sse

server/sse

Import path: github.com/InsideGallery/core/server/sse

sse provides basic Server-Sent Events formatting, streaming, and per-user connection pooling for net/http handlers.

Main APIs

• Message and NewMessage(event, data...): event payload model.
• FormatMSG(event, data...): renders SSE bytes using event: and data: lines.
• Run(ch, w, r): streams messages from a channel to an http.ResponseWriter.
• Pool: tracks user ID to message channel mappings.
• NewPool(bufferSize): creates a pool; non-positive sizes use the default.
• Pool.Add, Remove, Send, SendToAll, StopAll, Connections, and GetAllConnectedUsers: connection lifecycle and delivery helpers.
• Pool.Handler: HTTP handler that reads ContextUserID from request context.

Usage

pool := sse.NewPool(100)

http.HandleFunc("/events", func(w http.ResponseWriter, r *http.Request) {
	ctx := context.WithValue(r.Context(), sse.ContextUserID, "user-1")
	pool.Handler(w, r.WithContext(ctx))
})

_ = pool.Send("user-1", sse.NewMessage("notice", "hello"))

Operational Notes

Run requires a response writer that implements http.Flusher; otherwise it returns ErrResponseWriterIsNotFlusher. It sets keep-alive, text/event-stream, and wildcard CORS headers. Pool.Handler logs and returns without a connection when ContextUserID is missing or not a string.