.NET to JS Streaming Interop

[TanayParikh]

• Supports Blazor Server, WASM & WebView
• Blazor Server leverages SignalR Streaming capabilities
• WASM & WebView have a shared implementation in which .NET sends data chunks to JS for consumption via stream.

Usage:

  using var data = new System.IO.MemoryStream(new byte[100 * 1024]);
  using var streamRef = new DotNetStreamReference(stream: data, leaveOpen: false);
  await JS.InvokeVoidAsync("consumeStream", streamRef);

async function consumeStream(streamRef) {
    const data = await streamRef.arrayBuffer();    // ArrayBuffer
    // or
    const stream = await streamRef.stream();       // ReadableStream
}

Based on @SteveSandersonMS's proof of concept: #32848 (which also has a great writeup on how the pending stream logic works for Blazor Server).

• TODO:
  • Unit Tests
  • E2E Tests

Fixes: #30289
API Review: #35009

[javiercn]

Why do we need the concurrent dictionary here? Shouldn't this already be scoped to the circuit?

[TanayParikh]

cancellationToken.Register which is used to evict streams which aren't read from after the timeout, does not capture the Synchronization context.. Hence, without a ConcurrentDictionary we could run into potential issues when the cancellation token expires (and attempts to evict the stream) at the exact time we get a call into TryClaimPendingStreamForSending to evict the stream for consumption.

[javiercn]

Code looks good, waiting for the E2E tests

[ghost]

Thank you for your API proposal. I'm removing the api-ready-for-review label. API Proposals should be submitted for review through Issues based on this template.

[TanayParikh]

This PR should be good to go now using the IAsyncEnumerable based approach to interface with SignalR streaming.

[javiercn]

I might be missing something, but I don't see the E2E tests, can you point me to them?

[TanayParikh]

I might be missing something, but I don't see the E2E tests, can you point me to them?

Hmm, they should be there under src/Components/test:

https://github.com/dotnet/aspnetcore/pull/34817/files?file-filters%5B%5D=.cs&file-filters%5B%5D=.js&file-filters%5B%5D=.razor&file-filters%5B%5D=.ts&file-filters%5B%5D=.txt#diff-00895862dbdfb71ca46c1cfb5be169faf8ab0c5640230b887caa7423a5e85291

https://github.com/dotnet/aspnetcore/pull/34817/files?file-filters%5B%5D=.cs&file-filters%5B%5D=.js&file-filters%5B%5D=.razor&file-filters%5B%5D=.ts&file-filters%5B%5D=.txt#diff-f85b3886d1e1848f29c37c7b3fbe75eedc23dfceae77670bc68104db6877f9a4

[javiercn]

Looks great!