v0.2.0 (#50)

Co-authored-by: Tasnim Kabir Sadik <tksadik@omukk.dev>

Reviewed-on: wrenn/wrenn#50

internal/api/handlers_sse.go

@@ -0,0 +1,79 @@
+package api
+
+import (
+	"fmt"
+	"net/http"
+	"time"
+
+	"git.omukk.dev/wrenn/wrenn/pkg/auth"
+	"git.omukk.dev/wrenn/wrenn/pkg/id"
+)
+
+const sseKeepaliveInterval = 30 * time.Second
+
+type sseHandler struct {
+	broker *SSEBroker
+}
+
+func newSSEHandler(broker *SSEBroker) *sseHandler {
+	return &sseHandler{broker: broker}
+}
+
+// Stream handles GET /v1/events/stream. Authentication is performed by
+// upstream middleware: browser clients use the wrenn_sid cookie (which the
+// EventSource API forwards automatically); SDK clients use X-API-Key.
+func (h *sseHandler) Stream(w http.ResponseWriter, r *http.Request) {
+	ac, ok := auth.FromContext(r.Context())
+	if !ok {
+		writeError(w, http.StatusUnauthorized, "unauthorized", "session cookie or X-API-Key required")
+		return
+	}
+	h.serveSSE(w, r, id.FormatTeamID(ac.TeamID), false)
+}
+
+// AdminStream handles GET /v1/admin/events/stream. Upstream middleware
+// must enforce session auth + requireAdmin before reaching this handler.
+func (h *sseHandler) AdminStream(w http.ResponseWriter, r *http.Request) {
+	ac, ok := auth.FromContext(r.Context())
+	if !ok {
+		writeError(w, http.StatusUnauthorized, "unauthorized", "admin session required")
+		return
+	}
+	h.serveSSE(w, r, id.FormatTeamID(ac.TeamID), true)
+}
+
+func (h *sseHandler) serveSSE(w http.ResponseWriter, r *http.Request, teamID string, isAdmin bool) {
+	flusher, ok := w.(http.Flusher)
+	if !ok {
+		http.Error(w, "streaming not supported", http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "text/event-stream")
+	w.Header().Set("Cache-Control", "no-cache")
+	w.Header().Set("Connection", "keep-alive")
+	w.Header().Set("X-Accel-Buffering", "no")
+
+	subID, ch := h.broker.Subscribe(teamID, isAdmin)
+	defer h.broker.Unsubscribe(subID)
+
+	fmt.Fprintf(w, "event: connected\ndata: {\"message\":\"connected\"}\n\n")
+	flusher.Flush()
+
+	keepalive := time.NewTicker(sseKeepaliveInterval)
+	defer keepalive.Stop()
+
+	ctx := r.Context()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case msg := <-ch:
+			fmt.Fprintf(w, "event: %s\ndata: %s\n\n", msg.EventType, msg.Data)
+			flusher.Flush()
+		case <-keepalive.C:
+			fmt.Fprintf(w, ": keepalive\n\n")
+			flusher.Flush()
+		}
+	}
+}