WebBluetoothCG · reillyeon · Aug 5, 2025 · Jul 30, 2025 · Aug 4, 2025
diff --git a/cancel_gatt_connect/device_code.js b/cancel_gatt_connect/device_code.js
@@ -0,0 +1,48 @@
+/**
+ *  Copyright 2025 Google LLC
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+function onInit() {
+  // Put into a known state.
+  digitalWrite(LED, 0);
+
+  NRF.setServices({
+    '0b30acec-193e-11eb-adc1-0242ac120002': {
+      '0b30afd0-193e-11eb-adc1-0242ac120002': {
+        value: [17],
+        broadcast: false,
+        readable: true,
+        writable: false,
+        notify: false,
+        description: 'Single read-only characteristic',
+      }
+    }
+  });
+
+
+  NRF.on('disconnect', (reason) => {
+    // Provide feedback that device is no longer connected.
+    digitalWrite(LED, 0);
+  });
+
+  NRF.on('connect', (addr) => {
+    // Provide feedback that device is connected.
+    // TODO: Maybe only do this for some devices when external power is
+    //       available. For example, this will turn on the backlight on the
+    //       Pixl.js screen, which might not be desirable when powered by the
+    //       CR2032 coin cell battery.
+    digitalWrite(LED, 1);
+  });
+}
diff --git a/cancel_gatt_connect/index.html b/cancel_gatt_connect/index.html
@@ -0,0 +1,91 @@
+<!DOCTYPE html>
+<!--
+ Copyright 2025 Google LLC
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+-->
+
+<html>
+
+<head>
+  <meta charset="UTF-8">
+  <title>Cancel GATT connect</title>
+  <script src="../shared/shared.js"></script>
+  <script src="web_app.js"></script>
+  <link rel="stylesheet" href="../css/main.css">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0">
+</head>
+
+<body onload="init()">
+  <h1>Cancel GATT connect</h1>
+  <p>This is a simple test to check if gatt.connect() can be cancelled by gatt.disconnect().
+  </p>
+  <div id="bluetooth_available" style="visibility: visible;">
+    <h2>Step 1</h2>
+    <div class="container">
+      <div class="flex">
+        <div class="inRow">
+          Press the button to load the code to the Espruino IDE.
+          From there, flash any Bluetooth capable Espruino device.
+          <br>
+          <br>
+          View <a href="device_code.js" title="Device source code">source</a>.
+        </div>
+        <div class="inRow">
+          <button id="btn_load_code" type="button" onclick="loadEspruinoDeviceCode()">Load Device Code</button>
+        </div>
+      </div>
+    </div>
+
+    <h2>Step 2</h2>
+    <div>
+      <div class="flex">
+        <div class="inRow">
+          Press the button to start pairing.
+        </div>
+        <div class="inRow">
+          <button id="btn_start_pairing" type="button" onclick="startPairing()">Start Pairing</button>
+        </div>
+      </div>
+    </div>
+
+    <h2>Step 3</h2>
+    <div>
+      <div class="flex">
+        <div class="inRow">
+          Unplug the Espruino Pixl.js from power source and click the button.
+        </div>
+        <div class="inRow">
+          <button id="btn_connect_then_cancel" type="button" onclick="connectThenCancel()">Start connecting then cancel</button>
+        </div>
+      </div>
+    </div>
+
+    <p>Status: <span id='test_result'></span></p>
+    <pre id='status'></pre>
+  </div>
+  <!-- Only one of the three below will be visible. -->
+  <div id="bluetooth_none" class="no-bluetooth" style="visibility: hidden;">
+    Web Bluetooth is not supported by this browser.
+  </div>
+  <div id="bluetooth_insecure" class="no-bluetooth" style="visibility: hidden;">
+    Bluetooth requires a secure context (HTTPS). For development purposes it
+    does support HTTP, but only the on the loopback adapter (i.e. "localhost").
+  </div>
+  <div id="bluetooth_unavailable" class="no-bluetooth" style="visibility: hidden;">
+    Web Bluetooth is supported by this browser but this device does not have
+    Bluetooth capabilities.
+  </div>
+</body>
+
+</html>
diff --git a/cancel_gatt_connect/web_app.js b/cancel_gatt_connect/web_app.js
@@ -0,0 +1,100 @@
+/**
+ *  Copyright 2025 Google LLC
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+// Espruino devices publish a UART service by default.
+const nordicUARTService = '6e400001-b5a3-f393-e0a9-e50e24dcca9e';
+
+let device = undefined;
+
+/**
+ * Load the device code to the Espruino IDE.
+ */
+function loadEspruinoDeviceCode() {
+  fetch('device_code.js').then(response => response.text()).then(data => {
+    let url = 'http://www.espruino.com/webide?code=' + encodeURIComponent(data);
+    window.open(url, '_window');
+  });
+}
+
+async function startPairing() {
+  clearStatus();
+  logInfo('Starting test');
+
+  $('btn_load_code').disabled = true;
+  $('btn_start_pairing').disabled = true;
+  $('btn_connect_then_cancel').disabled = true;
+
+  try {
+    const options = {
+      filters: [
+        { services: [nordicUARTService] }
+      ],
+    };
+
+    device = await navigator.bluetooth.requestDevice(options);
+    logInfo(`Paired to Bluetooh device with name: ${device.name}`);
+  } catch (error) {
+    logError(`Unexpected failure: ${error}`);
+  }
+
+  $('btn_load_code').disabled = false;
+  $('btn_start_pairing').disabled = false;
+  $('btn_connect_then_cancel').disabled = false;
+}
+
+async function connectThenCancel() {
+  $('btn_load_code').disabled = true;
+  $('btn_start_pairing').disabled = true;
+  $('btn_connect_then_cancel').disabled = true;
+
+  logInfo('Try to connect then cancel');
+  try {
+    setTimeout(() => {
+      device.gatt.disconnect();
+    }, 100);
+    await device.gatt.connect();
+    logError('connect() promise was not rejected');
+  } catch (e) {
+    if (e.name !== 'AbortError') {
+      logError(`connect() promise was rejected with unexpected error: ${e}`);
+    }
+    logInfo('connect() promise was rejected with Abort error');
+  }
+
+  $('btn_load_code').disabled = false;
+  $('btn_start_pairing').disabled = false;
+  $('btn_connect_then_cancel').disabled = false;
+  testDone();
+}
+
+async function init() {
+  if (!isBluetoothSupported()) {
+    console.log('Bluetooth not supported.');
+    $('bluetooth_available').style.display = 'none';
+    if (window.isSecureContext) {
+      $('bluetooth_none').style.visibility = 'visible';
+    } else {
+      $('bluetooth_insecure').style.visibility = 'visible';
+    }
+    return;
+  }
+
+  const available = await navigator.bluetooth.getAvailability();
+  if (!available) {
+    $('bluetooth_available').style.display = 'none';
+    $('bluetooth_unavailable').style.visibility = 'visible';
+  }
+}
diff --git a/index.html b/index.html
@@ -43,6 +43,7 @@ <h2>Tests</h2>
     <li><a href="get_devices">Test navigator.bluetooth.getDevices</a></li>
     <li><a href="watch_advertisements">Test BluetoothDevice.watchAdvertisements</a></li>
     <li><a href="forget_device">Test BluetoothDevice.forget</a></li>
+    <li><a href="cancel_gatt_connect">Test cancelling a GATT connection</a></li>
   </ol>
 </body>