Start PoC work on WASM bridge for bus

Signed-off-by: Josh Kim <[email protected]>

wasm/bus_bridge.go

@@ -0,0 +1,155 @@
+//go:build js && wasm
+
+// Copyright 2021 VMware, Inc.
+// SPDX-License-Identifier: BSD-2-Clause
+
+package wasm
+
+import (
+	"syscall/js"
+
+	"github.com/google/uuid"
+	"github.com/vmware/transport-go/bus"
+	"github.com/vmware/transport-go/model"
+)
+
+type TransportWasmBridge struct {
+	busRef bus.EventBus
+}
+
+func NewTransportWasmBridge(busRef bus.EventBus) *TransportWasmBridge {
+	return &TransportWasmBridge{
+		busRef: busRef,
+	}
+}
+
+func (t *TransportWasmBridge) sendRequestMessageWrapper() js.Func {
+	return js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+		var destId *uuid.UUID
+		channel := args[0].String()
+		payload := args[1].JSValue()
+		if len(args) > 2 {
+			dId, err := uuid.Parse(args[2].String())
+			if err != nil {
+				errCtor := js.Global().Get("Error")
+				js.Global().Get("console").Call("error", errCtor.New(err.Error()))
+				return nil
+			}
+			destId = &dId
+		}
+		t.busRef.SendRequestMessage(channel, payload, destId)
+		return nil
+	})
+}
+
+func (t *TransportWasmBridge) sendResponseMessageWrapper() js.Func {
+	return js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+		var destId *uuid.UUID
+		channel := args[0].String()
+		payload := args[1].JSValue()
+		if len(args) > 2 {
+			dId, err := uuid.Parse(args[2].String())
+			if err != nil {
+				errCtor := js.Global().Get("Error")
+				js.Global().Get("console").Call("error", errCtor.New(err.Error()))
+				return nil
+			}
+			destId = &dId
+		}
+		t.busRef.SendResponseMessage(channel, payload, destId)
+		return nil
+	})
+}
+
+func (t *TransportWasmBridge) listenStreamWrapper() js.Func {
+	return js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+		handler, err := t.busRef.ListenStream(args[0].String())
+		if err != nil {
+			errCtor := js.Global().Get("Error")
+			return errCtor.New(err.Error())
+		}
+
+		return map[string]interface{}{
+			"handle": getResponseHandlerJsCallbackFunc(handler),
+			"close": js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+				handler.Close()
+				return nil
+			}),
+		}
+	})
+}
+
+func (t *TransportWasmBridge) listenStreamWithIdWrapper() js.Func {
+	return js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+		if len(args) <= 1 {
+			errCtor := js.Global().Get("Error")
+			js.Global().Get("console").Call("error", errCtor.New("cannot listen to channel. missing destination ID"))
+			return nil
+		}
+
+		destId, err := uuid.Parse(args[1].String())
+		if err != nil {
+			errCtor := js.Global().Get("Error")
+			return errCtor.New(err.Error())
+		}
+
+		handler, err := t.busRef.ListenStreamForDestination(args[0].String(), &destId)
+		if err != nil {
+			errCtor := js.Global().Get("Error")
+			return errCtor.New(err.Error())
+		}
+
+		return map[string]interface{}{
+			"handle": getResponseHandlerJsCallbackFunc(handler),
+			"close": js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+				handler.Close()
+				return nil
+			}),
+		}
+	})
+}
+
+func (t *TransportWasmBridge) browserBusWrapper() js.Func {
+	return js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+		b := js.Global().Get("AppEventBus")
+		if b.Type() == js.TypeUndefined || b.Type() == js.TypeNull {
+			errCtor := js.Global().Get("Error")
+			return errCtor.New("bus not initialized")
+		}
+		return b
+	})
+}
+
+func (t *TransportWasmBridge) SetUpTransportWasmAPI() {
+	js.Global().Set("goBusInterface", map[string]interface{}{
+		"sendRequestMessage":        t.sendRequestMessageWrapper(),
+		"sendRequestMessageWithId":  t.sendRequestMessageWrapper(),
+		"sendResponseMessage":       t.sendResponseMessageWrapper(),
+		"sendResponseMessageWithId": t.sendResponseMessageWrapper(),
+		"listenStream":              t.listenStreamWrapper(),
+		"listenStreamWithId":        t.listenStreamWithIdWrapper(),
+		"getBrowserBus":             t.browserBusWrapper(),
+	})
+
+	js.Global().Get("console").Call("log", "Transport WASM bridge set up. APIs are exposed at window.goBusInterface")
+}
+
+func getResponseHandlerJsCallbackFunc(handler bus.MessageHandler) js.Func {
+	return js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+		handler.Handle(func(m *model.Message) {
+			jsCallback := args[0]
+			if jsCallback.Type() != js.TypeFunction {
+				errCtor := js.Global().Get("Error")
+				js.Global().Get("console").Call("error", errCtor.New("invalid argument. not a function."))
+				handler.Close()
+				return
+			}
+			jsCallback.Invoke(m.Payload)
+		}, func(e error) {
+			errCtor := js.Global().Get("Error")
+			js.Global().Get("console").Call("error", errCtor.New(e.Error()))
+			handler.Close()
+		})
+		return nil
+	})
+}

wasm/example/build.go

@@ -0,0 +1,3 @@
+package example
+
+//go:generate bash -c "GOARCH=wasm; GOOS=js; go build -o ${OUT_DIR}/main.wasm main.go"

wasm/example/main.go

@@ -0,0 +1,42 @@
+//go:build js && wasm
+
+// Copyright 2021 VMware, Inc.
+// SPDX-License-Identifier: BSD-2-Clause
+
+package main
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/vmware/transport-go/bus"
+	"github.com/vmware/transport-go/wasm"
+)
+
+func init() {
+	b := bus.GetBus()
+	cm := b.GetChannelManager()
+	cm.CreateChannel("goBusChan")
+	cm.CreateChannel("broadcast")
+
+	ticker := time.NewTicker(1 * time.Second)
+	go func() {
+		for {
+			select {
+			case <-ticker.C:
+				b.SendResponseMessage("goBusChan", "sending", b.GetId())
+				b.SendResponseMessage("broadcast", "hello world", nil)
+			}
+		}
+	}()
+}
+
+func main() {
+	twa := wasm.NewTransportWasmBridge(bus.GetBus())
+	twa.SetUpTransportWasmAPI()
+
+	fmt.Println("go bus id: ", bus.GetBus().GetId())
+
+	loop := make(chan struct{})
+	<-loop
+}