Fixed redirects for downloading artifacts

By keeping track of the last request, we know if it is being
redirected. The following request will overwrite the last stored
state.

To be able to keep track of redirects, we need to be after the
RedirectPlugin.

Author: Wouter0100

lib/Gitlab/Client.php

@@ -82,11 +82,11 @@ public function __construct(Builder $httpClientBuilder = null)
 
         $this->httpClientBuilder->addPlugin(new GitlabExceptionThrower());
         $this->httpClientBuilder->addPlugin(new HistoryPlugin($this->responseHistory));
-        $this->httpClientBuilder->addPlugin(new ApiVersion());
         $this->httpClientBuilder->addPlugin(new HeaderDefaultsPlugin([
             'User-Agent' => 'php-gitlab-api (http://github.com/m4tthumphrey/php-gitlab-api)',
         ]));
         $this->httpClientBuilder->addPlugin(new RedirectPlugin());
+        $this->httpClientBuilder->addPlugin(new ApiVersion());
 
         $this->setUrl('https://gitlab.com');
     }

lib/Gitlab/HttpClient/Plugin/ApiVersion.php

@@ -5,6 +5,7 @@
 
 use Http\Client\Common\Plugin;
 use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
 
 /**
  * Prefix requests path with /api/v4/ if required.
@@ -13,17 +14,23 @@
  */
 class ApiVersion implements Plugin
 {
+    private $redirected = false;
+
     /**
      * {@inheritdoc}
      */
     public function handleRequest(RequestInterface $request, callable $next, callable $first)
     {
         $uri = $request->getUri();
 
-        if (substr($uri->getPath(), 0, 8) !== '/api/v4/') {
+        if (substr($uri->getPath(), 0, 8) !== '/api/v4/' && !$this->redirected) {
             $request = $request->withUri($uri->withPath('/api/v4/'.$uri->getPath()));
         }
 
-        return $next($request);
+        return $next($request)->then(function (ResponseInterface $response) {
+            $this->redirected = $response->getStatusCode() === 302;
+
+            return $response;
+        });
     }
 }