dualsense-ts/src/hid/web_hid_provider.ts

A natural interface for your DualSense controller, with Typescript

import { ByteArray } from "./byte_array";
import { HIDProvider, DualsenseHIDState } from "./hid_provider";

export class WebHIDProvider extends HIDProvider {
  public device?: HIDDevice;
  public wireless?: boolean;
  public buffer?: DataView;

  constructor() {
    super();
    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
    if (!navigator.hid) throw new Error("WebHID not supported by this browser");

    navigator.hid.addEventListener("disconnect", ({ device }) => {
      if (device === this.device) {
        this.device = undefined;
        this.disconnect();
      }
    });
    navigator.hid.addEventListener("connect", ({ device }) => {
      if (!this.device) this.attach(device);
    });
  }

  /**
   * WebHID API doesn't indicate whether we are connected through the controller's
   * USB or Bluetooth interface. The protocol is different depending on the connection
   * type so we will try to detect it based on the collection information.
   */
  detectConnectionType(): void {
    this.wireless = undefined;
    if (!this.device) {
      return;
    }

    for (const c of this.device.collections) {
      if (
        c.usagePage !== HIDProvider.usagePage ||
        c.usage !== HIDProvider.usage
      ) {
        continue;
      }

      // Compute the maximum input report byte length and compare against known values.
      const maxInputReportBytes = (c.inputReports ?? []).reduce(
        (max, report) => {
          return Math.max(
            max,
            (report.items ?? []).reduce((sum, item) => {
              return sum + (item.reportSize ?? 0) * (item.reportCount ?? 0);
            }, 0)
          );
        },
        0
      );

      if (maxInputReportBytes == 504) {
        this.wireless = false;
      } else if (maxInputReportBytes == 616) {
        this.wireless = true;
      }
    }
  }

  attach(device: HIDDevice): void {
    device
      .open()
      .then(() => {
        this.device = device;
        this.detectConnectionType();

        // Enable accelerometer, gyro, touchpad
        return this.device.receiveFeatureReport(0x05);
      })
      .then(() => {
        if (!this.device) throw Error("Controller disconnected before setup");
        this.device.addEventListener("inputreport", ({ reportId, data }) => {
          this.buffer = data;
          this.onData(this.process({ reportId, buffer: data }));
        });
      })
      .catch((err: Error) => {
        this.onError(err);
        this.disconnect();
      });
  }

  /**
   * You need to get HID device permissions from an interactive
   * component, like a button. This returns a callback for triggering
   * the permissions request.
   */
  getRequest(): () => Promise<unknown> {
    return () =>
      navigator.hid
        .requestDevice({
          filters: [
            {
              vendorId: HIDProvider.vendorId,
              productId: HIDProvider.productId,
              usagePage: HIDProvider.usagePage,
              usage: HIDProvider.usage,
            },
          ],
        })
        .then((devices: HIDDevice[]) => {
          if (devices.length === 0) {
            return this.onError(new Error(`No controllers available`));
          }
          this.attach(devices[0]);
        })
        .catch((err: Error) => {
          this.onError(err);
        });
  }

  connect(): void {
    // Nothing to be done.
  }

  get connected(): boolean {
    return this.device !== undefined;
  }

  disconnect(): void {
    if (this.device) {
      this.device.close().finally(() => this.reset());
    } else {
      this.reset();
    }
  }

  async write(data: Uint8Array): Promise<void> {
    if (!this.device) return;
    return this.device.sendFeatureReport(0, data);
  }

  process({
    reportId,
    buffer,
  }: {
    reportId: number;
    buffer: DataView;
  }): DualsenseHIDState {
    // DataView does not report the first byte (the report id), we simulate it
    const report: ByteArray = {
      length: buffer.byteLength + 1,
      readUint8(offset) {
        return offset > 0 ? buffer.getUint8(offset - 1) : reportId;
      },
      readUint16LE(offset) {
        return offset > 0
          ? buffer.getUint16(offset - 1, true)
          : (reportId << 8) | buffer.getUint8(0);
      },
    };

    return this.processReport(report);
  }
}