Simon Willison’s Weblog

simonepri/geo-maps. Neat project which publishes GeoJSON maps of the world automatically derived from OpenStreetMap. Three variants are available: country political maritime boundaries, country political coastline boundaries and a general outline of the world’s land territories.

# 4:06 pm / geojson, gis, openstreetmap

gzthermal-web (via) I built a quick web application wrapping the gzthermal gzip visualization tool and deployed it to Zeit Now wrapped up in a Docker container. Give it a URL and it shows you a PNG visualization of how gzip encodes that page.

# 6:24 pm / zeit-now, projects, docker, sanic

Run the First Edition of Unix (1972) with Docker (via) This is so cool... just run “docker run --rm -it bahamat/unix-1st-ed” to drop into a simulation of a PDP-11 running genuine 1972 era Unix! If you haven’t got into Docker yet, Docker for Mac is a single click install these days and works incredibly well.

# 3:36 pm / docker, unix

From Markdown to RCE in Atom (via) Lukas Reschke found a remote code execution vulnerability in the Atom editor by taking advantage of a combination of Markdown’s ability to embed HTML, Atom’s Content-Security-Policy allowing JavaScript from the local filesystem to be executed, and a test suite HTML file hidden away in the Atom application package that executes code passed to it via query string.

# 4:13 pm / xss, security

How a single PostgreSQL config change improved slow query performance by 50x. “If you are using SSDs and running PostgreSQL with default configuration, I encourage you to try tuning random_page_cost & seq_page_cost. You might be surprised by some huge performance improvements.”

# 8:11 pm / postgresql

Return of the Obra Dinn: Dithering Process (via) Lucas Pope (creator of “Papers, Please”) has a new game under development: “Return of the Obra Dinn”, a first-person adventure mystery game set in 1807 that is spectacularly rendered in a 1-bit art style. He has a development diary on tigsource.com, and in this entry he describes the extreme lengths he has gone to in order to develop the best possible dithering implementation for rendering his 3D world in 1-bit colour. “It feels a little weird to put 100 hours into something that won’t be noticed by its absence.”

# 9:21 pm / games, game-design

TLDR pages. This is an absurdly good idea: a community maintained set of alternative man pages for common commands with a focus on usage examples, plus a “tldr netstat” command to see them. The man pages themselves are maintained on GitHub.

# 5:38 am / linux, documentation, github

VoxelSpace (via) Lovely clear explanation of the voxel space landscape rendering technique used by NovaLogic for Comanche back in 1992, including a working JavaScript demo plus pseudo-code in Python.

# 7:30 pm / canvas, javascript

What is the plural of blitz? Wow, WordHippo is a straight up masterclass in keyword SEO tactics. Everything from the page URL to the keyword-crammed content to the enormous quantity of related links.

# 5:42 pm / seo

harelba/q (via) q is a neat command-line utility that lets you run SQL queries directly against CSV and TSV files. Internally it works by firing up an in-memory SQLite database, and as of the latest release (1.7.1) you can use the new --save-db-to-disk option to save that in-memory database to disk.

# 5:49 pm / csv, sqlite

Added TSV example to the README · simonw/csvs-to-sqlite@957d4f5. Thanks to a pull request from Jani Monoses, csvs-to-sqlite can now handle TSV (or any other separator) as well as regular CSVs.

# 7:02 am / csv

SQLite Query Language: WITH clause. SQLite’s documentation on recursive CTEs starts out with some nice clear examples of tree traversal using a WITH statement, then gets into graphs, then goes way off the deep end with a Mandelbrot Set query and a query that can solve Soduku puzzles (“in less than 300 milliseconds on a modern workstation”).

# 7:23 am / sql, sqlite

Many Small Queries Are Efficient In SQLite. Since SQLite runs in-process rather than being accessed over a network it avoids the per-query overhead of network round trips. This means that while MySQL or PostgreSQL applications need to avoid N+1 query patterns that create 100s of queries per request, SQLite apps can be designed differently: provided you hit indexes or small tables, 200 queries just means 200 extra cheap function calls.

# 4:24 pm / performance, sqlite

A Complete CMS with No Server and 18 Lines of Code | Netlify. Slightly hyperbolic title, but there’s something really interesting going on here. Netlify is a CDN/hosting provider optimized for static site builders—it can hook up to a GitHub repository and build and deploy your site on every commit. Netlify CMS is their open-source CMS tool which works in a fascinating way: it’s a single page React app which stores structured content (as Markdown files with embedded key/value pairs) directly to your GitHub repository. Fire up Chrome DevTools and you can watch it using the GitHub API to construct new commits every time you hit “save”.

# 5:53 pm / cms, github, react

Inside Docker’s “FROM scratch” (via) I’m a big fan of understanding your abstractions. Here’s a neat tutorial that dives deep into Docker’s “scratch” image which offers the smallest possible Docker image, and hence provides a great opportunity to understand what a Docker container at its most minimal does for you.

# 4:33 pm / docker

The Best Request Is No Request, Revisited · An A List Apart Article. In HTTP/2 the rules have changed: serving unnecessary code as part of a larger bundle to avoid extra request overhead no longer makes sense. Splitting your code into many files and loading just the ones needed by the current page can knock seconds off your load time.

# 3:50 pm / http2, web-performance

Firefox Debugger Playground. Excellent hands-on tutorial to using the Firefox JavaScript debugger. I learned a bunch of neat tricks from this—including using conditional breakpoints to add temporary console.log statements—since that function returns undefined it won’t pause your code, but this saves you from having to remember to remove the lines from your source code later. I also didn’t know that the Firefox debugger can show the value of variables in paused code if you hover over them in the source pane. [UPDATE: Turns out Chrome DevTools do this as well—TIL]

# 4:01 pm / debuggers, firefox, javascript

Boiling the Ocean, Incrementally—How Stylo Brought Rust and Servo to Firefox. Firefox Quantum is the product of an impressive, highly risky chain of software engineering—Rust, Servo, then Stylo.

# 8:34 pm / rust, firefox, servo

Big Data Workflow with Pandas and SQLite (via) Handy tutorial on dealing with larger data (in this case a 3.9GB CSV file) by incrementally loading it into pandas and writing it out to SQLite.

# 11:02 pm / pandas, csv, sqlite

Object models (via) Extremely comprehensive and readable discussion of the object models of Python, JavaScript, Lua and Perl 5. I learned something new about every one of those languages.

# 2:59 pm / perl, python, javascript, oop, lua

Interactive Workflows for C++ with Jupyter. Whoa, this really works... not just an interactive C++ REPL in a Jupyter notebook, but inline graph plotting support and interactive widgets as well. Scroll to the bottom of the article for Binder links which let you fire up an interactive C++ REPL in your browser and start interacting with it instantly.

# 9:51 pm / jupyter, c-plus-plus

Can I use... input type=color. TIL <input type="color"> has reached 78.83% support globally already - biggest gap right now is Mobile Safari.

# 9:56 pm / html

Datasette: Ability to customize presentation of specific columns in HTML view. Still a work in progress, but Datasette master now allows you to inject links to one or more additional CSS and JavaScript resources (optionally with SRI hashes) which will be included on every page. Each template also
now provides CSS classes on the body element derived from the current database and table names to provide hooks for custom styling. Next up: custom template support.

# 7:27 am / css, datasette, paul-ford