Allow accepting remote connections

Close #3498

  # FZF_API_KEY is required for a non-localhost listen address
  FZF_API_KEY=xxx fzf --listen 0.0.0.0:6266

1 files changed, 39 insertions, 16 deletions

diff --git a/src/server.go b/src/server.go
index 8fc605ac..a89c5e08 100644
--- a/src/server.go
+++ b/src/server.go
@@ -26,12 +26,13 @@ type getParams struct {
 }
 
 const (
-	crlf             = "\r\n"
-	httpOk           = "HTTP/1.1 200 OK" + crlf
-	httpBadRequest   = "HTTP/1.1 400 Bad Request" + crlf
-	httpUnauthorized = "HTTP/1.1 401 Unauthorized" + crlf
-	httpReadTimeout  = 10 * time.Second
-	maxContentLength = 1024 * 1024
+	crlf              = "\r\n"
+	httpOk            = "HTTP/1.1 200 OK" + crlf
+	httpBadRequest    = "HTTP/1.1 400 Bad Request" + crlf
+	httpUnauthorized  = "HTTP/1.1 401 Unauthorized" + crlf
+	httpReadTimeout   = 10 * time.Second
+	maxContentLength  = 1024 * 1024
+	defaultListenAddr = "localhost:0"
 )
 
 type httpServer struct {
@@ -40,30 +41,52 @@ type httpServer struct {
 	responseChannel chan string
 }
 
-func startHttpServer(port int, actionChannel chan []*action, responseChannel chan string) (error, int) {
-	if port < 0 {
-		return nil, port
+func parseListenAddress(address string) (error, string, int) {
+	parts := strings.SplitN(address, ":", 3)
+	if len(parts) == 1 {
+		parts = []string{"localhost", parts[0]}
 	}
+	if len(parts) != 2 {
+		return fmt.Errorf("invalid listen address: %s", address), "", 0
+	}
+	portStr := parts[len(parts)-1]
+	port, err := strconv.Atoi(portStr)
+	if err != nil || port < 0 || port > 65535 {
+		return fmt.Errorf("invalid listen port: %s", portStr), "", 0
+	}
+	if len(parts[0]) == 0 {
+		parts[0] = "localhost"
+	}
+	return nil, parts[0], port
+}
 
-	listener, err := net.Listen("tcp", fmt.Sprintf("localhost:%d", port))
+func startHttpServer(address string, actionChannel chan []*action, responseChannel chan string) (error, int) {
+	err, host, port := parseListenAddress(address)
+	if err != nil {
+		return err, port
+	}
+
+	apiKey := os.Getenv("FZF_API_KEY")
+	if host != "localhost" && host != "127.0.0.1" && len(apiKey) == 0 {
+		return fmt.Errorf("FZF_API_KEY is required for remote access"), port
+	}
+	listener, err := net.Listen("tcp", fmt.Sprintf("%s:%d", host, port))
 	if err != nil {
-		return fmt.Errorf("port not available: %d", port), port
+		return fmt.Errorf("failed to listen on %s", address), port
 	}
 	if port == 0 {
 		addr := listener.Addr().String()
-		parts := strings.SplitN(addr, ":", 2)
+		parts := strings.Split(addr, ":")
 		if len(parts) < 2 {
 			return fmt.Errorf("cannot extract port: %s", addr), port
 		}
-		var err error
-		port, err = strconv.Atoi(parts[1])
-		if err != nil {
+		if port, err := strconv.Atoi(parts[len(parts)-1]); err != nil {
 			return err, port
 		}
 	}
 
 	server := httpServer{
-		apiKey:          []byte(os.Getenv("FZF_API_KEY")),
+		apiKey:          []byte(apiKey),
 		actionChannel:   actionChannel,
 		responseChannel: responseChannel,
 	}