CODEWITHSUNDEEP
phpajaxobject
frrlod
frrlod

Reputation: 6685

Passing php objects to $.post()

I would like to pass 2 php objects as data, as they are, to $.post.

        $(function() {
            $("button").click(function() {  
                $.post("fight.php",{player: "<?php $player;?>", enemy: "<?php $enemy; ?>"},function(result) {
                    $("#displayFight").html(result);
                });
            });
        });

$player, $enemy are 2 different objects with a few properties each. I would like to pass them as the whole objects they are, so that fight.php can deal with them.

I've also tried serialize, but to no avail:

{player: $("<?php $player ?>").serialize()}

How can I do this?

Note: With all the methods I've tried, I either get some 'unknown identifier' or $_POST comes out empty on the receiving page.

EDIT: the json_encode part works, but the decoding fails. On the receiving page:

$player = json_decode($_POST["player"])

fails and returns an error: json_decode() expects parameter 1 to be string, array given

Upvotes: 3

Views: 6667

Answers (4)

Richard JP Le Guen
Richard JP Le Guen

Reputation: 28753

One suggestion could be to JSON encode the PHP object using json_encode.

However, let's think about this: you have a PHP script generating output. That output - which contains this Javascript snippet and the 2 objects - is sent to the client-side (the browser) where it is executed, and it re-sends those two objects back to the server with an AJAX call.

So an alternative idea might be to simply store the objects server-side the whole time in the session and only send an identifier instead of the entire object:

<?php
    // apologies for errors - my PHP's rusty
    $_SESSION[$player->uuid()] = $player;
    $_SESSION[$enemy->uuid()] = $enemy;
?>
$.post("fight.php",{player: "<?php $player->uuid();?>", enemy: "<?php $enemy->uuid(); ?>"},function(result) {
    // ...
});

Then the fight.php script would restore then:

// is this still how PHP handles sessions?
$player = $_SESSION[$_POST['player']];
$enemy  = $_SESSION[$_POST['enemy']];

If you're using a conventional framework to build a database driven application, this works particularly well because chances are your objects are stored in a database and can be read out of the database easily - which may be a better solution than using the $_SESSION array:

// if recollection serves this is CakePHP-ish
$player = $this->Player->find($_POST['player']);
$enemy  = $this->Enemy->find($_POST['enemy']);

Upvotes: 1

GriffLab
GriffLab

Reputation: 2166

Try using json_encode http://www.php.net/manual/en/function.json-encode.php

{player: <?php json_encode($player); ?>}

Upvotes: 1

Jon
Jon

Reputation: 437444

You need to use json_encode, like this:

$.post("fight.php",{
    player: <?php echo json_encode($player);?>, 
    enemy: <?php echo json_encode($enemy);?>
}, ... );

Note that there are no quotes around the <?php ?> tags; json_encode will add them automatically if required.

Apart from that, you need to be aware of the requirements that json_encode imposes: most importantly, if your objects contain string content (either as a property or as a property of any sub-objects) then these strings must be encoded in UTF-8.

Upvotes: 3

Clarence
Clarence

Reputation: 2964

To easily communicate between PHP and Javascript you should properly serialize your objects. The easiest way is to call json_encode($player) in your PHP code. Then when you are fetching it again with PHP you need to call json_decode() on it and properly initialize the object. There's no way for PHP and Javascript to share an instance of the object. Only the serialized data.

Upvotes: 1

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