Error retrieving the current token in a Blazor application after successful authentication in Azure B2C with Msal

[vsfeedback]

This issue has been moved from a ticket on Developer Community.

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I have created a Blazor application and I use Msal to do authentication following the examples from Azure B2C.
With my B2C configuration in the server, I can successfully login, I get the User, the claims and I can call the api.
I would need to have access to the token during development to be able to use that token to call my api services directly using swagger. So during Debugging I wanted to print the token on screen to copy and paste.

However, when I try to get the token in the Client after successful login, I get an Exception:
An exception occurred executing JS interop: The JSON value could not be converted to System.DateTimeOffset. Path: $.token.expires

This is a very confusing exception and doesn't seem to explain the type of error that is occurring. It seems that is not doing any validation during the parsing or pre-parsing. So not sure why this is happening.

More details:

I initialise with this:

builder. Services.AddMsalAuthentication(options =>
            {
                builder. Configuration.Bind("AzureAdB2C", options. ProviderOptions.Authentication);

//options. ProviderOptions.DefaultAccessTokenScopes.Add("02200220-20202-2020-2020-202020200202002"); // I tried to put the application Id a per documentation and it doesn't work

options. ProviderOptions.DefaultAccessTokenScopes.Add("openid");
                options. ProviderOptions.DefaultAccessTokenScopes.Add("offline_access");

// request scope to access the API
                options. ProviderOptions.AdditionalScopesToConsent.Add("https://myb2c.onmicrosoft.com/whateverApp/MyAPI");

options. ProviderOptions.LoginMode = "redirect";
            });

I also use a custom AuthorizationMessageHandler to be able to call the api, which works well.

However, when in my code I call the code to retrieve the Token, I get the exception + one unhandled exception:

[Inject]
public IAccessTokenProvider TokenProvider { get; set; }
...
var accessTokenResult = await TokenProvider.RequestAccessToken(); // <-- This throws exception

And additionally there is an unhandled exception:

Unhandled Exception:
System.Text.Json.JsonException: Invalid JSON
   at Microsoft.JSInterop.Infrastructure.DotNetDispatcher.EndInvokeJS(JSRuntime jsRuntime, String arguments)
   at Microsoft.AspNetCore.Components.WebAssembly.Services.DefaultWebAssemblyJSRuntime.<>c.<EndInvokeJS> b__7_0(String argsJson)
   at Microsoft.AspNetCore.Components.WebAssembly.Hosting.WebAssemblyCallQueue.Schedule[String](String state, Action`1 callback)
   at Microsoft.AspNetCore.Components.WebAssembly.Services.DefaultWebAssemblyJSRuntime.EndInvokeJS(String argsJson)
Uncaught Error: System.Text.Json.JsonException: Invalid JSONThe thread 0x1b444 has exited with code 0 (0x0).

I have tried in B2C to set the configuration, and I'm able to run the SignIn flow redirecting to jwt.ms passing the token and decoding it.

And I get the token decoded when redirecting directly to jwt.ms:

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Original Comments

Feedback Bot on 11/12/2021, 00:15 AM:

We have directed your feedback to the appropriate engineering team for further evaluation. The team will review the feedback and notify you about the next steps.

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Original Solutions

(no solutions)

[mkArtakMSFT]

Thanks for contacting us. This is already fixed as part of #38962 / #39060.

[TanayParikh]

Please note, the fix for this issue should be available in the 6.0.2 patch release.

[rmencia-isv]

Any estimates on this?
I've got this installed 6.0.200-preview.21617.4 and still not working

[TanayParikh]

The fix for the underlying System.Text.Json.JsonException: Invalid JSON exception was backported through #39075.

@rmencia-isv could you please try this out using the latest installer available at https://github.com/dotnet/installer. Please let us know if you're still having the issue with that, and please provide the exact version of the dotnet sdk being used, along side the exact exception message you're getting.

[rmencia-isv]

I have installed the latest versionfrom the url you provided (dotnet-sdk-6.0.200-preview.22068.4-win-x64.exe) and I still get the same error in Blazor wasm client app.

Checking the list I have this one installed (6.0.200-preview.22068.4)
However, by looking at the call stack I see references to Microsoft.AspNetCore.Components.WebAssembly.Authentication, Version=6.0.1.0*

The error Message:
An exception occurred executing JS interop: The JSON value could not be converted to System.DateTimeOffset. Path: $.token.expires | LineNumber: 0 | BytePositionInLine: 73.. See InnerException for more details.

InnerException:
at System.Text.Json.ThrowHelper.ReThrowWithPath(ReadStack& state, Utf8JsonReader& reader, Exception ex)
at System.Text.Json.Serialization.JsonConverter1[[Microsoft.AspNetCore.Components.WebAssembly.Authentication.InternalAccessTokenResult, Microsoft.AspNetCore.Components.WebAssembly.Authentication, Version=6.0.1.0, Culture=neutral, PublicKeyToken=adb9793829ddae60]].ReadCore(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state) at System.Text.Json.Serialization.JsonConverter1[[Microsoft.AspNetCore.Components.WebAssembly.Authentication.InternalAccessTokenResult, Microsoft.AspNetCore.Components.WebAssembly.Authentication, Version=6.0.1.0, Culture=neutral, PublicKeyToken=adb9793829ddae60]].ReadCoreAsObject(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
at System.Text.Json.JsonSerializer.ReadCore[Object](JsonConverter jsonConverter, Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
at System.Text.Json.JsonSerializer.Read[Object](Utf8JsonReader& reader, JsonTypeInfo jsonTypeInfo)
at System.Text.Json.JsonSerializer.Deserialize(Utf8JsonReader& reader, Type returnType, JsonSerializerOptions options)
at Microsoft.JSInterop.JSRuntime.EndInvokeJS(Int64 taskId, Boolean succeeded, Utf8JsonReader& jsonReader)'

[TanayParikh]

by looking at the call stack I see references to Microsoft.AspNetCore.Components.WebAssembly.Authentication, Version=6.0.1.0*

Ah that's definitely a bit strange. Could you please double check your csproj files to ensure you don't have any hardcoded versions which may be causing this issue? Also, if you could try adding the following to your nuget config:

<add key="dotnet6" value="https://dnceng.pkgs.visualstudio.com/public/_packaging/dotnet6/nuget/v3/index.json" />

Further details here.

[rmencia-isv]

This is what I have in the project file.
I also added the nuget in VS to get the packages from that place and no new updates available, even pre-release for any of those packages.

[TanayParikh]

Hey @rmencia-isv, I took a look at the feeds and you're right the 6.0.2 (prerelease) packages aren't up yet. You can either try waiting for the official 6.0.2 release (mid February), or try the 7.0 alpha packages (not sure if they'll be updated yet though).

[rmencia-isv]

Thanks Tanay for getting back to me. It's unfortunate that the packages are not uploaded yet, as I've seen a number of issues fixed.
I'll probably wait for the release next month, if the pre release packages are not updated.