ethics-canvas/canvas/php/update-collaborators.php

<?php
    require_once("../../php/db_utils.php");
    
    try {
        // Connect to the database
        $database = db_connect();
        
        // Incoming data
        $canvasId = $_POST["canvas_id"];
        $username = $_POST["username"];
        
        // Update last active of the current user
        $query = 'UPDATE collaborators SET last_active = NOW() WHERE canvas_id = "' . $canvasId . '" AND collaborator = "' . $username . '";';
        
        // Run query
        db_query_no_return($database, $query);
        
        // Get collaborators
        $query = 'SELECT user.name, collaborators.collaborator, collaborators.last_active
                  FROM collaborators
                  INNER JOIN user ON collaborators.collaborator = user.username
                  WHERE canvas_id = "' . $canvasId . '"
                  ORDER BY name ASC;';
                    
        // Run query
        $recordSet = db_query_return($database, $query);
        
        // Get list of users
        $activeCollaborators = Array();
        
        // Declare index
        $index = 0;
        
        // For every collaborator
        while($record = $recordSet->fetch_assoc()) {
            // Declare the collaborator
            $activeCollaborators[$index]["name"] = $record["name"];
            $activeCollaborators[$index]["collaborator"] = $record["collaborator"];
            
            // If the user was last active within now - 7 seconds ago
            if($record["last_active"] > date("Y-m-d H:i:s", strtotime("-3607 second"))) {
                // The collaborator is active
                $activeCollaborators[$index]["active"] = 1;
            }
            else {
                // The collaborator is not active
                $activeCollaborators[$index]["active"] = 0;
            }
            
            $index++;
        }
        
        mysqli_free_result($recordSet);
        
        echo(json_encode($activeCollaborators));
        
        // Close the connection to the database
        db_close($database);
    }
    catch(Exception $e) {
        $errorMsg = $e->getMessage();
        print_r($errorMsg);
    }
?>