[GitHub](https://github.com/LedgerHQ/ledger-live/), [Ledger Devs Discord](https://developers.ledger.com/discord-pro), [Developer Portal](https://developers.ledger.com/) ## @ledgerhq/hw-transport-webhid Allows to communicate with Ledger Hardware Wallets. **\[Web]** **(WebHID)** – WebHID [check browser support](https://caniuse.com/webhid). *** ## Are you adding Ledger support to your software wallet? You may be using this package to open a USB connection between your web application and the device. For a smooth and quick integration: * See the developers’ documentation on the [Developer Portal](https://developers.ledger.com/docs/transport/overview/) and * Go on [Discord](https://developers.ledger.com/discord-pro/) to chat with developer support and the developer community. *** ### FAQ: "DOM Exception" is triggered when creating the transport The transport functions `create()` and `listen()` must be called in the context of a user interaction (like a **"click"** event), otherwise it fails with DOM Exception. This is by WebUSB design. You also must run on HTTPS. ### How to use this transport? Please check `@ledgerhq/hw-transport-webusb` documentation because it is very similar paradigm. ### Support status WebUSB is currently only supported on Google Chrome / Chromium DEV version and by explicitly enabling `chrome://flags/#enable-experimental-web-platform-features` ## API #### Table of Contents * [createHIDframing](#createhidframing) * [Parameters](#parameters) * [makeBlocks](#makeblocks) * [Parameters](#parameters-1) * [reduceResponse](#reduceresponse) * [Parameters](#parameters-2) * [getReducedResult](#getreducedresult) * [Parameters](#parameters-3) * [TransportWebHID](#transportwebhid) * [Parameters](#parameters-4) * [Examples](#examples) * [close](#close) * [exchange](#exchange) * [Parameters](#parameters-5) * [isSupported](#issupported) * [list](#list) * [listen](#listen) * [Parameters](#parameters-6) * [request](#request) * [openConnected](#openconnected) * [open](#open) * [Parameters](#parameters-7) ### createHIDframing Object to handle HID frames (encoding and decoding) #### Parameters * `channel` **[number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** * `packetSize` **[number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)** The HID protocol packet size in bytes (usually 64) ### makeBlocks Frames/encodes an APDU message into HID USB packets/frames #### Parameters * `apdu` **[Buffer](https://nodejs.org/api/buffer.html)** The APDU message to send, in a Buffer containing \[cla, ins, p1, p2, data length, data(if not empty)] Returns **[Array](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array)<[Uint8Array](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array)<[ArrayBuffer](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer)>>** an array of HID USB frames ready to be sent ### reduceResponse Reduces HID USB packets/frames to one response. #### Parameters * `acc` **ResponseAcc** The value resulting from (accumulating) the previous call of reduceResponse. On first call initialized to `initialAcc`. The accumulator enables handling multi-frames messages. * `chunk` **[Buffer](https://nodejs.org/api/buffer.html)** Current chunk to reduce into accumulator Returns **ResponseAcc** An accumulator value updated with the current chunk ### getReducedResult Returns the response message that has been reduced from the HID USB frames #### Parameters * `acc` **ResponseAcc** The accumulator Returns **([Buffer](https://nodejs.org/api/buffer.html) | null | [undefined](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/undefined))** A Buffer containing the cleaned response message, or null if no response message, or undefined if the accumulator is incorrect (message length is not valid) ### TransportWebHID **Extends Transport** WebHID Transport implementation #### Parameters * `device` **HIDDevice** #### Examples ```javascript import TransportWebHID from "@ledgerhq/hw-transport-webhid"; ... TransportWebHID.create().then(transport => ...) ``` #### close Release the transport device Returns **[Promise](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Promise)\** #### exchange Exchange with the device using APDU protocol. ##### Parameters * `apdu` **[Buffer](https://nodejs.org/api/buffer.html)** Returns **[Promise](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Promise)<[Buffer](https://nodejs.org/api/buffer.html)>** a promise of apdu response #### isSupported Check if WebUSB transport is supported. #### list List the WebUSB devices that was previously authorized by the user. #### listen Actively listen to WebUSB devices and emit ONE device that was either accepted before, if not it will trigger the native permission UI. Important: it must be called in the context of a UI click! ##### Parameters * `observer` **Observer\>** Returns **Subscription** #### request Similar to create() except it will always display the device permission (even if some devices are already accepted). #### openConnected Similar to create() except it will never display the device permission (it returns a Promise\, null if it fails to find a device). #### open Create a Ledger transport with a HIDDevice ##### Parameters * `device` **HIDDevice**