Support auto reconnection

A new option `--auto-reconnect` which takes seconds to reconnect is
added.

README.md

@@ -56,7 +56,7 @@ By default, gotty starts a web server at port 8080. Open the URL on your web bro
 --random-url, -r                                             Add a random string to the URL [$GOTTY_RANDOM_URL]
 --profile-file, -f "~/.gotty"                                Path to profile file [$GOTTY_PROFILE_FILE]
 --title-format "GoTTY - {{ .Command }} ({{ .Hostname }})"    Title format of browser window [$GOTTY_TITLE_FORMAT]
---version, -v                                                print the version
+--auto-reconnect "-1"                                        Seconds to automatically reconnect to the server when the connection is closed (default: disabled) [$GOTTY_AUTO_RECONNECT]
 ```
 
 By default, gotty doesn't allow clients to send any keystrokes or commands except terminal window resizing. When you want to permit clients to write input to the PTY, add the `-w` option. However, accepting input from remote clients is dangerous for most commands. Make sure that only trusted clients can connect to your gotty server when you activate this option. If you need interaction with the PTY, consider starting gotty with tmux or GNU Screen and run your main command on it.

app/app.go

@@ -32,14 +32,15 @@ type App struct {
 }
 
 type Options struct {
-	Address     string
-	Port        string
-	PermitWrite bool
-	Credential  string
-	RandomUrl   bool
-	ProfileFile string
-	TitleFormat string
-	Command     []string
+	Address       string
+	Port          string
+	PermitWrite   bool
+	Credential    string
+	RandomUrl     bool
+	ProfileFile   string
+	TitleFormat   string
+	AutoReconnect int
+	Command       []string
 }
 
 const DefaultProfileFilePath = "~/.gotty"

app/client_context.go

@@ -28,9 +28,10 @@ const (
 )
 
 const (
-	Output         = '0'
-	SetWindowTitle = '1'
-	SetPreferences = '2'
+	Output           = '0'
+	SetWindowTitle   = '1'
+	SetPreferences   = '2'
+	SetAutoReconnect = '3'
 )
 
 type argResizeTerminal struct {
@@ -124,6 +125,17 @@ func (context *clientContext) sendInitialize() error {
 	writer.Write(prefs)
 	writer.Close()
 
+	if context.app.options.AutoReconnect >= 0 {
+		autoReconnect, _ := json.Marshal(context.app.options.AutoReconnect)
+		writer, err = context.connection.NextWriter(websocket.TextMessage)
+		if err != nil {
+			return err
+		}
+		writer.Write([]byte{SetAutoReconnect})
+		writer.Write(autoReconnect)
+		writer.Close()
+	}
+
 	return nil
 }
 

main.go

@@ -55,6 +55,12 @@ func main() {
 			Usage:  "Title format of browser window",
 			EnvVar: "GOTTY_TITLE_FORMAT",
 		},
+		cli.IntFlag{
+			Name:   "auto-reconnect",
+			Value:  -1,
+			Usage:  "Seconds to automatically reconnect to the server when the connection is closed (default: disabled)",
+			EnvVar: "GOTTY_AUTO_RECONNECT",
+		},
 	}
 	cmd.Action = func(c *cli.Context) {
 		if len(c.Args()) == 0 {
@@ -72,6 +78,7 @@ func main() {
 				c.Bool("random-url"),
 				c.String("profile-file"),
 				c.String("title-format"),
+				c.Int("auto-reconnect"),
 				c.Args(),
 			},
 		)

resources/gotty.js

@@ -2,62 +2,84 @@
     var httpsEnabled = window.location.protocol == "https:";
     var url = (httpsEnabled ? 'wss://' : 'ws://') + window.location.host + window.location.pathname + 'ws';
     var protocols = ["gotty"];
-    var ws = new WebSocket(url, protocols);
+    var autoReconnect = -1;
 
-    var term;
+    var openWs = function() {
+        var ws = new WebSocket(url, protocols);
 
-    ws.onopen = function(event) {
-        hterm.defaultStorage = new lib.Storage.Local();
-        hterm.defaultStorage.clear();
+        var term;
 
-        term = new hterm.Terminal();
+        ws.onopen = function(event) {
+            hterm.defaultStorage = new lib.Storage.Local();
+            hterm.defaultStorage.clear();
 
-        term.onTerminalReady = function() {
-            var io = term.io.push();
+            term = new hterm.Terminal();
 
-            io.onVTKeystroke = function(str) {
-                ws.send("0" + str);
-            };
+            term.onTerminalReady = function() {
+                var io = term.io.push();
+
+                io.onVTKeystroke = function(str) {
+                    ws.send("0" + str);
+                };
 
-            io.sendString = io.onVTKeystroke;
+                io.sendString = io.onVTKeystroke;
 
-            io.onTerminalResize = function(columns, rows) {
-                ws.send(
-                    "1" + JSON.stringify(
-                        {
-                            columns: columns,
-                            rows: rows,
-                        }
+                io.onTerminalResize = function(columns, rows) {
+                    ws.send(
+                        "1" + JSON.stringify(
+                            {
+                                columns: columns,
+                                rows: rows,
+                            }
+                        )
                     )
-                )
+                };
+
+                term.installKeyboard();
             };
 
-            term.installKeyboard();
+            term.decorate(document.body);
         };
 
-        term.decorate(document.body);
-    };
-
-    ws.onmessage = function(event) {
-        data = event.data.slice(1);
-        switch(event.data[0]) {
-        case '0':
-            term.io.writeUTF16(data);
-            break;
-        case '1':
-            term.setWindowTitle(data);
-            break;
-        case '2':
-            preferences = JSON.parse(data);
-            Object.keys(preferences).forEach(function(key) {
-                term.getPrefs().set(key, preferences[key]);
-            });
-            break;
+        ws.onmessage = function(event) {
+            data = event.data.slice(1);
+            switch(event.data[0]) {
+            case '0':
+                term.io.writeUTF16(data);
+                break;
+            case '1':
+                term.setWindowTitle(data);
+                break;
+            case '2':
+                preferences = JSON.parse(data);
+                Object.keys(preferences).forEach(function(key) {
+                    term.getPrefs().set(key, preferences[key]);
+                });
+                break;
+            case '3':
+                autoReconnect = JSON.parse(data);
+                break;
+            }
+        }
+
+        ws.onclose = function(event) {
+            if (term) {
+                term.uninstallKeyboard();
+                term.io.showOverlay("Connection Closed", null);
+            }
+            tryReconnect();
+        }
+
+        ws.onerror = function(error) {
+            tryReconnect();
         }
     }
 
-    ws.onclose = function(event) {
-        term.io.showOverlay("Connection Closed", null);
-        term.uninstallKeyboard();
+    openWs();
+
+    var tryReconnect = function() {
+        if (autoReconnect >= 0) {
+            setTimeout(openWs, autoReconnect * 1000);
+        }
     }
 })()