PHP: __toString() and json_encode() not playing well together

Question

I\'ve run into an odd problem and I\'m not sure how to fix it. I have several classes that are all PHP implementations of JSON objects. Here\' an illustration of the issue

Answer 1

A late answers but might be useful for others with the same problem.

In PHP < 5.4.0 json_encode doesn't call any method from the object. That is valid for getIterator, __serialize, etc...

In PHP > v5.4.0, however, a new interface was introduced, called JsonSerializable.

It basically controls the behaviour of the object when json_encode is called on that object.

---

Example:

class A implements JsonSerializable
{
    protected $a = array();

    public function __construct()
    {
        $this->a = array( new B, new B );
    }

    public function jsonSerialize()
    {
        return $this->a;
    }
}

class B implements JsonSerializable
{
    protected $b = array( 'foo' => 'bar' );

    public function jsonSerialize()
    {
        return $this->b;
    }
}


$foo = new A();

$json = json_encode($foo);

var_dump($json);

---

Outputs:

string(29) "[{"foo":"bar"},{"foo":"bar"}]"