Develop (#250)

lib/renderer/webview.go

@@ -0,0 +1,357 @@
+package renderer
+
+import (
+	"encoding/json"
+	"fmt"
+	"math/rand"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/go-playground/colors"
+	"github.com/leaanthony/mewn"
+	"github.com/wailsapp/wails/lib/interfaces"
+	"github.com/wailsapp/wails/lib/logger"
+	"github.com/wailsapp/wails/lib/messages"
+	wv "github.com/wailsapp/wails/lib/renderer/webview"
+)
+
+// WebView defines the main webview application window
+// Default values in []
+type WebView struct {
+	window       wv.WebView // The webview object
+	ipc          interfaces.IPCManager
+	log          *logger.CustomLogger
+	config       interfaces.AppConfig
+	eventManager interfaces.EventManager
+	bindingCache []string
+}
+
+// NewWebView returns a new WebView struct
+func NewWebView() *WebView {
+	return &WebView{}
+}
+
+// Initialise sets up the WebView
+func (w *WebView) Initialise(config interfaces.AppConfig, ipc interfaces.IPCManager, eventManager interfaces.EventManager) error {
+
+	// Store reference to eventManager
+	w.eventManager = eventManager
+
+	// Set up logger
+	w.log = logger.NewCustomLogger("WebView")
+
+	// Set up the dispatcher function
+	w.ipc = ipc
+	ipc.BindRenderer(w)
+
+	// Save the config
+	w.config = config
+
+	// Create the WebView instance
+	w.window = wv.NewWebview(wv.Settings{
+		Width:     config.GetWidth(),
+		Height:    config.GetHeight(),
+		Title:     config.GetTitle(),
+		Resizable: config.GetResizable(),
+		URL:       config.GetDefaultHTML(),
+		Debug:     !config.GetDisableInspector(),
+		ExternalInvokeCallback: func(_ wv.WebView, message string) {
+			w.ipc.Dispatch(message)
+		},
+	})
+
+	// SignalManager.OnExit(w.Exit)
+
+	// Set colour
+	err := w.SetColour(config.GetColour())
+	if err != nil {
+		return err
+	}
+
+	w.log.Info("Initialised")
+	return nil
+}
+
+// SetColour sets the window colour
+func (w *WebView) SetColour(colour string) error {
+	color, err := colors.Parse(colour)
+	if err != nil {
+		return err
+	}
+	rgba := color.ToRGBA()
+	alpha := uint8(255 * rgba.A)
+	w.window.Dispatch(func() {
+		w.window.SetColor(rgba.R, rgba.G, rgba.B, alpha)
+	})
+
+	return nil
+}
+
+// evalJS evaluates the given js in the WebView
+// I should rename this to evilJS lol
+func (w *WebView) evalJS(js string) error {
+	outputJS := fmt.Sprintf("%.45s", js)
+	if len(js) > 45 {
+		outputJS += "..."
+	}
+	w.log.DebugFields("Eval", logger.Fields{"js": outputJS})
+	//
+	w.window.Dispatch(func() {
+		w.window.Eval(js)
+	})
+	return nil
+}
+
+// Escape the Javascripts!
+func escapeJS(js string) (string, error) {
+	result := strings.Replace(js, "\\", "\\\\", -1)
+	result = strings.Replace(result, "'", "\\'", -1)
+	result = strings.Replace(result, "\n", "\\n", -1)
+	return result, nil
+}
+
+// evalJSSync evaluates the given js in the WebView synchronously
+// Do not call this from the main thread or you'll nuke your app because
+// you won't get the callback.
+func (w *WebView) evalJSSync(js string) error {
+
+	minified, err := escapeJS(js)
+
+	if err != nil {
+		return err
+	}
+
+	outputJS := fmt.Sprintf("%.45s", js)
+	if len(js) > 45 {
+		outputJS += "..."
+	}
+	w.log.DebugFields("EvalSync", logger.Fields{"js": outputJS})
+
+	ID := fmt.Sprintf("syncjs:%d:%d", time.Now().Unix(), rand.Intn(9999))
+	var wg sync.WaitGroup
+	wg.Add(1)
+
+	go func() {
+		exit := false
+		// We are done when we receive the Callback ID
+		w.log.Debug("SyncJS: sending with ID = " + ID)
+		w.eventManager.On(ID, func(...interface{}) {
+			w.log.Debug("SyncJS: Got callback ID = " + ID)
+			wg.Done()
+			exit = true
+		})
+		command := fmt.Sprintf("wails._.AddScript('%s', '%s')", minified, ID)
+		w.window.Dispatch(func() {
+			w.window.Eval(command)
+		})
+		for exit == false {
+			time.Sleep(time.Millisecond * 1)
+		}
+	}()
+
+	wg.Wait()
+
+	return nil
+}
+
+// injectCSS adds the given CSS to the WebView
+func (w *WebView) injectCSS(css string) {
+	w.window.Dispatch(func() {
+		w.window.InjectCSS(css)
+	})
+}
+
+// Exit closes the window
+func (w *WebView) Exit() {
+	w.window.Exit()
+}
+
+// Run the window main loop
+func (w *WebView) Run() error {
+
+	w.log.Info("Running...")
+
+	// Runtime assets
+	wailsRuntime := mewn.String("../../runtime/assets/wails.js")
+	w.evalJS(wailsRuntime)
+
+	// Ping the wait channel when the wails runtime is loaded
+	w.eventManager.On("wails:loaded", func(...interface{}) {
+
+		// Run this in a different go routine to free up the main process
+		go func() {
+
+			// Inject Bindings
+			for _, binding := range w.bindingCache {
+				w.evalJSSync(binding)
+			}
+
+			// Inject user CSS
+			if w.config.GetCSS() != "" {
+				outputCSS := fmt.Sprintf("%.45s", w.config.GetCSS())
+				if len(outputCSS) > 45 {
+					outputCSS += "..."
+				}
+				w.log.DebugFields("Inject User CSS", logger.Fields{"css": outputCSS})
+				w.injectCSS(w.config.GetCSS())
+			} else {
+				// Use default wails css
+				w.log.Debug("Injecting Default Wails CSS")
+				defaultCSS := mewn.String("../../runtime/assets/wails.css")
+
+				w.injectCSS(defaultCSS)
+			}
+
+			// Inject user JS
+			if w.config.GetJS() != "" {
+				outputJS := fmt.Sprintf("%.45s", w.config.GetJS())
+				if len(outputJS) > 45 {
+					outputJS += "..."
+				}
+				w.log.DebugFields("Inject User JS", logger.Fields{"js": outputJS})
+				w.evalJSSync(w.config.GetJS())
+			}
+
+			// Emit that everything is loaded and ready
+			w.eventManager.Emit("wails:ready")
+		}()
+	})
+
+	// Kick off main window loop
+	w.window.Run()
+
+	return nil
+}
+
+// NewBinding registers a new binding with the frontend
+func (w *WebView) NewBinding(methodName string) error {
+	objectCode := fmt.Sprintf("window.wails._.NewBinding('%s');", methodName)
+	w.bindingCache = append(w.bindingCache, objectCode)
+	return nil
+}
+
+// SelectFile opens a dialog that allows the user to select a file
+func (w *WebView) SelectFile() string {
+	var result string
+
+	// We need to run this on the main thread, however Dispatch is
+	// non-blocking so we launch this in a goroutine and wait for
+	// dispatch to finish before returning the result
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		w.window.Dispatch(func() {
+			result = w.window.Dialog(wv.DialogTypeOpen, 0, "Select File", "")
+			wg.Done()
+		})
+	}()
+	wg.Wait()
+	return result
+}
+
+// SelectDirectory opens a dialog that allows the user to select a directory
+func (w *WebView) SelectDirectory() string {
+	var result string
+	// We need to run this on the main thread, however Dispatch is
+	// non-blocking so we launch this in a goroutine and wait for
+	// dispatch to finish before returning the result
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		w.window.Dispatch(func() {
+			result = w.window.Dialog(wv.DialogTypeOpen, wv.DialogFlagDirectory, "Select Directory", "")
+			wg.Done()
+		})
+	}()
+	wg.Wait()
+	return result
+}
+
+// SelectSaveFile opens a dialog that allows the user to select a file to save
+func (w *WebView) SelectSaveFile() string {
+	var result string
+	// We need to run this on the main thread, however Dispatch is
+	// non-blocking so we launch this in a goroutine and wait for
+	// dispatch to finish before returning the result
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		w.window.Dispatch(func() {
+			result = w.window.Dialog(wv.DialogTypeSave, 0, "Save file", "")
+			wg.Done()
+		})
+	}()
+	wg.Wait()
+	return result
+}
+
+// Callback sends a callback to the frontend
+func (w *WebView) Callback(data string) error {
+	callbackCMD := fmt.Sprintf("window.wails._.Callback('%s');", data)
+	return w.evalJS(callbackCMD)
+}
+
+// NotifyEvent notifies the frontend about a backend runtime event
+func (w *WebView) NotifyEvent(event *messages.EventData) error {
+
+	// Look out! Nils about!
+	var err error
+	if event == nil {
+		err = fmt.Errorf("Sent nil event to renderer.WebView")
+		w.log.Error(err.Error())
+		return err
+	}
+
+	// Default data is a blank array
+	data := []byte("[]")
+
+	// Process event data
+	if event.Data != nil {
+		// Marshall the data
+		data, err = json.Marshal(event.Data)
+		if err != nil {
+			w.log.Errorf("Cannot unmarshall JSON data in event: %s ", err.Error())
+			return err
+		}
+	}
+
+	message := fmt.Sprintf("wails._.Notify('%s','%s')", event.Name, data)
+	return w.evalJS(message)
+}
+
+// Fullscreen makes the main window go fullscreen
+func (w *WebView) Fullscreen() {
+	if w.config.GetResizable() == false {
+		w.log.Warn("Cannot call Fullscreen() - App.Resizable = false")
+		return
+	}
+	w.window.Dispatch(func() {
+		w.window.SetFullscreen(true)
+	})
+}
+
+// UnFullscreen returns the window to the position prior to a fullscreen call
+func (w *WebView) UnFullscreen() {
+	if w.config.GetResizable() == false {
+		w.log.Warn("Cannot call UnFullscreen() - App.Resizable = false")
+		return
+	}
+	w.window.Dispatch(func() {
+		w.window.SetFullscreen(false)
+	})
+}
+
+// SetTitle sets the window title
+func (w *WebView) SetTitle(title string) {
+	w.window.Dispatch(func() {
+		w.window.SetTitle(title)
+	})
+}
+
+// Close closes the window
+func (w *WebView) Close() {
+	w.window.Dispatch(func() {
+		w.window.Terminate()
+	})
+}