Starting with LTI 1.3

xcesaralejandro
Community Explorer

Hello, I am new to LTI development and I am currently trying to get my first "Hello World" on LTI 1.3, but I have encountered some difficulties.

I have integrated a test application that I found on github to make sure I understand the configuration parameters, after solving a couple of problems I have succeeded.

The problem with this application is that it does not have very clean code to be able to carry this to a framework such as laravel or similar, for which I find myself in the need to understand the integration flow in detail in order to create my own work environment.

Sample application 

The problem comes because I am not receiving the id_token after executing my query, failing that I get an "authenticity_token" next to "login_required", which I don't understand exactly what it means.

My connection code looks like this:

require_once("vendor/autoload.php");
    use GuzzleHttp\Client;

    // This constant are obtained from LMS platform.
    define('PLATFORM_ID', 'https://canvas.beta.instructure.com');
    define('CLIENT_ID', 'MY_CLIENT_ID');
    define('DEPLOYMENT_ID', 'MY_DEPLOYMENT_ID');
    define('AUTHENTICATION_URL', 'https://canvas.beta.instructure.com/api/lti/authorize_redirect');
    define('PLATFORM_JSON_WEBKEY_URL', 'https://canvas.beta.instructure.com/api/lti/security/jwks');
    
    // STEP 1
    // Receiving authentication parameters
    print_r($_REQUEST);
    // die;

    // STEP 2 
    // Creating authentication request
    if(isset($_REQUEST['iss']) && isset($_REQUEST['login_hint']) && isset($_REQUEST['lti_message_hint'])){
        $nonce = getRandomString();
        $params = array(
            'client_id' => CLIENT_ID,
            'login_hint' => $_REQUEST['login_hint'],
            'lti_message_hint' => $_REQUEST['lti_message_hint'],
            'nonce' => $nonce,
            'prompt' => 'none',
            'redirect_uri' => "http://localhost/clean_integration/connect.php",
            'response_mode' => 'form_post',
            'response_type' => 'id_token',
            'scope' => 'openid',
            'state' => $nonce
        );
        $options = [
            'form_params' => $params
        ];
        try{
            $client = new Client();
            $res = $client->request('POST', AUTHENTICATION_URL, $options);
            echo $res->getBody();
        }catch(Exception $e){
            die("Exception: {$e}");
        }
    }

    function getRandomString($length = 8){
        $chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
        $value = '';
        $charsLength = strlen($chars) - 1;
        for ($i = 1; $i <= $length; $i++) {
            $value .= $chars[rand(0, $charsLength)];
        }
        return $value;
    }

 

When my app start, 

Array
(
    [iss] => https://canvas.beta.instructure.com
    [login_hint] => HINT
    [client_id] => CLIENT_ID
    [target_link_uri] => http://localhost/clean_integration/connect.php
    [lti_message_hint] => HASH1.HASH2.HASH3
    [canvas_region] => us-east-1
)

After running my request I get the following, when actually I should get the token id (From what I understand I could be wrong at this point)

Array
(
    [utf8] => ✓
    [authenticity_token] => SOME TOKEN THAT IS NOT JWT
    [error] => login_required
    [error_description] => Must have an active user session
    [state] => 9kofXdDs
)

 

If anyone can help me with the following questions I am very grateful.

1 - What am I doing wrong so that the token id with the user and resource data does not return? Am I missing a step?
2.- How can I use the member service (LTI Adventage)

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