262 add wails shutdown method (#264)

* feat: support close in bridge mode

* feat: WailsShutdown callback

Now handles proper shutdown through:
  * runtime.Window.Close()
  * Killing the main window
  * Ctrl-C

lib/binding/manager.go

@@ -16,6 +16,7 @@ type Manager struct {
 	functions        map[string]*boundFunction
 	internalMethods  *internalMethods
 	initMethods      []*boundMethod
+	shutdownMethods  []*boundMethod
 	log              *logger.CustomLogger
 	renderer         interfaces.Renderer
 	runtime          interfaces.Runtime // The runtime object to pass to bound structs
@@ -127,6 +128,9 @@ func (b *Manager) bindMethod(object interface{}) error {
 		if newMethod.isWailsInit {
 			b.log.Debugf("Detected WailsInit function: %s", fullMethodName)
 			b.initMethods = append(b.initMethods, newMethod)
+		} else if newMethod.isWailsShutdown {
+			b.log.Debugf("Detected WailsShutdown function: %s", fullMethodName)
+			b.shutdownMethods = append(b.shutdownMethods, newMethod)
 		} else {
 			// Save boundMethod
 			b.log.Infof("Bound Method: %s()", fullMethodName)
@@ -292,3 +296,13 @@ func (b *Manager) callWailsInitMethods() error {
 	}
 	return nil
 }
+
+// Shutdown the binding manager
+func (b *Manager) Shutdown() {
+	b.log.Debug("Shutdown called")
+	for _, method := range b.shutdownMethods {
+		b.log.Debugf("Calling Shutdown for method: %s", method.fullName)
+		method.call("[]")
+	}
+	b.log.Debug("Shutdown complete")
+}

lib/binding/method.go

@@ -18,6 +18,7 @@ type boundMethod struct {
 	log                *logger.CustomLogger
 	hasErrorReturnType bool // Indicates if there is an error return type
 	isWailsInit        bool
+	isWailsShutdown    bool
 }
 
 // Creates a new bound method based on the given method + type
@@ -39,6 +40,11 @@ func newBoundMethod(name string, fullName string, method reflect.Value, objectTy
 		err = result.processWailsInit()
 	}
 
+	// Are we a WailsShutdown method?
+	if result.Name == "WailsShutdown" {
+		err = result.processWailsShutdown()
+	}
+
 	return result, err
 }
 
@@ -211,3 +217,20 @@ func (b *boundMethod) processWailsInit() error {
 
 	return nil
 }
+
+func (b *boundMethod) processWailsShutdown() error {
+	// We must have only 1 input, it must be *wails.Runtime
+	if len(b.inputs) != 0 {
+		return fmt.Errorf("Invalid WailsShutdown() definition. Expected 0 inputs, but got %d", len(b.inputs))
+	}
+
+	// We must have only 1 output, it must be error
+	if len(b.returnTypes) != 0 {
+		return fmt.Errorf("Invalid WailsShutdown() definition. Expected 0 return types, but got %d", len(b.returnTypes))
+	}
+
+	// We are indeed a wails Shutdown method
+	b.isWailsShutdown = true
+
+	return nil
+}

lib/event/manager.go

@@ -3,18 +3,21 @@ package event
 import (
 	"fmt"
 	"sync"
+	"time"
+
+	"github.com/wailsapp/wails/lib/interfaces"
 	"github.com/wailsapp/wails/lib/logger"
 	"github.com/wailsapp/wails/lib/messages"
-	"github.com/wailsapp/wails/lib/interfaces"
 )
 
 // Manager handles and processes events
 type Manager struct {
 	incomingEvents chan *messages.EventData
 	listeners      map[string][]*eventListener
-	exit           bool
+	running        bool
 	log            *logger.CustomLogger
 	renderer       interfaces.Renderer // Messages will be dispatched to the frontend
+	wg             sync.WaitGroup
 }
 
 // NewManager creates a new event manager with a 100 event buffer
@@ -22,7 +25,7 @@ func NewManager() interfaces.EventManager {
 	return &Manager{
 		incomingEvents: make(chan *messages.EventData, 100),
 		listeners:      make(map[string][]*eventListener),
-		exit:           false,
+		running:        false,
 		log:            logger.NewCustomLogger("Events"),
 	}
 }
@@ -87,15 +90,14 @@ func (e *Manager) Start(renderer interfaces.Renderer) {
 	// Store renderer
 	e.renderer = renderer
 
-	// Set up waitgroup so we can wait for goroutine to start
-	var wg sync.WaitGroup
-	wg.Add(1)
+	// Set up waitgroup so we can wait for goroutine to quit
+	e.running = true
+	e.wg.Add(1)
 
 	// Run main loop in separate goroutine
 	go func() {
-		wg.Done()
 		e.log.Info("Listening")
-		for e.exit == false {
+		for e.running {
 			// TODO: Listen for application exit
 			select {
 			case event := <-e.incomingEvents:
@@ -139,14 +141,18 @@ func (e *Manager) Start(renderer interfaces.Renderer) {
 						}
 					}
 				}
+			default:
+				time.Sleep(1 * time.Millisecond)
 			}
 		}
+		e.wg.Done()
 	}()
-
-	// Wait for goroutine to start
-	wg.Wait()
 }
 
-func (e *Manager) stop() {
-	e.exit = true
+// Shutdown is called when exiting the Application
+func (e *Manager) Shutdown() {
+	e.log.Debug("Shutting Down")
+	e.running = false
+	e.log.Debug("Waiting for main loop to exit")
+	e.wg.Wait()
 }

lib/interfaces/bindingmanager.go

@@ -7,4 +7,5 @@ type BindingManager interface {
 	Bind(object interface{})
 	Start(renderer Renderer, runtime Runtime) error
 	ProcessCall(callData *messages.CallData) (result interface{}, err error)
+	Shutdown()
 }

lib/interfaces/eventmanager.go

@@ -8,4 +8,5 @@ type EventManager interface {
 	Emit(eventName string, optionalData ...interface{})
 	On(eventName string, callback func(...interface{}))
 	Start(Renderer)
+	Shutdown()
 }

lib/interfaces/ipcmanager.go

@@ -5,4 +5,5 @@ type IPCManager interface {
 	BindRenderer(Renderer)
 	Dispatch(message string)
 	Start(eventManager EventManager, bindingManager BindingManager)
+	Shutdown()
 }

lib/ipc/manager.go

@@ -2,6 +2,8 @@ package ipc
 
 import (
 	"fmt"
+	"sync"
+	"time"
 
 	"github.com/wailsapp/wails/lib/interfaces"
 	"github.com/wailsapp/wails/lib/logger"
@@ -12,18 +14,20 @@ import (
 type Manager struct {
 	renderer     interfaces.Renderer // The renderer
 	messageQueue chan *ipcMessage
-	// quitChannel  chan struct{}
+	quitChannel  chan struct{}
 	// signals      chan os.Signal
 	log            *logger.CustomLogger
 	eventManager   interfaces.EventManager
 	bindingManager interfaces.BindingManager
+	running        bool
+	wg             sync.WaitGroup
 }
 
 // NewManager creates a new IPC Manager
 func NewManager() interfaces.IPCManager {
 	result := &Manager{
 		messageQueue: make(chan *ipcMessage, 100),
-		// 		quitChannel:  make(chan struct{}),
+		quitChannel:  make(chan struct{}),
 		// 		signals:      make(chan os.Signal, 1),
 		log: logger.NewCustomLogger("IPC"),
 	}
@@ -44,9 +48,12 @@ func (i *Manager) Start(eventManager interfaces.EventManager, bindingManager int
 
 	i.log.Info("Starting")
 	// signal.Notify(manager.signals, os.Interrupt)
+	i.running = true
+
+	// Keep track of this goroutine
+	i.wg.Add(1)
 	go func() {
-		running := true
-		for running {
+		for i.running {
 			select {
 			case incomingMessage := <-i.messageQueue:
 				i.log.DebugFields("Processing message", logger.Fields{
@@ -117,15 +124,12 @@ func (i *Manager) Start(eventManager interfaces.EventManager, bindingManager int
 				i.log.DebugFields("Finished processing message", logger.Fields{
 					"1D": &incomingMessage,
 				})
-				// 			case <-manager.quitChannel:
-				// 				Debug("[MessageQueue] Quit caught")
-				// 				running = false
-				// 			case <-manager.signals:
-				// 				Debug("[MessageQueue] Signal caught")
-				// 				running = false
+			default:
+				time.Sleep(1 * time.Millisecond)
 			}
 		}
 		i.log.Debug("Stopping")
+		i.wg.Done()
 	}()
 }
 
@@ -167,3 +171,11 @@ func (i *Manager) SendResponse(response *ipcResponse) error {
 	// Call back to the front end
 	return i.renderer.Callback(data)
 }
+
+// Shutdown is called when exiting the Application
+func (i *Manager) Shutdown() {
+	i.log.Debug("Shutdown called")
+	i.running = false
+	i.log.Debug("Waiting of main loop shutdown")
+	i.wg.Wait()
+}

lib/renderer/bridge.go

@@ -156,7 +156,7 @@ func (h *Bridge) Run() error {
 	h.log.Info("The frontend will connect automatically.")
 
 	err := h.server.ListenAndServe()
-	if err != nil {
+	if err != nil && err != http.ErrServerClosed {
 		h.log.Fatal(err.Error())
 	}
 	return err
@@ -250,5 +250,9 @@ func (h *Bridge) SetTitle(title string) {
 // Close is unsupported for Bridge but required
 // for the Renderer interface
 func (h *Bridge) Close() {
-	h.log.Warn("Close() unsupported in bridge mode")
+	h.log.Debug("Shutting down")
+	err := h.server.Close()
+	if err != nil {
+		h.log.Errorf(err.Error())
+	}
 }