title: Google Oauth error: At least one client secrets (Installed or Web) should be set
body: <p>I'm using Google's Oauth 2.0 to upload videos to Youtube via our server.
  My client ID is a "service account". I downloaded the json key and added it to my solution.</p>
  
  <p>Here is the relevant code:</p>
  
  <pre><code> private async Task Run(string filePath)
          {
              UserCredential credential;
              var keyUrl = System.Web.HttpContext.Current.Server.MapPath("~/content/oauth_key.json");
              using (var stream = new FileStream(keyUrl, FileMode.Open, FileAccess.Read))
              {
                  credential = await GoogleWebAuthorizationBroker.AuthorizeAsync(
                      GoogleClientSecrets.Load(stream).Secrets,
                      // This OAuth 2.0 access scope allows an application to upload files to the
                      // authenticated user's YouTube channel, but doesn't allow other types of access.
                      new[] { YouTubeService.Scope.YoutubeUpload },
                      "user",
                      CancellationToken.None
                  );
              }
  
              var youtubeService = new YouTubeService(new BaseClientService.Initializer()
              {
                  HttpClientInitializer = credential,
                  ApplicationName = Assembly.GetExecutingAssembly().GetName().Name
              });
  </code></pre>
  
  <p>When I run it, I get this error: At least one client secrets (Installed or Web) should be set.</p>
  
  <p>However, in my json there is no "client secret":</p>
  
  <pre><code>{
    "private_key_id": "9d98c06b3e730070806dcf8227578efd0ba9989b",
    "private_key": "-----BEGIN PRIVATE KEY-----\nMIICdQIBADANBgkqhk etc,
    "client_email": "546239405652-8igo05a5m8cutggehk3rk3hspjfm3t04@developer.gserviceaccount.com",
    "client_id": "546239405652-8igo05a5m8cutggehk3rk3hspjfm3t04.apps.googleusercontent.com",
    "type": "service_account"
  }
  </code></pre>
  
  <p>so I assume I overlooked something.
  Maybe I can't use the "service account" ? don't know...</p>