feat: add supervisor prototype with embedded frontend

internal/static/serve.go

@@ -0,0 +1,52 @@
+package static
+
+import (
+	"io/fs"
+	"net/http"
+	"path"
+)
+
+type SPAHandler struct {
+	assets fs.FS
+	files  http.Handler
+}
+
+func NewSPAHandler() (http.Handler, error) {
+	sub, err := fs.Sub(DistFS, "dist")
+	if err != nil {
+		return nil, err
+	}
+	return &SPAHandler{
+		assets: sub,
+		files:  http.FileServer(http.FS(sub)),
+	}, nil
+}
+
+func (h *SPAHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	requested := path.Clean(r.URL.Path)
+	if requested == "." || requested == "/" {
+		h.serveIndex(w, r)
+		return
+	}
+	candidate := requested[1:]
+	if candidate == "" {
+		h.serveIndex(w, r)
+		return
+	}
+	if file, err := h.assets.Open(candidate); err == nil {
+		_ = file.Close()
+		h.files.ServeHTTP(w, r)
+		return
+	}
+	h.serveIndex(w, r)
+}
+
+func (h *SPAHandler) serveIndex(w http.ResponseWriter, r *http.Request) {
+	index, err := fs.ReadFile(h.assets, "index.html")
+	if err != nil {
+		http.Error(w, "index.html not found", http.StatusNotFound)
+		return
+	}
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	_, _ = w.Write(index)
+}