Feature(Go): Embed and serve web UI assets

server/go/web/server.go

@@ -0,0 +1,119 @@
+package web
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/yuanyuanxiang/SimpleRemoter/server/go/logger"
+)
+
+// Server serves the web remote desktop UI: the embedded index.html, xterm.js
+// static assets, and the PWA manifest. WebSocket signaling, device list and
+// screen streaming will be wired up in later phases.
+type Server struct {
+	port int
+	log  *logger.Logger
+	srv  *http.Server
+}
+
+// New creates an HTTP server bound to the given port. port=0 disables the server.
+func New(port int, log *logger.Logger) *Server {
+	return &Server{port: port, log: log}
+}
+
+// Start launches the server in a goroutine and returns immediately.
+// If port is 0, returns nil without starting anything.
+func (s *Server) Start() error {
+	if s.port == 0 {
+		s.log.Info("HTTP server disabled (-http-port=0)")
+		return nil
+	}
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/", s.handleIndex)
+	mux.HandleFunc("/health", s.handleHealth)
+	mux.HandleFunc("/manifest.json", s.handleManifest)
+	mux.HandleFunc("/static/xterm.js", staticHandler(xtermJS, "application/javascript; charset=utf-8"))
+	mux.HandleFunc("/static/xterm.css", staticHandler(xtermCSS, "text/css; charset=utf-8"))
+	mux.HandleFunc("/static/xterm-fit.js", staticHandler(xtermFitJS, "application/javascript; charset=utf-8"))
+
+	s.srv = &http.Server{
+		Addr:              ":" + strconv.Itoa(s.port),
+		Handler:           mux,
+		ReadHeaderTimeout: 10 * time.Second,
+	}
+
+	// Bind synchronously so port-in-use / permission errors propagate to the
+	// caller instead of being lost inside the goroutine after a misleading
+	// "started" log line.
+	ln, err := net.Listen("tcp", s.srv.Addr)
+	if err != nil {
+		return fmt.Errorf("listen on :%d: %w", s.port, err)
+	}
+	s.log.Info("HTTP server started on :%d", s.port)
+	go func() {
+		if err := s.srv.Serve(ln); err != nil && !errors.Is(err, http.ErrServerClosed) {
+			s.log.Error("HTTP server stopped: %v", err)
+		}
+	}()
+	return nil
+}
+
+// Stop gracefully shuts the server down.
+func (s *Server) Stop() {
+	if s.srv == nil {
+		return
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	_ = s.srv.Shutdown(ctx)
+}
+
+func (s *Server) handleIndex(w http.ResponseWriter, r *http.Request) {
+	if r.URL.Path != "/" && r.URL.Path != "/index.html" {
+		http.NotFound(w, r)
+		return
+	}
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	w.Header().Set("Cache-Control", "no-cache")
+	_, _ = w.Write(IndexHTML)
+}
+
+func (s *Server) handleHealth(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+	_, _ = w.Write([]byte(`{"status":"ok"}`))
+}
+
+// PWA manifest. Referenced by <link rel="manifest"> in index.html.
+// Static JSON, no template needed.
+const manifestJSON = `{
+  "name": "SimpleRemoter",
+  "short_name": "Remoter",
+  "start_url": "/",
+  "display": "standalone",
+  "orientation": "any",
+  "background_color": "#1a1a2e",
+  "theme_color": "#1a1a2e"
+}`
+
+func (s *Server) handleManifest(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/manifest+json")
+	w.Header().Set("Cache-Control", "public, max-age=86400")
+	_, _ = w.Write([]byte(manifestJSON))
+}
+
+// staticHandler returns an http.HandlerFunc that serves a fixed byte slice
+// with the given content-type. Used for embedded third-party assets (xterm.js etc.)
+// that change infrequently — 1-day browser cache is fine.
+func staticHandler(body []byte, contentType string) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", contentType)
+		w.Header().Set("Cache-Control", "public, max-age=86400")
+		_, _ = w.Write(body)
+	}
+}