remote.js

import net from 'net';

import { connectToFirefox as defaultFirefoxConnector } from './rdp-client.js';
import { createLogger } from '../util/logger.js';
import {
  isErrorWithCode,
  RemoteTempInstallNotSupported,
  UsageError,
  WebExtError,
} from '../errors.js';

const log = createLogger(import.meta.url);

// NOTE: this type aliases Object to catch any other possible response.

// Convert a request rejection to a message string.
function requestErrorToMessage(err) {
  if (err instanceof Error) {
    return String(err);
  }
  return `${err.error}: ${err.message}`;
}

export class RemoteFirefox {
  client;
  checkedForAddonReloading;

  constructor(client) {
    this.client = client;
    this.checkedForAddonReloading = false;

    client.on('disconnect', () => {
      log.debug('Received "disconnect" from Firefox client');
    });
    client.on('end', () => {
      log.debug('Received "end" from Firefox client');
    });
    client.on('unsolicited-event', (info) => {
      log.debug(`Received message from client: ${JSON.stringify(info)}`);
    });
    client.on('rdp-error', (rdpError) => {
      log.debug(`Received error from client: ${JSON.stringify(rdpError)}`);
    });
    client.on('error', (error) => {
      log.debug(`Received error from client: ${String(error)}`);
    });
  }

  disconnect() {
    this.client.disconnect();
  }

  async addonRequest(addon, request) {
    try {
      const response = await this.client.request({
        to: addon.actor,
        type: request,
      });
      return response;
    } catch (err) {
      log.debug(`Client responded to '${request}' request with error:`, err);
      const message = requestErrorToMessage(err);
      throw new WebExtError(`Remote Firefox: addonRequest() error: ${message}`);
    }
  }

  async getAddonsActor() {
    try {
      // getRoot should work since Firefox 55 (bug 1352157).
      const response = await this.client.request('getRoot');
      if (response.addonsActor == null) {
        return Promise.reject(
          new RemoteTempInstallNotSupported(
            'This version of Firefox does not provide an add-ons actor for ' +
              'remote installation.',
          ),
        );
      }
      return response.addonsActor;
    } catch (err) {
      // Fallback to listTabs otherwise, Firefox 49 - 77 (bug 1618691).
      log.debug('Falling back to listTabs because getRoot failed', err);
    }

    try {
      const response = await this.client.request('listTabs');
      // addonsActor was added to listTabs in Firefox 49 (bug 1273183).
      if (response.addonsActor == null) {
        log.debug(
          'listTabs returned a falsey addonsActor: ' +
            `${JSON.stringify(response)}`,
        );
        return Promise.reject(
          new RemoteTempInstallNotSupported(
            'This is an older version of Firefox that does not provide an ' +
              'add-ons actor for remote installation. Try Firefox 49 or ' +
              'higher.',
          ),
        );
      }
      return response.addonsActor;
    } catch (err) {
      log.debug('listTabs error', err);
      const message = requestErrorToMessage(err);
      throw new WebExtError(`Remote Firefox: listTabs() error: ${message}`);
    }
  }

  async installTemporaryAddon(addonPath, openDevTools) {
    const addonsActor = await this.getAddonsActor();

    try {
      const response = await this.client.request({
        to: addonsActor,
        type: 'installTemporaryAddon',
        addonPath,
        openDevTools,
      });
      log.debug(`installTemporaryAddon: ${JSON.stringify(response)}`);
      log.info(`Installed ${addonPath} as a temporary add-on`);
      return response;
    } catch (err) {
      const message = requestErrorToMessage(err);
      throw new WebExtError(`installTemporaryAddon: Error: ${message}`);
    }
  }

  async getInstalledAddon(addonId) {
    try {
      const response = await this.client.request('listAddons');
      for (const addon of response.addons) {
        if (addon.id === addonId) {
          return addon;
        }
      }
      log.debug(
        `Remote Firefox has these addons: ${response.addons.map((a) => a.id)}`,
      );
      return Promise.reject(
        new WebExtError(
          'The remote Firefox does not have your extension installed',
        ),
      );
    } catch (err) {
      const message = requestErrorToMessage(err);
      throw new WebExtError(`Remote Firefox: listAddons() error: ${message}`);
    }
  }

  async checkForAddonReloading(addon) {
    if (this.checkedForAddonReloading) {
      // We only need to check once if reload() is supported.
      return addon;
    } else {
      const response = await this.addonRequest(addon, 'requestTypes');

      if (response.requestTypes.indexOf('reload') === -1) {
        const supportedRequestTypes = JSON.stringify(response.requestTypes);
        log.debug(`Remote Firefox only supports: ${supportedRequestTypes}`);
        throw new UsageError(
          'This Firefox version does not support add-on reloading. ' +
            'Re-run with --no-reload',
        );
      } else {
        this.checkedForAddonReloading = true;
        return addon;
      }
    }
  }

  async reloadAddon(addonId) {
    const addon = await this.getInstalledAddon(addonId);
    await this.checkForAddonReloading(addon);
    await this.addonRequest(addon, 'reload');
    process.stdout.write(
      `\rLast extension reload: ${new Date().toTimeString()}`,
    );
    log.debug('\n');
  }
}

// Connect types and implementation

export async function connect(
  port,
  { connectToFirefox = defaultFirefoxConnector } = {},
) {
  log.debug(`Connecting to Firefox on port ${port}`);
  const client = await connectToFirefox(port);
  log.debug(`Connected to the remote Firefox debugger on port ${port}`);
  return new RemoteFirefox(client);
}

// ConnectWithMaxRetries types and implementation

export async function connectWithMaxRetries(
  // A max of 250 will try connecting for 30 seconds.
  { maxRetries = 250, retryInterval = 120, port },
  { connectToFirefox = connect } = {},
) {
  async function establishConnection() {
    var lastError;

    for (let retries = 0; retries <= maxRetries; retries++) {
      try {
        return await connectToFirefox(port);
      } catch (error) {
        if (isErrorWithCode('ECONNREFUSED', error)) {
          // Wait for `retryInterval` ms.
          await new Promise((resolve) => {
            setTimeout(resolve, retryInterval);
          });

          lastError = error;
          log.debug(
            `Retrying Firefox (${retries}); connection error: ${error}`,
          );
        } else {
          log.error(error.stack);
          throw error;
        }
      }
    }

    log.debug('Connect to Firefox debugger: too many retries');
    throw lastError;
  }

  log.debug('Connecting to the remote Firefox debugger');
  return establishConnection();
}

export function findFreeTcpPort() {
  return new Promise((resolve) => {
    const srv = net.createServer();
    srv.listen(0, '127.0.0.1', () => {
      const freeTcpPort = srv.address().port;
      srv.close(() => resolve(freeTcpPort));
    });
  });
}