Formstack OAuth2 Flow

oauth2test.php

<?php
define('CLIENT_ID', 'YOUR_CLIENT_ID');
define('CLIENT_SECRET', 'YOUR_CLIENT_SECRET');
define('REDIRECT_URL', 'YOUR_REDIRECT_URL'); // for testing, use the URL to this PHP file.

define('AUTHORIZE_URL', 'https://www.formstack.com/api/v2/oauth2/authorize');
define('TOKEN_URL', 'https://www.formstack.com/api/v2/oauth2/token');

if (!empty($_GET['code'])) {
    
    /** 
     * We have an authorization code. We now exchange it for an access token.
     */
    $ch = curl_init(TOKEN_URL);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
    curl_setopt($ch, CURLOPT_POST, 1); 
    curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query(array(
        'grant_type' => 'authorization_code',
        'client_id' => CLIENT_ID,
        'redirect_uri' => REDIRECT_URL,
        'client_secret' => CLIENT_SECRET,
        'code' => $_GET['code']
    )));
    
    // oauth2 contains the the access_token.
    $oauth2 = json_decode(curl_exec($ch));
    

    /** 
     * Make an API call.
     */
    $ch = curl_init('https://www.formstack.com/api/v2/form');
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
    curl_setopt($ch, CURLOPT_HTTPHEADER, array(
        'Authorization: Bearer ' . $oauth2->access_token
    )); 
    $forms = json_decode(curl_exec($ch));

    print '<pre>';
    print_r($forms);
    print '</pre>';

} else {
    
    /** 
     *  Send the user to the authorization page.
     */
    $auth_url = AUTHORIZE_URL . '?' . http_build_query(array(
        'client_id' => CLIENT_ID,
        'redirect_uri' => REDIRECT_URL,
        'response_type' => 'code'
    )); 
    
    header('Location:' . $auth_url);
    exit;
}