Implement retrieveROPCToken as proposed in #1151 (comment)

Author: mkne

src/Services/InfoProviderSystem/Providers/BuerklinProvider.php

@@ -62,52 +62,16 @@ public function __construct(
      */
     private function getToken(): string
     {
-        // Cache token to avoid hammering the auth server on every request
-        $cacheKey = 'buerklin.oauth.token';
-        $item = $this->partInfoCache->getItem($cacheKey);
-
-        if ($item->isHit()) {
-            $token = $item->get();
-            if (is_string($token) && $token !== '') {
-                return $token;
-            }
-        }
-
-        // Buerklin OAuth2 password grant (ROPC)
-        $resp = $this->client->request('POST', 'https://www.buerklin.com/authorizationserver/oauth/token/', [
-            'headers' => [
-                'Accept' => 'application/json',
-                'Content-Type' => 'application/x-www-form-urlencoded',
-            ],
-            'body' => [
-                'grant_type' => 'password',
-                'client_id' => $this->settings->clientId,
-                'client_secret' => $this->settings->secret,
-                'username' => $this->settings->username,
-                'password' => $this->settings->password,
-            ],
-        ]);
-
-        $data = $resp->toArray(false);
-
-        if (!isset($data['access_token'])) {
-            throw new \RuntimeException(
-                'Invalid token response from Buerklin: HTTP ' . $resp->getStatusCode() . ' body=' . $resp->getContent(false)
-            );
+        //Check if we already have a token saved for this app, otherwise we have to retrieve one via OAuth
+        if (!$this->authTokenManager->hasToken(self::OAUTH_APP_NAME)) {
+            $this->authTokenManager->retrieveROPCToken(self::OAUTH_APP_NAME, $this->settings->username, $this->settings->password);
         }
 
-        $token = (string) $data['access_token'];
-
-        // Cache for (expires_in - 30s) if available
-        $ttl = 300;
-        if (isset($data['expires_in']) && is_numeric($data['expires_in'])) {
-            $ttl = max(60, (int) $data['expires_in'] - 30);
+        $token = $this->authTokenManager->getAlwaysValidTokenString(self::OAUTH_APP_NAME);
+        if ($token === null) {
+            throw new \RuntimeException('Could not retrieve OAuth token for Buerklin API.');
         }
 
-        $item->set($token);
-        $item->expiresAfter($ttl);
-        $this->partInfoCache->save($item);
-
         return $token;
     }
 

src/Services/OAuth/OAuthTokenManager.php

@@ -159,4 +159,21 @@ public function retrieveClientCredentialsToken(string $app_name): OAuthToken
 
         return $this->saveToken($app_name, $access_token);
     }
+
+    /**
+     * Retrieves an access token for the given app name using the client ROPC grant (so no user flow is needed)
+     * The app_name must be registered in the knpu_oauth2_client.yaml
+     * The token is saved to the database, and afterwards can be used as usual
+     * @param  string  $app_name
+     * @return OAuthToken
+     */
+    public function retrieveROPCToken(string $app_name, string $user, string $password): OAuthToken
+    {
+        $client = $this->clientRegistry->getClient($app_name);
+        $access_token = $client->getOAuth2Provider()->getAccessToken('password', [
+            'username' => $user,
+            'password' => $password
+        ];
+        return $this->saveToken($app_name, $access_token);
+    }
 }