The Onslip Automation Library

Remote-control any old Android or iOS WebView in a Playwright-inspired way

What it is

This is a small Node.js library that helps you to E2E test/automate/remote-control Android and iOS WebViews, including Capacitor- or Cordova-based applications.

The Onslip Automation API is heavily inspired by Playwright and the aim is to provide a small but still very usable subset of that API. We strive to be as API compatible as we can for the subset that is supported, but since this is a completely separate code base, full compatibility can never be guaranteed.

Now, unlike Playwright's Android support — which requires version 87 or greater of the WebView — this library works with almost any version of the WebView, at least all the way down to the last Crosswalk release (which was based on Chromium 53)[^1]. We use it to automate Crosswalk on Android 4.1 and 6.0 devices, the default system WebView in Android 8 as well as iOS devices running iOS 12.4 and 15.4.

How to use it

First, add this library as a dependency using your favourite package manager:

$ npm install -D @onslip/automation
$ pnpm add -D @onslip/automation
$ yarn add -D @onslip/automation

Second, ensure these dependencies are available:

• Android support requires the adb command to be installed and available in the path.
• iOS support needs ios_webkit_debug_proxy to be running and listening on port 9221. The iOS device management support uses
  • ideviceinstaller to install/uninstall apps;
  • idevicesyslog to read device logs; and
  • ios_instruments_client to start and stop iOS processes.

The first three iOS dependencies can be installed and activated from Homebrew with the following commands. ios_instruments_client must be compiled and copied to the path manually.

$ brew install ios-webkit-debug-proxy libimobiledevice ideviceinstaller
$ ios_webkit_debug_proxy

Finally, try this small example:

const { Device, AndroidDevice, findWebViewContexts, openWebView, pipeline } = require('@onslip/automation');
const { createWriteStream } = require('fs');
const { Readable } = require('stream');

const PROXY_PORT = 8885;

async function main(prog, deviceId) {
    const device = await Device.findDevice(deviceId);

    if (!device) {
        const devices = await Device.findDevices();
        throw `Usage: ${prog} ${devices.map((d) => d.id).join('|') || '<device>'}`;
    }

    console.log(`Checking for debuggable webview on device ${device}`);
    const [ webview ] = await device.findWebViews();

    console.log(`Found webview ${webview}; opening proxy port ${PROXY_PORT}`);
    const options = await device.bindWebView(webview, PROXY_PORT);

    console.log(`Looking for contexts`);
    const [ context ] = await findWebViewContexts(options);

    console.info(`Opening CDP connection via port ${options.port} to context ${context.id} <${context.url}>`);
    const page = await openWebView({...options, ctxId: context.id });

    console.info(`Starting automation of ${webview} on device ${device}`);
    page.setDebug(true);

    try {
        const lollipop = await device.osVersion() >= "5";
        const logLines = device instanceof AndroidDevice
            ? await device.collectLogs({ clear: !lollipop, historic: !lollipop, filterspecs: ['*:D'] })
            : await device.collectLogs();

        const divs = await page.locator('div').count();
        console.log(`There are ${divs} DIV elements in the webview!`);

        await page.locator('body').screenshot({ path: `${deviceId}.png` });
        console.log(`Saved a screenshot to ${deviceId}.png`);

        await pipeline(Readable.from(await logLines()), createWriteStream(`${deviceId}.log`));
        console.log(`Saved device logs to ${deviceId}.log`);
    } finally {
        await page.close();
    }
}

main(...process.argv.slice(1)).catch((err) => (console.error(err), 70)).then(process.exit);

[^1]: Using our fork of Capacitor together with Crosswalk, it's possible to run (and now automate) hybrid applications even on ancient devices running Android 4.1 from 2012.