Hi @ye4241,

The sample you have provided is in general against the philosophy that this library has adopted and use case it aims to satisfy (that is closer to supporting Server-Sent Event broadcasting at scale, or in HTMX scenarios).

It looks rather like attempting to reuse one of its primitives to achieve completely different behaviour (handling Server-Sent Events requests one-by-one in controllers).

In the past I would be quite eager to consider this direction, but currently ASP.NET Core itself is handling that particular usecase very nicely with Minimal APIs. Below articles can be a good starting point for difference between the two:

• https://www.jetbrains.com/guide/dotnet/tutorials/htmx-aspnetcore/server-sent-events/
• https://khalidabuhakmeh.com/server-sent-events-in-aspnet-core-and-dotnet-10

@tpeczek

The main reason I want to implement this is to create logic on an endpoint that dynamically evaluates the Accept header, similar to OpenAI's approach.

If the Accept header is set to text/event-stream, the endpoint should return results using Server-Sent Events (SSE).
On the other hand, if the header is set to application/json, it should directly return a JSON response.

@ye4241

Content negotiation is generally available with this library (for use cases that it supports) as the ServerSentEventsService middleware is not a terminal one for exactly that purpose.

You can register the middleware for a specific path (typically with UseWhen) - it will grab the requests with text/event-stream but different media types (like aplication/json) will be passed through and can be handled by a controller action on the same path.

For use cases that are better handled by the new ASP.NET Core 10 capabilities you can achieve similar there by checking the Accept header and returning different result types.

@tpeczek Alright, if the constructor isn't made accessible, perhaps the only options are the two approaches mentioned above. Alternatively, using a using statement followed by construction might also be a good way to ensure automatic disposal.

@ye4241 It is also possible that the .NET 10 has added the exact primitive you are looking for: https://devblogs.microsoft.com/dotnet/dotnet-10-networking-improvements/#server-sent-events-formatter

In general, I'm going to close this pull request as it pushes the library in unintended direction.

Okay, I will try SSE with .NET 10.0.