.Net System.IO.Stream异步/非阻塞

Question

I'm wanting to wrap an external resource and convert it into a stream in my application (to be then consumed by PushStreamContent in a webapi controller).

The documentation for Streams in C# doesn't really infer how I can create one that uses the async methodology.

Eg trying to inherit from System.IO.Stream gives a very syncrhonous looking "Read" method. Ideally I would want my read to be a task that is "awaitable". Even the readAsync methods look like they expect read to be synchronous, they just get to choose the chunks.

I very want something like select in C, where I can set IO to be ready to read and then the readAsync stuff would continue reading. There may be points where there is data pending externally, so I would like the read call to defer to other tasks and continue reading when it is ready.

public override int Read(byte[] buffer, int offset, int count)
{
    throw new NotImplementedException();
}

Should I be explicitly overriding ReadAsync to accomplish this?. Is there any documentation around on how to implement your own streams in .NET

Answer 1

The basis of a readable Stream is the synchronous Read operation. The Stream class implements ReadAsync around the synchronous Read so you don't need to rewrite ReadAsync .

If the default implementation is not sufficient (such as, there are some smarts you want to inject into the asynchronous code or some performance improvements based on the internal implementation of the resource you are streaming) then you can override the BeginRead and EndRead methods.