello!&#39;), JSON_PRETTY_PRINT);
?>

The above routine will output:

"Hello!"

JSON function

json_decode — Encodes a string in JSON format

json_encode — Encodes a variable in JSON

json_last_error_msg — Returns the error string of the last json_encode() or json_decode() call

json_last_error — Return The last error that occurred