Add examples

examples/stream/web/main.go

@@ -0,0 +1,122 @@
+package main
+
+import (
+	"context"
+	"io"
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/gorilla/websocket"
+	proto "github.com/micro/examples/stream/server/proto"
+	"github.com/micro/go-micro/v2/client"
+	"github.com/micro/go-micro/v2/web"
+)
+
+var upgrader = websocket.Upgrader{
+	CheckOrigin: func(r *http.Request) bool { return true },
+}
+
+func Stream(cli proto.StreamerService, ws *websocket.Conn) error {
+	// Read initial request from websocket
+	var req proto.Request
+	err := ws.ReadJSON(&req)
+	if err != nil {
+		return err
+	}
+
+	// Even if we aren't expecting further requests from the websocket, we still need to read from it to ensure we
+	// get close signals
+	go func() {
+		for {
+			if _, _, err := ws.NextReader(); err != nil {
+				break
+			}
+		}
+	}()
+
+	log.Printf("Received Request: %v", req)
+
+	// Send request to stream server
+	stream, err := cli.ServerStream(context.Background(), &req)
+	if err != nil {
+		return err
+	}
+	defer stream.Close()
+
+	// Read from the stream server and pass responses on to websocket
+	for {
+		// Read from stream, end request once the stream is closed
+		rsp, err := stream.Recv()
+		if err != nil {
+			if err != io.EOF {
+				return err
+			}
+
+			break
+		}
+
+		// Write server response to the websocket
+		err = ws.WriteJSON(rsp)
+		if err != nil {
+			// End request if socket is closed
+			if isExpectedClose(err) {
+				log.Println("Expected Close on socket", err)
+				break
+			} else {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+func isExpectedClose(err error) bool {
+	if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway) {
+		log.Println("Unexpected websocket close: ", err)
+		return false
+	}
+
+	return true
+}
+
+func main() {
+	// New web service
+	service := web.NewService(
+		web.Name("go.micro.web.stream"),
+	)
+
+	if err := service.Init(); err != nil {
+		log.Fatal("Init", err)
+	}
+
+	// New RPC client
+	rpcClient := client.NewClient(client.RequestTimeout(time.Second * 120))
+	cli := proto.NewStreamerService("go.micro.srv.stream", rpcClient)
+
+	// Serve static html/js
+	service.Handle("/", http.FileServer(http.Dir("html")))
+
+	// Handle websocket connection
+	service.HandleFunc("/stream", func(w http.ResponseWriter, r *http.Request) {
+		// Upgrade request to websocket
+		conn, err := upgrader.Upgrade(w, r, nil)
+		if err != nil {
+			log.Fatal("Upgrade: ", err)
+			return
+		}
+		defer conn.Close()
+
+		// Handle websocket request
+		if err := Stream(cli, conn); err != nil {
+			log.Fatal("Echo: ", err)
+			return
+		}
+		log.Println("Stream complete")
+	})
+
+	if err := service.Run(); err != nil {
+		log.Fatal("Run: ", err)
+	}
+}