Simon Willison’s Weblog

gifcap (via) This is really neat: a purely client-side implementation of animated gif screen capture, using navigator.mediaDevices.getDisplayMedia for the screen capturing, mithril for the UI and the gif.js pure JavaScript GIF encoding library to render the output. # 30th March 2020, 9:29 pm

PostGraphile: Production Considerations. PostGraphile is a tool for building a GraphQL API on top of an existing PostgreSQL schema. Their “production considerations” documentation is particularly interesting because it directly addresses some of my biggest worries about GraphQL: the potential for someone to craft an expensive query that ties up server resources. PostGraphile suggests a number of techniques for avoiding this, including a statement timeout, a query allowlist, pagination caps and (in their “pro” version) a cost limit that uses a calculated cost score for the query. # 27th March 2020, 1:22 am

Making Datasets Fly with Datasette and Fly (via) It’s always exciting to see a Datasette tutorial that wasn’t written by me! This one is great—it shows how to load Central Park Squirrel Census data into a SQLite database, explore it with Datasette and then publish it to the Fly hosting platform using datasette-publish-fly and datasette-cluster-map. # 26th March 2020, 11:56 pm

hacker-news-to-sqlite (via) The latest in my Dogsheep series of tools: hacker-news-to-sqlite uses the Hacker News API to fetch your comments and submissions from Hacker News and save them to a SQLite database. # 21st March 2020, 4:27 am

Django: Added support for asynchronous views and middleware (via) An enormously consequential feature just landed in Django, and is set to ship as part of Django 3.1 in August. Asynchronous views will allow Django applications to define views using “async def myview(request)”—taking full advantage of Python’s growing asyncio ecosystem and providing enormous performance improvements for Django sites that do things like hitting APIs over HTTP. Andrew has been puzzling over this for ages and it’s really exciting to see it land in a form that should be usable in a stable Django release in just a few months. # 19th March 2020, 3:43 am

datasette-publish-fly (via) Fly is a neat new Docker hosting provider with a very tempting pricing model: Just $2.67/month for their smallest always-on instance, and they give each user $10/month in free credit. datasette-publish-fly is the first plugin I’ve written using the publish_subcommand plugin hook, which allows extra hosting providers to be added as publish targets. Install the plugin and you can run “datasette publish fly data.db” to deploy SQLite databases to your Fly account. # 19th March 2020, 3:40 am

New governance model for the Django project. This has been under discussion for a long time: I’m really excited to see it put into action. It’s difficult to summarize, but they key effect should be a much more vibrant, active set of people involved in making decisions about the framework. # 12th March 2020, 5:27 pm

Announcing Daylight Map Distribution. Mike Migurski announces a new distribution of OpenStreetMap: a 42GB dump of the version of the data used by Facebook, carefully moderated to minimize the chance of incorrect or maliciously offensive edits. Lots of constructive conversation in the comments about the best way for Facebook to make their moderation decisions more available to the OSM community. # 12th March 2020, 11:44 am

The unexpected Google wide domain check bypass (via) Fantastic story of discovering a devious security vulnerability in a bunch of Google products stemming from a single exploitable regular expression in the Google closure JavaScript library. # 9th March 2020, 11:27 pm

Millions of tiny databases. Fascinating, detailed review of a paper that describes Amazon’s Physalia, a distributed configuration store designed to provide extremely high availability coordination for Elastic Block Store replication. My eyebrows raised at “Physalia is designed to offer consistency and high-availability, even under network partitions.” since that’s such a blatant violation of CAP theorem, but it later justifies it like so: “One desirable property therefore, is that in the event of a partition, a client’s Physalia database will be on the same side of the partition as the client. Clever placement of cells across nodes can maximise the chances of this.” # 5th March 2020, 4:37 am