A presentation at Render Conf in in Oxford, UK by Yonatan Mevorach
DEVTOOLS & HEADLESS CHROME: THE AUTOMATION POWER-COUPLE
Yonatan Mevorach @cowchimp
Web Automation youtu.be/fsF7enQY8uI
”I can’t automate this” -- no one ever (after watching this talk)
Headless Browsers cbnd flic.kr/p/qnSPdN
Chrome
headless Chrome
[ { { { { { { { { { { { { { { { { { { { { { ] time: time: time: time: time: time: time: time: time: time: time: time: time: time: time: time: time: time: time: time: time: "08:00", "09:00", "09:10", "09:40", "10:10", "10:40", "11:10", "11:30", "11:50", "12:20", "12:40", "13:40", "13:55", "14:10", "14:25", "14:55", "15:25", "15:55", "16:35", "17:15", "17:25", title: title: title: title: title: title: title: title: title: title: title: title: title: title: title: title: title: title: title: title: title: "Registration and breakfast" }, "Welcome" }, "A CSS Carol" }, "Talk details coming soon" }, "Common ways we break accessibility and how to avoid them" }, "Refreshments" }, "DevTools and Headless Chrome - The Automation Power-Couple" }, "Reducing the friction of online payments" }, "How to hack a web app?" }, "Teach Your Bundler The Users' Habits" }, "Lunch" }, "Creating IoT applications with Web Bluetooth" }, "Escaping the Sandbox with Puck.js" }, "Physical interfaces for digital applications" }, "Let's Get Chatty with Conversational Interface in JavaScript" }, "WebAssembly as cross-platform architecture?!" }, "Refreshments" }, "Data Sketches | A year of exotic data visualizations" }, "Serving for the win - Deploys and hosting for the rest of us" }, "Closing remarks" }, "After Party" }
Chrome DevTools
protocol Chrome DevTools
DevTools Embedding Frontendapp WebSockets ChromeAPI Headless Adapted from content by © Sami Kyöstilä, Google goo.gl/yQi9kZ
{ id: 1, method: "Runtime.evaluate", params: { expression: "1 + 1" } } DevTools Embedding Frontendapp ChromeAPI Headless Adapted from content by © Sami Kyöstilä, Google goo.gl/yQi9kZ
{ id: 1, method: "Runtime.evaluate", params: { expression: "1 + 1" } } DevTools Embedding Frontendapp ChromeAPI Headless { id: 1, result: { result: { type: "number", value: 2, description: "2" }, wasThrown: false } } Adapted from content by © Sami Kyöstilä, Google goo.gl/yQi9kZ
DevTools Embedding client app DevTools Headlesstarget API Adapted from content by © Sami Kyöstilä, Google goo.gl/yQi9kZ
node --inspect index.js
headless protocol
chrome --headless --remote-debugging-port=9222 https://2018.render-conf.com
chrome --headless --remote-debugging-port=9222 https://2018.render-conf.com
chrome --headless --remote-debugging-port=9222 https://2018.render-conf.com
chrome --headless --remote-debugging-port=9222 https://2018.render-conf.com
chrome --headless --remote-debugging-port=9222 https://2018.render-conf.com
tinyurl.com/ headless-talk @cowchimp blog.cowchimp.com
In this talk we'll see what problems we can fix (or better yet, avoid) by combining two things developers love: Chrome DevTools and automating repetitive tasks.
To do this we'll use a new capability introduced in Chrome 59: running Chrome in "Headless Mode".
First off we'll show the powers of each of these tools separately. We'll use DevTools to debug other platforms like node.js and iOS, and we'll use Chrome in Headless Mode to do things like take screenshots, and to scrape sites for data.
Then we'll explore how by combining the two you can make DevTools work for you around-the-clock. We'll cover how to run tests, and set up automatic alerts to catch bugs in your code. We'll also find out how to avoid performance degradation by monitoring everything about your app (amount of unused CSS, memory footprint, etc.)
for free. You
can too.