[Blazor] localStorage.getItem errors with complex objects

[JonathanShrek]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I created a fairly complex object that I want to store in local storage. The object gets set in local storage, but when I go to get the item from local storage I get a pretty generic error and the server hangs and dies.

"Error: Connection disconnected with error 'Error: Server returned an error on close: Connection closed with an error.'."

Expected Behavior

To be able hold more complex objects in local storage and retrieve them without an error.

Steps To Reproduce

https://github.com/kobrien603/BlazoredLocalStorageErrorExample

Exceptions (if any)

No response

.NET Version

6.0.101

Anything else?

No response

[mkArtakMSFT]

Thanks for contacting us. Maybe you're exceeding the SignalR message size limit? Here is a relevant issue with a proposed solution: Blazored/SessionStorage#51

Hi @JonathanShrek. We have added the "Needs: Author Feedback" label to this issue, which indicates that we have an open question for you before we can take further action. This issue will be closed automatically in 7 days if we do not hear back from you by then - please feel free to re-open it if you come back to this issue after that time.

[JonathanShrek]

Thanks for the quick response! The proposed solution actually resolved my issue. Is there Microsoft documentation anywhere that talks about adjusting the SignalR message size limit? I feel like I have looked high and low trying to fix this issue and didn't see this as a source of my problem.

[guardrex]

The Blazor docs cross-link to the SignalR docs for MaximumReceiveMessageSize ...

https://docs.microsoft.com/aspnet/core/signalr/configuration#configure-server-options

[TanayParikh]

Thanks @guardrex for providing the link.

@JonathanShrek please note, for security reasons, it's recommended to keep the max message size small.

@guardrex @BrennanConroy should we add some documentation in https://docs.microsoft.com/aspnet/core/signalr/configuration#configure-server-options / https://docs.microsoft.com/aspnet/core/signalr/security?view=aspnetcore-6.0 about avoiding large MaximumReceiveMessageSizes?

[guardrex]

Blazor docs only cross-link to SignalR docs for it, merely showing it in a code example. I can't speak to the SignalR side; but if some Blazor coverage is best for this, I can add something like the following. It turns out that Steve's Blazor threat mitigation guidance already lists the setting in its DOS section, so I can cross-link that, too.

> [!WARNING]
> We recommend setting <xref:Microsoft.AspNetCore.SignalR.HubOptions.MaximumReceiveMessageSize> to a small value in order to limit the risk of [Denial of service (DoS) attacks](xref:blazor/security/server/threat-mitigation#denial-of-service-dos-attacks). The default value is 32 KB (32,768 bytes).

... under the example code at the end of the section ...

https://docs.microsoft.com/en-us/aspnet/core/blazor/fundamentals/signalr?view=aspnetcore-6.0#circuit-handler-options-for-blazor-server-apps

UPDATE: I put that WARNING up on the docs PR dotnet/AspNetCore.Docs#27014. You can let me know here if you agree with the update 👂. Alternatives are ...

• Use an INCLUDE and place this in both docs (or place it in both without an INCLUDE).
• Only place it in the SignalR doc because the Blazor doc already links there for this type of information.