fix: proxy web device resources transparently

internal/webdevice/service.go

@@ -61,6 +61,7 @@ type Service struct {
 	mu              sync.RWMutex
 	allowed         map[string]time.Time
 	forwarders      map[string]*webDeviceForwarder
+	proxyLimiters   map[string]chan struct{}
 	interfaceGetter InterfaceGetter
 	hostLANGetter   InterfaceGetter
 	tcpScanner      TCPScanner
@@ -73,6 +74,7 @@ func NewService() *Service {
 	return &Service{
 		allowed:         make(map[string]time.Time),
 		forwarders:      make(map[string]*webDeviceForwarder),
+		proxyLimiters:   make(map[string]chan struct{}),
 		interfaceGetter: defaultInterfaceGetter,
 		hostLANGetter:   defaultHostLANInterfaceGetter,
 		tcpScanner:      scanTCP,
@@ -256,6 +258,20 @@ func (s *Service) ProxyTargetURL(ip string) string {
 	return s.proxyTarget(ip)
 }
 
+func (s *Service) proxyLimiter(ip string) chan struct{} {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.proxyLimiters == nil {
+		s.proxyLimiters = make(map[string]chan struct{})
+	}
+	limiter := s.proxyLimiters[ip]
+	if limiter == nil {
+		limiter = make(chan struct{}, webDeviceProxyConcurrency)
+		s.proxyLimiters[ip] = limiter
+	}
+	return limiter
+}
+
 func IsPrivateIPv4Literal(value string) bool {
 	ip := net.ParseIP(value)
 	if ip == nil {