FIX ME [This is not working]

ionic-hw-transport-ble

Ionic 4 @ledgerhq/hw-transport with ionic native bluetoothLE

Intro

Hi, thank you for your interest. I'm trying to make a bluetooth transport for stellar ledger to communicate with my Ledger Nano X using bluetooth to sign transaction and programmatically view my assets using ionic 4

Tried

Clone this repo and run $ npm install Assuming you have your platform setup for developing ionic applications with cordova run

$ ionic cordova platform add android This will setup your application for building to android

In your file system's project folder, navigate to the file node_modules/@ledgerhq/hw-transport-web-ble/lib-es/TransportWebBLE.js I know, you should never do this, just for testing

Change

const requiresBluetooth = () => {
  // $FlowFixMe
  const {
    bluetooth
  } = navigator;

  if (typeof bluetooth === "undefined") {
    throw new Error("web bluetooth not supported");
  }

  return bluetooth;
};

To

const requiresBluetooth = () => {
  // $FlowFixMe
  const { ionic_ble } = navigator;

  if (typeof ionic_ble === "undefined") {
    throw new Error("web bluetooth not supported");
  }

  return ionic_ble;
};

to match src/app/app.component.ts

Run $ ionic cordova build android --device -l This will run application in your device, Note Make sure it's connected with a data cable and debug mode is enabled

Plan

Since the library @ledgerhq/hw-transport-web-ble uses navigator.bluetooth and node-web-bluetooth provides the same APIs, I thought I could build the same

So I wrote the same implementation checkout src/app/ble

Problem

In the file node_modules/@ledgerhq/hw-transport-web-ble/lib-es/TransportWebBLE.js

I can't figure out how this method works and what I'm missing.

  async inferMTU() {
    let mtu = 23;
    await this.exchangeAtomicImpl(async () => {
      try {
        mtu =
          (await merge(
            this.notifyObservable.pipe(
              first(buffer => buffer.readUInt8(0) === 0x08),
              map(buffer => buffer.readUInt8(5))
            ),
            defer(() => from(this.write(Buffer.from([0x08, 0, 0, 0, 0])))).pipe(
              ignoreElements()
            )
          ).toPromise()) + 3;
      } catch (e) {
        log("ble-error", "inferMTU got " + String(e));
        this.device.gatt.disconnect();
        throw e;
      }
    });

    if (mtu > 23) {
      const mtuSize = mtu - 3;
      log(
        "ble-verbose",
        `BleTransport(${String(this.id)}) mtu set to ${String(mtuSize)}`
      );
      this.mtuSize = mtuSize;
    }

    return this.mtuSize;
  }

If someone can help that would be really great for my organisation and the community

Thank you