Check if user is online from another domain

[cip6791]

I would like to check if a user is logged on domain1.com and return a message on domain2. There is a lot more to the code, I only added a basic sample.

index.php on http://domain2.com

<script type="text/javascript" src="http://domain1.com/test.php?js"></script>

test.php is on http://domain1.com.

<?php
if (isset($_GET['js'])){
header("Content-type:text/javascript");
?>

function doAjax(){
$.getJSON("http://domain1.com/index.php/home/callback.php?name=name&callback=?",
function(message) {
alert("Data Saved");
});
}

document.write('<button onclick="doAjax();">Submit</button>');
<?php } ?>

<?php exit; } ?>

callback.php is on http://domain1.com. This is where I would like to check if the user is logged in or not. If the user is logged in, the file gets written, if not I want to send a message to domain2.com asking for login.

<?php
$callback = $_GET['callback'];

$name = $_GET['name'];

$myFile = "txt/tester.txt";
$fh = fopen($myFile, 'a') or die("can't open file");
fwrite($fh, $name);
fclose($fh);

header("Content-Type: application/javascript");
?>

<?php echo $callback; ?>("Message from the server");

If the below code is the message to domain2, how do I send it?

<?php echo $callback; ?>("Message from the server");

[phorce]

I'm no expert, but I think this is what you're trying to do:

- Execute a script on "domain1.com" that checks if the user is logged in
- Stores the result in JSON

- On "domain2.com" have a script that reads the JSON and then checks whether someone is signed in

Is this correct?

[cip6791]

Yeah ... but I m just not sure how to send the information.

[phorce]

Okay.. This is how I would do it..

1. Check to see if the user is online

2. Store it using JSON which would output something like this:

{"user1":"true","user2":"false"}
// user1 is signed in, user2 isn't

3. Then use something like curl to get this information
www.domain1.com/checkUser.php?key=20420420
(The key for security)

4. Decode the json and then do whatever you want on the variable.

Does this make sense, or, have I just confused you even more?

I don't see why you're storing the values in a .txt file!

[cip6791]

Yeah a bit. :) I m storing it in a txt file just for testing. It will go to a db. There's more to the code. Would it be too much to ask for you to write a small example? This is still a bit confusing, but I'll understand the code if I see it.
Thank you very much for your help.

[Stefano Mtangoo]

Use AJAX Calls from one domain to another. If they share database then just check isOnline field which you must set in that other domain!