tokenAuth.php

<?php
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//  Name: Threadz
//  Author: Matt Lewis
//  Organization: Eastern Washington University - Instructional Technology
//  Copyright: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License
//  Version: 1.0
//  Page Description: This page sets the access token from the LTI for the user. If LTI validates, this page then collects data from LMS then redirects to display page threadz.
//  Called From: The LTI connection from LMS.
//  Uses: function.php, blti.php, lms/canvas-data.php (lms data collection page)
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
session_start();
//Redirect retuns the state and code variables.
$state_test = isset($_REQUEST['state']) ? $_REQUEST['state'] : '';
$code = isset($_REQUEST['code']) ? $_REQUEST['code'] : '';
$error = isset($_REQUEST['error']) ? $_REQUEST['error'] : '';

if($error){
    echo "Access Denied <br>";
    echo "Canvas Error: " . $error;
    exit();
}

//include the functions that connect to the API data
include("functionsLMS.php");

//Check to make sure the state passed into the auth request is the same one returned.
if($_SESSION['token_state_id'] == $state_test){
    //Post request with client_id, client_secret, and code (returned from above redirect) to /login/oauth2/token to obtain access token.
    $token_url = $_SESSION['domainLMS'].'/login/oauth2/token';
    $token_data = array('client_id' => $_SESSION['client_id'], 'redirect_uri' => $_SESSION['domainThreadz'] . "/tokenAuth.php", 'client_secret' => $_SESSION['client_secret'], 'code' => $code);    

    //http://stackoverflow.com/questions/5647461/how-do-i-send-a-post-request-with-php
    $token_options = array(
        // use key 'http' even if you send the request to https://...
        'http' => array(
            'header'  => "Content-type: application/x-www-form-urlencoded\r\n",
            //'header'  => "Content-type: application/x-www-form-urlencoded\r\nUser-Agent:MyAgent/1.0\r\n",
            'method'  => 'POST',
            'content' => http_build_query($token_data),
            'proxy' => $_SESSION['proxy'],
        ),
    );
    
    $context  = stream_context_create($token_options);
    if($lms == 'canvas' & $_SESSION['proxy'] != NULL){
        //For those running off a proxy server and using Canvas
        $result = connectCanvasAPI($token_url,$token_data,'Post',$_SESSION['proxy']);
    }else{
        $result = file_get_contents($token_url, false, $context);
    }
    //Error Checking
    if($result == false){
        echo "ERROR: no data was returned from the access request<br>";
        print_r($token_options);
        exit();
    }

    // save token into variable
    $jsonToken = json_decode($result, true);
    if($jsonToken['access_token'] == ""){
        echo "Was not able to authenticate into Canvas, no access token was generated: see tokenAuth.php";
        exit();
    }else{
        $current_token = $jsonToken['access_token'];
        $refresh_token = $jsonToken['refresh_token'];
        //Collect the data from the lms page
        include("lms/". $_SESSION['dataPage']);
        
////////////////////////////////////////////////////////        
//testing the data saved into SESSION
    //foreach($_SESSION as $key => $val){
    //    echo $key ." = " . $val . "<br>";
    //}
    //exit();
////////////////////////////////////////////////////////   
    
        //redirect to display page
        header('Location: '.$_SESSION['domainThreadz'].'/threadz.php');
        exit();
    }
}else{
    echo "Altered States.";
    exit();
}




?>