System.Text.Encodings.Web nuget package required on server project.

[rob-github]

I had to add System.Text.Encodings.Web nuget package to server project to get this to work.
You might mention that in the tutorial.
Thanks for providing it anyway :)

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Document Details

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• ID: 08de9daf-79aa-ee76-431e-f2432f8d691e
• Version Independent ID: 1a1ee728-1741-c82a-75e1-06159709935b
• Content: Use ASP.NET Core SignalR with a hosted Blazor WebAssembly app
• Content Source: aspnetcore/tutorials/signalr-blazor-webassembly.md
• Product: aspnet-core
• Technology: aspnetcore-tutorials
• GitHub Login: @guardrex
• Microsoft Alias: riande

[guardrex]

Hello @rob-github ... I've seen this come up a few times, but I can't repro it, and the posters never say exactly what bit of API in the app is requiring it ...

• Additional Blazor SignalR tutorial updates for 5.0 #20752 (comment)
• Missing instruction to add namespace #20645

Can you say what API is requiring it in the app? ... perhaps paste in the method to clarify it so that I can try and repro this again.

[guardrex]

Also, please specify more environment details: Framework version? SDK version? Platform (OS)?

... and which set of specific IDE instructions did you follow ... VS, VS4Mac, VSCode, or CLI?

[BrennanConroy]

This is a bug when users use System.Text.Json 5.0 in a netcoreapp3.1 project.
Issue: dotnet/runtime#45560

[guardrex]

Thx @BrennanConroy ... Although Eric gave it a 5.0.x milestone, it's easy for me to surface this to readers in a NOTE [UPDATE] section (use of a section will compose better than a NOTE) and open a follow-up issue cross-linked to the engineering issue to revert the NOTE section later. It's probably the best course of action given that @rob-github is the third reader to open a docs issue on it.

[rosdi]

I just had the same problem. I just updated my dependencies and suddenly the system won't run on the server anymore with this error (it runs fine in Visual Studio).

Adding System.Text.Encodings.Web 5.0.1 explicitly into my ASP.NET Core 5.0 project makes the error goes away.