Allow createUserCallable to return user entity too

README.md

@@ -63,7 +63,13 @@ return [
             $userProvider = new \Hrevert\OauthClient\Entity\UserProvider();
             $userProvider->setUser($user);
 
-            return $userProvider;
+            return $userProvider; 
+
+            // or just
+
+            $user = ......;
+
+            return $user;
         }
     ]
 ];

src/Grant/Oauth2Client.php

@@ -18,6 +18,8 @@
 use League\OAuth2\Client\Exception\IDPException;
 use ZfrOAuth2\Server\Grant\AuthorizationServerAwareInterface;
 use ZfrOAuth2\Server\Grant\AuthorizationServerAwareTrait;
+use Hrevert\OauthClient\Entity\UserProvider;
+use Hrevert\OauthClient\Model\UserInterface;
 
 class Oauth2Client extends AbstractGrant implements AuthorizationServerAwareInterface
 {    
@@ -124,8 +126,16 @@ public function createTokenResponse(HttpRequest $request, Client $client = null,
             // access token is valid but the user does not exists
             $createUserCallable = $this->options->getCreateUserCallable();
 
-            /** @var \Hrevert\OauthClient\Model\UserProviderInterface */
+            // by default, we expect the callable to return instance of "Hrevert\OauthClient\Model\UserProviderInterface"
+            // because the developer may have extended the default implementation
+            // Alternatively the callable may return user entity directly
             $userProvider = $createUserCallable($userDetails);
+            if ($userProvider instanceof UserInterface) {
+                $user = $userProvider;
+                $userProvider = new UserProvider;
+                $userProvider->setUser($user);
+            }
+
             $userProvider->setProviderUid($userDetails->uid);
             $userProvider->setProvider($provider);
         }