Add Unix domain socket support for --listen

Close #4541

3 files changed, 41 insertions, 18 deletions

diff --git a/src/options.go b/src/options.go
index a0b6f514..c1f75585 100644
--- a/src/options.go
+++ b/src/options.go
@@ -206,7 +206,9 @@ Usage: fzf [options]
 
   ADVANCED
     --with-shell=STR         Shell command and flags to start child processes with
-    --listen[=[ADDR:]PORT]   Start HTTP server to receive actions (POST /)
+    --listen[=SOCKET_PATH]   Start HTTP server to receive actions via Unix domain socket
+                             (Path should end with .sock)
+    --listen[=[ADDR:]PORT]   Start HTTP server to receive actions via TCP
                              (To allow remote process execution, use --listen-unsafe)
 
   DIRECTORY TRAVERSAL        (Only used when $FZF_DEFAULT_COMMAND is not set)
diff --git a/src/server.go b/src/server.go
index 5757e160..9f1200da 100644
--- a/src/server.go
+++ b/src/server.go
@@ -46,15 +46,20 @@ type httpServer struct {
 type listenAddress struct {
 	host string
 	port int
+	sock string
 }
 
 func (addr listenAddress) IsLocal() bool {
-	return addr.host == "localhost" || addr.host == "127.0.0.1"
+	return addr.host == "localhost" || addr.host == "127.0.0.1" || len(addr.sock) > 0
 }
 
-var defaultListenAddr = listenAddress{"localhost", 0}
+var defaultListenAddr = listenAddress{"localhost", 0, ""}
 
 func parseListenAddress(address string) (listenAddress, error) {
+	if strings.HasSuffix(address, ".sock") {
+		return listenAddress{"", 0, address}, nil
+	}
+
 	parts := strings.SplitN(address, ":", 3)
 	if len(parts) == 1 {
 		parts = []string{"localhost", parts[0]}
@@ -70,7 +75,7 @@ func parseListenAddress(address string) (listenAddress, error) {
 	if len(parts[0]) == 0 {
 		parts[0] = "localhost"
 	}
-	return listenAddress{parts[0], port}, nil
+	return listenAddress{parts[0], port, ""}, nil
 }
 
 func startHttpServer(address listenAddress, actionChannel chan []*action, getHandler func(getParams) string) (net.Listener, int, error) {
@@ -80,21 +85,32 @@ func startHttpServer(address listenAddress, actionChannel chan []*action, getHan
 	if !address.IsLocal() && len(apiKey) == 0 {
 		return nil, port, errors.New("FZF_API_KEY is required to allow remote access")
 	}
-	addrStr := fmt.Sprintf("%s:%d", host, port)
-	listener, err := net.Listen("tcp", addrStr)
-	if err != nil {
-		return nil, port, fmt.Errorf("failed to listen on %s", addrStr)
-	}
-	if port == 0 {
-		addr := listener.Addr().String()
-		parts := strings.Split(addr, ":")
-		if len(parts) < 2 {
-			return nil, port, fmt.Errorf("cannot extract port: %s", addr)
+
+	var listener net.Listener
+	var err error
+	if len(address.sock) > 0 {
+		os.Remove(address.sock)
+		listener, err = net.Listen("unix", address.sock)
+		if err != nil {
+			return nil, 0, fmt.Errorf("failed to listen on %s", address.sock)
 		}
-		var err error
-		port, err = strconv.Atoi(parts[len(parts)-1])
+	} else {
+		addrStr := fmt.Sprintf("%s:%d", host, port)
+		listener, err = net.Listen("tcp", addrStr)
 		if err != nil {
-			return nil, port, err
+			return nil, port, fmt.Errorf("failed to listen on %s", addrStr)
+		}
+		if port == 0 {
+			addr := listener.Addr().String()
+			parts := strings.Split(addr, ":")
+			if len(parts) < 2 {
+				return nil, port, fmt.Errorf("cannot extract port: %s", addr)
+			}
+			var err error
+			port, err = strconv.Atoi(parts[len(parts)-1])
+			if err != nil {
+				return nil, port, err
+			}
 		}
 	}
 
diff --git a/src/terminal.go b/src/terminal.go
index 9a014d14..cf95623c 100644
--- a/src/terminal.go
+++ b/src/terminal.go
@@ -1268,7 +1268,9 @@ func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor
 			return nil, err
 		}
 		t.listener = listener
-		t.listenPort = &port
+		if port > 0 {
+			t.listenPort = &port
+		}
 	}
 
 	if t.hasStartActions {
@@ -1292,6 +1294,9 @@ func (t *Terminal) environForPreview() []string {
 
 func (t *Terminal) environImpl(forPreview bool) []string {
 	env := os.Environ()
+	if t.listenAddr != nil && len(t.listenAddr.sock) > 0 {
+		env = append(env, "FZF_SOCK="+t.listenAddr.sock)
+	}
 	if t.listenPort != nil {
 		env = append(env, fmt.Sprintf("FZF_PORT=%d", *t.listenPort))
 	}