Merge pull request #1 from viviedu/vivi-5527-parse-service-data

VIVI-5527 parse service data

README.md

@@ -1,3 +1,9 @@
+# VIVI SPECIFIC NOTES
+
+This repository contains a modified version of `noble-winrt` which allows for better BLE scanning. Hopefully this is made redundant by the web bluetooth API, which is partially supported by Chrome. For now, we need this library to retrieve the advertisement data broadcast by all boxes in the vicinity.
+
+The unmodified version of `noble-winrt` does not even attempt to retrieve any service data. This version of `noble-winrt` retrieves service data associated with 16 bit UUIDs from the raw AD structures that comprise the advertisement payload. The prebuilt `BLEServer.exe` comes from the `web-bluetooth-polyfill` repository that vivi also has a copy of. That version of `web-bluetooth-polyfill` has been modified to serialise the raw AD structure data so it can be serialised here.
+
 # Noble (Node.js Bluetooth LE) Bindings for Windows
 
 `noble-winrt` is a small UWP-to-noble bridge based on the [web-bluetooth-polyfill](https://github.com/urish/web-bluetooth-polyfill) project. It supports BLE connectivity on Windows without the need for a dongle and complicated driver set-up. It is similar to [noble-uwp](https://github.com/jasongin/noble-uwp) but may work better for some build processes. 

bindings.js

@@ -18,6 +18,8 @@ function fromWindowsUuid(uuid) {
     return uuid.replace(/\{|\}/g, '');
 }
 
+const adTypeServiceData16BitUUID = 0x16;
+
 class WinrtBindings extends events.EventEmitter {
     init() {
         this._deviceMap = {};
@@ -152,7 +154,7 @@ class WinrtBindings extends events.EventEmitter {
                     txPowerLevel: 0,
                     manufacturerData: null,
                     serviceUuids: message.serviceUuids.map(fromWindowsUuid),
-                    serviceData: [],
+                    serviceData: this._retrieveServiceData(message.adStructures),
                 };
                 this.emit(
                     'discover',
@@ -190,6 +192,17 @@ class WinrtBindings extends events.EventEmitter {
         }
     }
 
+    // This will only retrieve service data with 16 bit UUIDs. If you need
+    // anything else, parse the relevant adStructures
+    _retrieveServiceData(adStructures) {
+        return adStructures
+            .filter((adStructure) => adStructure.type === adTypeServiceData16BitUUID)
+            .map((adStructure) => ({
+                uuid: this._toHex(adStructure.data[1]) + this._toHex(adStructure.data[0]),
+                data: Buffer.from(adStructure.data.slice(2))
+            }));
+    }
+
     _sendMessage(message) {
         debug('out:', message);
         const dataBuf = Buffer.from(JSON.stringify(message), 'utf-8');
@@ -206,6 +219,11 @@ class WinrtBindings extends events.EventEmitter {
             this._sendMessage(Object.assign({}, message, { _id: requestId }));
         });
     }
+
+    // converts a number in range 0-255 to a two byte hex code like "C4"
+    _toHex(number) {
+        return number.toString(16).padStart(2, '0').toUpperCase();
+    }
 }
 
 exports.WinrtBindings = WinrtBindings;

index.js

@@ -6,12 +6,12 @@ if (os.platform() === 'win32') {
     if (!(ver[0] > 10 ||
         (ver[0] === 10 && ver[1] > 0) ||
         (ver[0] === 10 && ver[1] === 0 && ver[2] >= 15014))) {
-        throw new Error('Noble WinRT bindings require Windows >= 10.0.15014.');
+        module.exports = require('@abandonware/noble');
     }
 
-    const Noble = require('noble/lib/noble');
+    const Noble = require('@abandonware/noble/lib/noble');
     const { WinrtBindings } = require('./bindings.js');
     module.exports = new Noble(new WinrtBindings());
 } else {
-    module.exports = require('noble');;
+    module.exports = require('@abandonware/noble');
 }

package.json

@@ -7,9 +7,9 @@
   "author": "Uri Shaked",
   "license": "MIT",
   "dependencies": {
+    "@abandonware/noble": "^1.9.2-11",
     "chrome-native-messaging": "^0.2.0",
-    "debug": "^2.6.8",
-    "noble": "^1.7.0"
+    "debug": "^2.6.8"
   },
   "engines": {
     "node": ">=6.4.0"