CODEWITHSUNDEEP
azuremicrosoft-graph-api
Adam Blankenship
Adam Blankenship

Reputation: 1

Azure Ad WebApp MSGraph Value cannot be null

I'm running into an issue with AzureAd/Graph configuration between Azure and Local. I'm using Vs2019 .Net Core 5 Identity.Web 1.23 On local both in Visual Studio and stand alone exe. I am able to connect to Graph get my roles and details when the same code is deployed to the Azure Web App I get the follow.

Code: generalException Message: An error occurred sending the request. Value cannot be null. (Parameter 'headers') at Microsoft.Identity.Web.AppServicesAuthenticationInformation.GetIdToken(IDictionary2 headers) at Microsoft.Identity.Web.AppServicesAuthenticationTokenAcquisition.GetAuthenticationResultForUserAsync(IEnumerable1 scopes, String authenticationScheme, String tenantId, String userFlow, ClaimsPrincipal user, TokenAcquisitionOptions tokenAcquisitionOptions) at Microsoft.Identity.Web.TokenAcquisitionAuthenticationProvider.AuthenticateRequestAsync(HttpRequestMessage request) at Microsoft.Graph.AuthenticationHandler.SendAsync(HttpRequestMessage httpRequestMessage, CancellationToken cancellationToken) at System.Net.Http.HttpClient.SendAsyncCore(HttpRequestMessage request, HttpCompletionOption completionOption, Boolean async, Boolean emitTelemetryStartStop, CancellationToken cancellationToken) at Microsoft.Graph.HttpProvider.SendRequestAsync(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationToken cancellationToken)<Microsoft.Identity.Web

The code in question

                var initialScopes = Configuration.GetValue<string>("DownstreamApi:Scopes")?.Split(' ');
            services.AddMicrosoftIdentityWebApiAuthentication(Configuration);

            JwtSecurityTokenHandler.DefaultMapInboundClaims = false;

            services.AddAuthentication(OpenIdConnectDefaults.AuthenticationScheme)
                .AddMicrosoftIdentityWebApp(Configuration.GetSection("AzureAd"))
                    .EnableTokenAcquisitionToCallDownstreamApi(initialScopes)
                        .AddMicrosoftGraph(Configuration.GetSection("DownstreamApi"))
                        .AddInMemoryTokenCaches();
            services.Configure<OpenIdConnectOptions>(OpenIdConnectDefaults.AuthenticationScheme, options =>
            {
                options.TokenValidationParameters.RoleClaimType = "roles";
            });
            services.AddControllersWithViews(options =>
                    {
                        var policy = new AuthorizationPolicyBuilder()
                            .RequireAuthenticatedUser()
                            .Build();
                        options.Filters.Add(new AuthorizeFilter(policy));
                    }).AddMicrosoftIdentityUI();

            services.AddRazorPages()
                  .AddMicrosoftIdentityUI();

            // Add the UI support to handle claims challenges
            services.AddServerSideBlazor()
               .AddMicrosoftIdentityConsentHandler();

app.config for reference

  "AzureAd": {
    "Instance": "https://login.microsoftonline.com/",
    "ClientCertificates": [
    ],
    "CallbackPath": "/signin-oidc",
    "SignedOutCallbackPath ": "/signout-callback-oidc"
  },
  "DownstreamApi": {
    "BaseUrl": "https://graph.microsoft.com/v1.0",
    "Scopes": "User.Read"
  },

Anything pointing me in a direction would be helpful, I have been stumped by this for a week now.

Upvotes: 0

Views: 253

Answers (1)

Adam Blankenship
Adam Blankenship

Reputation: 1

I found my issue. the azure web app was running as a managed account and because of this it could not connect to graph as the user.

Upvotes: 0

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