Obsolete

Abandoned in favor of smtech/oauth2-canvaslms, which extends the PHP League's excellent OAuth2 Client., _(*1)

OAuthNegotiator

, _(*2)

I find it difficult to wrap my head around negotiating for OAuth tokens -- and I would prefer not to have to think about it. This is particularly focused on negotiating with Instructure Canvas for OAuth tokens, to be sure., _(*3)

Usage

Include in your composer.json file:, _(*4)

{
  "requires" : {
    "smtech/oauth-negotiator": "1.0"
  }
}

When you would like to acquire a token, the easiest use of this is to provide three pages (keep reading for a single page variant):, _(*5)

page1.php

<html>
  <body>
    <form action="page2.php" method="post">
      <label>Enter the URL of your canvas instance</label>
      <input type="text" name="url" placeholder="https://canvas.instructure.com" />
      <input type="submit" value="Negotiate!" />
    </form>
  </body>
</html>

page2.php

page2.php will be re-loaded several times throughout the negotiation, so it's easiest to simply isolate this part of the negotiation on its own page and redirect in and out of that page., _(*6)

<?php
  $oauth = new OAuthNegotiator(
    $_REQUEST['url'] . '/login/oauth2',
    '0000000001', // Canvas developer ID
    '6987c1e292a98deff97c97f2cbc49985', // Canvas developer key/secret (referred to both ways in their documentation)
    'page3.php', // where to go when we're done
    'OAuthNegotiator' // your purpose for this token (displayed on the user settings page in Canvas)
  );
?>

page3.php

<?php
  $oauth = new OAuthNegotiator();

  // get your token
  echo $oauth->getToken();

  // get the user information associated with that token
  print_r($oauth->getUser());
?>

Single Page Usage

/* attempt to create a simple OAuthNegotiator for the intermediate steps in the workflow */
try {
    $oauth = new OAuthNegotiator();
} catch (OAuthNegotiator_Exception $e) {}

/* otherwise, check what step in the workflow we're at */
if (isset($_REQUEST['oauth'])) {
    switch ($_REQUEST['oauth']) {
        case 'request': { // explain what's up to the user
            echo '
<html>
    <body>
        <h1>Token Request</h1>
        <p>Explain why you&rsquo;re requesting a token.</p>
        <p><a href="' . $_SERVER['PHP_SELF'] . '?oauth=process">Click to continue</a></p>
    </body>
</html>';
            exit;
        }
        case 'process': { // start the negotiation process
            $oauth = new OAuthNegotiator(
                "https://canvas.instructure.com/login/oauth2", // replace with your OAuth provider endpoint
                (string) $secrets->oauth->id,
                (string) $secrets->oauth->key,
                "{$_SERVER['PHP_SELF']}?oauth=complete",
                (string) $secrets->app->name
            );
            break;
        }
        case 'complete': { // negotiation is complete
            /* do something productive with your token */
            $_SESSION['apiToken'] = $oauth->getToken();

      /* on to the next page, token in hand! */
            header("Location: ./next.php");
            exit;
        }
    }
}

Complete documentation is in the package online., _(*7)