Simon Willison’s Weblog

egghead screencasting technical guide (via) Detailed guide to producing high quality screencasts—software to use, audio tips, editing workflow—from the egghead.io online instructor platform.

# 5:39 pm / screencasting

Introducing Partytown 🎉: Run Third-Party Scripts From a Web Worker (via) This is just spectacularly clever. Partytown is a 6KB JavaScript library that helps you move gnarly poorly performing third-party scripts out of your main page and into a web worker, so they won’t destroy your page performance. The really clever bit is in how it provides sandboxed access to the page DOM: it uses a devious trick where a proxy object provides getters and setters which then make blocking API calls to a separate service worker, using the mostly-forgotten xhr.open(..., false) parameter that turns off the async default for an XMLHttpRequest call.

# 6:29 pm / async, javascript, webworkers, serviceworkers

File not found: A generation that grew up with Google is forcing professors to rethink their lesson plans (via) This is fascinating: as-of 2017 university instructors have been increasingly encountering students who have absolutely no idea how files and folders on a computer work. The new generation has a completely different mental model of how applications work, where everything is found using search and data mostly lives inside the application that you use to manipulate it.

Gradually, Garland came to the same realization that many of her fellow educators have reached in the past four years: the concept of file folders and directories, essential to previous generations’ understanding of computers, is gibberish to many modern students.

# 10:49 pm / teaching, usability, computer-literacy

New tool: an nginx playground. Julia Evans built a sandbox tool for interactively trying out an nginx configuration and executing test requests through it. I love this kind of tool, and Julia’s explanation of how they built it using a tiny fly.io instance and a network namespace to reduce the amount of damage any malicious usage could cause is really interesting.

# 6:44 pm / nginx, security, julia-evans, fly

django-upgrade (via) Adam Johnson’s new CLI tool for upgrading Django projects by automatically applying changes to counter deprecations made in different versions of the framework. Uses the Python standard library tokenize module which gives it really quick performance in parsing and rewriting Python code. Exciting to see this kind of codemod approach becoming more common in Python world—JavaScript developers use this kind of thing a lot.

# 5:42 am / cli, django, python, adam-johnson

The GIL and its effects on Python multithreading (via) Victor Skvortsov presents the most in-depth explanation of the Python Global Interpreter Lock I’ve seen anywhere. I learned a ton from reading this.

# 5:23 pm / concurrency, gil, python, threads