Added ASGI server for websocket using the sample chat application as starting point

booker/templates/booker/scanner.html

@@ -0,0 +1,47 @@
+{% extends "base.html" %}
+{% load static %}
+
+{% block title %}Scanner: {{ scanner_id }}{% endblock %}
+
+{% block content %}
+    <textarea id="chat-log" cols="100" rows="20"></textarea><br>
+    <input id="chat-message-input" type="text" size="100"><br>
+    <input id="chat-message-submit" type="button" value="Send">
+    {{ scanner_id|json_script:"room-name" }}
+    <script>
+        const roomName = JSON.parse(document.getElementById('room-name').textContent);
+
+        const chatSocket = new WebSocket(
+            'ws://'
+            + window.location.host
+            + '/ws/scannerdata/'
+            + roomName
+            + '/'
+        );
+
+        chatSocket.onmessage = function(e) {
+            const data = JSON.parse(e.data);
+            document.querySelector('#chat-log').value += (data.message + '\n');
+        };
+
+        chatSocket.onclose = function(e) {
+            console.error('Chat socket closed unexpectedly');
+        };
+
+        document.querySelector('#chat-message-input').focus();
+        document.querySelector('#chat-message-input').onkeyup = function(e) {
+            if (e.keyCode === 13) {  // enter, return
+                document.querySelector('#chat-message-submit').click();
+            }
+        };
+
+        document.querySelector('#chat-message-submit').onclick = function(e) {
+            const messageInputDom = document.querySelector('#chat-message-input');
+            const message = messageInputDom.value;
+            chatSocket.send(JSON.stringify({
+                'message': message
+            }));
+            messageInputDom.value = '';
+        };
+    </script>
+{% endblock %}