First commit using websocket from example from go web page

.gitignore

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+bin

go.mod

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+module kbca/sudoku
+
+go 1.17
+
+require github.com/gorilla/websocket v1.5.0 // indirect

go.sum

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+github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWmnc=
+github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=

server.go

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+package main
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/gorilla/websocket"
+)
+
+var upgrader = websocket.Upgrader{
+	ReadBufferSize:  1024,
+	WriteBufferSize: 1024,
+}
+
+func main() {
+	http.HandleFunc("/echo", func(w http.ResponseWriter, r *http.Request) {
+		conn, _ := upgrader.Upgrade(w, r, nil) // error ignored for sake of simplicity
+
+		for {
+			// Read message from browser
+			msgType, msg, err := conn.ReadMessage()
+			if err != nil {
+				return
+			}
+
+			// Print the message to the console
+			fmt.Printf("%s sent: %s\n", conn.RemoteAddr(), string(msg))
+
+			// Write message back to browser
+			if err = conn.WriteMessage(msgType, msg); err != nil {
+				return
+			}
+		}
+	})
+
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		http.ServeFile(w, r, "websockets.html")
+	})
+
+	http.ListenAndServe(":8080", nil)
+}

websockets.html

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+<input id="input" type="text" />
+<button onclick="send()">Send</button>
+<pre id="output"></pre>
+<script>
+    var input = document.getElementById("input");
+    var output = document.getElementById("output");
+    var socket = new WebSocket("ws://localhost:8080/echo");
+
+    socket.onopen = function () {
+        output.innerHTML += "Status: Connected\n";
+    };
+
+    socket.onmessage = function (e) {
+        output.innerHTML += "Server: " + e.data + "\n";
+    };
+
+    function send() {
+        socket.send(input.value);
+        input.value = "";
+    }
+</script>