Attempt to re-authenticate when access token expires

src/API/Kitsu.php

@@ -26,6 +26,8 @@ class Kitsu {
 	const AUTH_URL = 'https://kitsu.io/api/oauth/token';
 	const AUTH_USER_ID_KEY = 'kitsu-auth-userid';
 	const AUTH_TOKEN_CACHE_KEY = 'kitsu-auth-token';
+	const AUTH_TOKEN_EXP_CACHE_KEY = 'kitsu-auth-token-expires';
+	const AUTH_TOKEN_REFRESH_CACHE_KEY = 'kitsu-auth-token-refresh';
 
 	/**
 	 * Determine whether an anime is airing, finished airing, or has not yet aired

src/API/Kitsu/Auth.php

@@ -90,13 +90,74 @@ class Auth {
 			$cacheItem->set($auth['access_token']);
 			$cacheItem->save();
 
+			// Set the token expiration in the cache
+			$expire_time = $auth['created_at'] + $auth['expires_in'];
+			$cacheItem = $this->cache->getItem(K::AUTH_TOKEN_EXP_CACHE_KEY);
+			$cacheItem->set($expire_time);
+			$cacheItem->save();
+
+			// Set the refresh token in the cache
+			$cacheItem = $this->cache->getItem(K::AUTH_TOKEN_REFRESH_CACHE_KEY);
+			$cacheItem->set($auth['refresh_token']);
+			$cacheItem->save();
+
+			// Set the session values
 			$this->segment->set('auth_token', $auth['access_token']);
+			$this->segment->set('auth_token_expires', $expire_time);
+			$this->segment->set('refresh_token', $auth['refresh_token']);
 			return TRUE;
 		}
 
 		return FALSE;
 	}
 
+
+	/**
+	 * Make the call to re-authenticate with the existing refresh token
+	 *
+	 * @param string $token
+	 * @return boolean
+	 */
+	public function reAuthenticate(string $token)
+	{
+		try
+		{
+			$auth = $this->model->reAuthenticate($token);
+		}
+		catch (Exception $e)
+		{
+			return FALSE;
+		}
+
+		if (FALSE !== $auth)
+		{
+			// Set the token in the cache for command line operations
+			$cacheItem = $this->cache->getItem(K::AUTH_TOKEN_CACHE_KEY);
+			$cacheItem->set($auth['access_token']);
+			$cacheItem->save();
+
+			// Set the token expiration in the cache
+			$expire_time = $auth['created_at'] + $auth['expires_in'];
+			$cacheItem = $this->cache->getItem(K::AUTH_TOKEN_EXP_CACHE_KEY);
+			$cacheItem->set($expire_time);
+			$cacheItem->save();
+
+			// Set the refresh token in the cache
+			$cacheItem = $this->cache->getItem(K::AUTH_TOKEN_REFRESH_CACHE_KEY);
+			$cacheItem->set($auth['refresh_token']);
+			$cacheItem->save();
+
+			// Set the session values
+			$this->segment->set('auth_token', $auth['access_token']);
+			$this->segment->set('auth_token_expires', $expire_time);
+			$this->segment->set('refresh_token', $auth['refresh_token']);
+			return TRUE;
+		}
+
+		return FALSE;
+	}
+
+
 	/**
 	 * Check whether the current user is authenticated
 	 *
@@ -124,7 +185,18 @@ class Auth {
 	 */
 	public function get_auth_token()
 	{
+		$token = $this->segment->get('auth_token', FALSE);
+		$refresh_token = $this->segment->get('refresh_token', FALSE);
+		$isExpired = time() > $this->segment->get('auth_token_expires', 0);
+
+		// Attempt to re-authenticate with refresh token
+		if ($isExpired && $refresh_token)
+		{
+			$reauthenticated = $this->reAuthenticate($refresh_token);
 			return $this->segment->get('auth_token', FALSE);
 		}
+
+		return $token;
+	}
 }
 // End of KitsuAuth.php

src/API/Kitsu/Model.php

@@ -97,7 +97,7 @@ class Model {
 	 *
 	 * @param string $username
 	 * @param string $password
-	 * @return bool|string
+	 * @return bool|array
 	 */
 	public function authenticate(string $username, string $password)
 	{
@@ -120,6 +120,32 @@ class Model {
 		return FALSE;
 	}
 
+	/**
+	 * Extend the current session with a refresh token
+	 *
+	 * @param string $token
+	 * @return bool|array
+	 */
+	public function reAuthenticate(string $token)
+	{
+		$response = $this->getResponse('POST', K::AUTH_URL, [
+			'headers' => [],
+			'form_params' => [
+				'grant_type' => 'refresh_token',
+				'refresh_token' => $token
+			]
+		]);
+
+		$data = Json::decode((string)$response->getBody());
+
+		if (array_key_exists('access_token', $data))
+		{
+			return $data;
+		}
+
+		return FALSE;
+	}
+
 	/**
 	 * Get the userid for a username from Kitsu
 	 *