Simon Willison’s Weblog

Calling C functions from BigQuery with web assembly (via) Google BigQuery lets you define custom SQL functions in JavaScript, and it turns out they expose the WebAssembly.instantiate family of APIs. Which means you can write your UDD in C or Rust, compile it to WebAssembly and run it as part of your query! # 27th October 2019, 5:55 am

Azure Readiness Checklist (via) I love a good comprehensive checklist. This one is focused on large projects running on Azure but it’s still fun to browse through if you are hosting elsewhere, mainly as a reminder of quite how much still goes into deploying large web services into production. # 26th October 2019, 8:32 pm

kepler.gl. Uber built this open source geospatial analysis tool for large-scale data sets, and they offer it as a free hosted online tool—just click Get Started on the site. I uploaded two CSV files with 30,000+ latitude/longitude points in them just now and used Kepler to render them as images. # 25th October 2019, 4:16 am

Thematic map—GIS Wiki. This is a really useful wiki full of GIS information, and the coverage of different types of thematic maps is particularly thorough. # 21st October 2019, 2:25 am

Setting up Datasette, step by step (via) Tobias describes how he runs Datasette on his own server/VPS, using nginx and systemd. I’m doing something similar for some projects and systemd really does feel like the solution to the “ensure a Python process keeps running” problem I’ve been fighting for over a decade. I really like how Tobias creates a dedicated Linux user for each of his deployed Python projects. # 21st October 2019, 2:20 am

2018 Central Park Squirrel Census in Datasette (via) The Squirrel Census project released their data! 3,000 squirrel observations in Central Park, each with fur color and latitude and longitude and behavioral observations. I love this data so much. I’ve loaded it into a Datasette running on Glitch. # 16th October 2019, 6:01 pm

μPlot (via) “An exceptionally fast, tiny time series chart. [...] from a cold start it can create an interactive chart containing 150,000 data points in 40ms. [...] at < 10 KB, it’s likely the smallest and fastest time series plotter that doesn’t make use of WebGL shaders or WASM” # 14th October 2019, 11:03 pm

goodreads-to-sqlite (via) This is so cool! Tobias Kunze built a Python CLI tool to import your Goodreads data into a SQLite database, inspired by github-to-sqlite and my various other Dogsheep tools. It’s the first Dogsheep style tool I’ve seen that wasn’t built by me—and Tobias’ write-up includes some neat examples of queries you can run against your Goodreads data. I’ve now started using Goodreads and I’m importing my books into my own private Dogsheep Datasette instance. # 14th October 2019, 4:07 am

SQL Murder Mystery in Datasette (via) “A crime has taken place and the detective needs your help. The detective gave you the  crime scene report, but you somehow lost it. You vaguely remember that the crime  was a murder that occurred sometime on ​Jan.15, 2018 and that it took place in SQL  City. Start by retrieving the corresponding crime scene report from the police  department’s database.”—Really fun game to help exercise your skills with SQL by the NU Knight Lab. I loaded their SQLite database into Datasette so you can play in your browser. # 7th October 2019, 11:37 pm

twitter-to-sqlite 0.6, with track and follow. I shipped a new release of my twitter-to-sqlite command-line tool this evening. It now includes experimental features for subscribing to the Twitter streaming API: you can track keywords or follow users and matching Tweets will be written to a SQLite database in real-time as they come in through the API. Since Datasette supports mutable databases now you can run Datasette against the database and run queries against the tweets as they are inserted into the tables. # 6th October 2019, 4:54 am

Streamlit: Turn Python Scripts into Beautiful ML Tools (via) A really interesting new tool / application development framework. Streamlit is designed to help machine learning engineers build usable web frontends for their work. It does this by providing a simple, productive Python environment which lets you declaratively build up a sort-of Notebook style interface for your code. It includes the ability to insert a DataFrame, geospatial map rendering, chart or image into the application with a single Python function call. It’s hard to describe how it works, but the tutorial and demo worked really well for me: “pip install streamlit” and then “streamlit hello” to get a full-featured demo in a browser, then you can run through the tutorial to start building a real interactive application in a few dozen lines of code. # 6th October 2019, 3:52 am

Get your own Pocket OAuth token (via) I hate it when APIs make you jump through extensive hoops just to get an access token for pulling data directly from your own personal account. I’ve been playing with the Pocket API today and it has a pretty complex OAuth flow, so I built a tiny Flask app on Glitch which helps go through the steps to get an API token for your own personal Pocket account. # 5th October 2019, 9:56 pm

Client-Side Certificate Authentication with nginx. I’m intrigued by client-side browser certificates, which allow you to lock down a website such that only browsers with a specific certificate installed can access them. They work on both laptops and mobile phones. I followed the steps in this tutorial and managed to get an nginx instance running which only allows connections from my personal laptop and iPhone. # 5th October 2019, 5:26 pm

NGINX: Authentication Based on Subrequest Result (via) TIL about this neat feature of NGINX: you can use the auth_request directive to cause NGINX to make an HTTP subrequest to a separate authentication server for each incoming HTTP request. The authentication server can see the cookies on the incoming request and tell NGINX if it should fulfill the parent request (via a 2xx status code) or if it should be denied (by returning a 401 or 403). This means you can run NGINX as an authenticating proxy in front of any HTTP application and roll your own custom authentication code as a simple webhook-recieving endpoint. # 4th October 2019, 3:36 pm

SQL queries don’t start with SELECT. This is really useful. Understanding that SELECT (and associated window functions) happen after the WHERE, GROUP BY and HAVING helps explain why you can’t filter a query based on the results of a window function for example. # 3rd October 2019, 8:56 pm