Articles

The Star-Spangled Ballad

If you listen carefully to the Ballad of Willie Watkins, you might hear another song peeking through.

flapi.sh: a tiny command-line tool for experimenting with the Flickr API

Combining several existing tools to make something that allows for quick experiments and exploration.

The new Flickr Commons Explorer

A new way to browse the photos in the Flickr Commons programme.

Monki Gras 2024: Step… Step… Step…

Swing dancing and prompt engineering are pretty different. But could learning one help us learn the other?

Moving my YouTube Likes from one account to another

Some experimenting with the YouTube API to merge two accounts into one.

Making a PDF that’s larger than Germany

We’re gonna need a bigger printer.

The Collected Works of Ian Flemingo

A fledgling author uses a theatre trip to leave the nest. (Or: some props I made for a cosplay event.)

What mammal is that?

In which Apple Photos accidentally tells me about a cool new animal.

My favourite books from 2023

Storms and schools, escapes and exorcisms, murders and magic – what I enjoyed reading this year.

Getting the path to the note I have open in Obsidian

Although Obsidian doesn’t support AppleScript, I can use System Events to find out which note I have open.

Setting up Fish to make virtualenv easier

I wrote some shell config to smooth out the experience of using virtual environments in Python.

Telling mechanize how to find local issuer certificates

Fixing the “unable to get local issuer certificate” error when using mechanize.Browser.

Making the fish shell more forgetful

A few commands that help me keep unwanted entries out of my shell’s autocomplete.

Hyperfocus and hobbies

The power of ADHD-associated hyperfocus and how I’ve become wary of feeding it too often.

Finding the biggest items in my Photos Library

A quick script to help move the biggest items out of my main Photos Library.

Spotting spam in our CloudFront logs

Looking for search queries that came from robots, not real people.

Adding locations to my photos from my Apple Watch workouts

My Apple Watch knows where I am, which is handy when I have a camera that doesn’t.

Fare-Wellcome Collection

After nearly seven years, it’s time for something new.

How I set up my Obsidian vaults

The tags, folders, and themes I use to manage information in my Obsidian vaults.

Finding a mystery IAM access key

Using the GetAccessKeyInfo and GetAccessKeyLastUsed APIs can help us trace an IAM key back to its source.

A blue plaque for Hester

Making a small memorial to a forgotten secretary who helped pull off one of the most daring deceptions of WWII.

Tag your infrastructure-as-code resources with a link to their definitions

Applying a default tag that points to the IaC definition makes it easy to go from the console to the code.

Parsing CloudFront logs with Python

A couple of functions I use to get access to CloudFront logs as easy-to-use iterators.

My Python snippet for walking a file tree

A function to find all the files in a directory is one of my most-used snippets.

My custom <picture> plugin for Jekyll

How I make images that load quickly and look good for readers, and which are easy for me to manage.

Spy for Spy

A two-handed sapphic romance with a clever narrative twist makes for a compelling and thoughtful new play.

Turning off ECS tasks overnight using an EventBridge Schedule

Calling the UpdateService API on a fixed schedule allows us to turn services off in the evening, and back on again the next morning.

Preserving Dates during JSON serialisation with vanilla JS

How to make sure you get a Date back when you call JSON.parse and JSON.stringify.

Writing a Mac app to review my photos

Dipping my toes into SwiftUI to make a tool for reviewing my photos with just the keyboard.

Have a single definition of “now”

Having one function that you always use to get the current time is super handy when debugging issues that only occur at specific times.

Starting Docker just before I need it

I don’t keep Docker running all the time, but intercepting the docker command means it’s always running when I need it.

Snippets to manage albums in Photos.app

AppleScript only allows us to add photos to an album; dipping into Swift and PhotoKit lets us both add and remove photos.

s3tree: viewing a tree of objects in S3 in my terminal

A script to give me a quick overview of some objects in a hierarchical view.

Redecorating my bedroom

Splashing some sunshine in the space where I sleep.

Getting alerts about flaky ECS tasks in Slack

When ECS is “unable to consistently start tasks successfully”, we get a Slack alert that tells us to investigate.

Using templates in Terraform to document a deployment

Terraform can fill in placeholders with exact values from your deployment, for easy copy/paste instructions.

Publishing lots and lots of messages to SNS

Careful use of the PublishBatch API makes it quick and easy for me to send thousands of messages into SNS.

Filtering AWS CLI output by tags using jq

Using from_entries is a nicer way to deal with the list of Name/Value pairs returned by the AWS CLI.

Cats, cross-stitch, and copyright

In celebration of my favourite apex predator.

Filtering out bogus requests from Netlify Analytics

Using redirects to filter out bots trying to hack my non-existent PHP installation.

Creating a Python dictionary with multiple, equivalent keys

Using collections.UserDict, we can create a dictionary where dict[key1] and dict[key2] always point to the same value.

Splitting a class into balanced groups

How do you make sure everyone gets to work with everyone else?

Testing JavaScript without a (third-party) framework

The browser can be a pretty good place to run your JavaScript tests.

CSS formatting in the console

Did you know you can use %c to format your console.log messages?

Going through my old school papers

Digitising and pruning my boxes of paper from school. In which I have nostalgia, sadness, and the sense that everything old is new again.

A Python function to iterate through an S3 Bucket Inventory

Getting something that looks more like the output of the ListObjectsV2 API.

How moving to the cloud took our digital collections to new heights

Building our own platform allowed us to make decisions based on what’s best for the collections, and not the limitations of our digital infrastructure.

A bookmarklet to show which responsive image was chosen

Debugging my <picture> and <source> tags.

Changing the bulb in a Meridian Lighting CIR100B ceiling light

A note to my future self. Also, reverse image search is amazing.

Beware of transparent backgrounds when using AVIF with ImageMagick 6

You probably want to use version 7.

Upward assignment in Ruby

A deep dive into the internals of Ruby and metaprogramming techniques, in a quest for a cursed operator.

My favourite books from 2022

Romance and rust, gender and grief, horror and the House – what I enjoyed reading this year.

A script to get Live Text from images

Using Apple’s built-in tools to get OCR text from an image, but without going through a GUI.

Getting an Important Internet Checkmark to follow your cursor

Party like it’s 1996! A trailing checkmark cursor will make your Brand Website feel fun and authentic.

How we do bulk analysis of our Prismic content

By downloading all our Prismic documents, we can run validation rules, fix broken links, and find interesting examples.

Launching a rocket in the worst possible way

Taking the humble <marquee> tag where no HTML tag has gone before.

Getting the base directory of an sbt project

Some notes on printing sbt settings, so you can use them as the input to another script.

Redacting sensitive query parameters with koa and koa-logger

Using a custom transporter to modify the log message and remove secret information.

A day out at the Bure Valley Railway

My photos from a delightful day on a steam railway with smol trains.

Changing the macOS accent colour without System Preferences

Updating the accent colour everywhere, with immediate effect, using a script written in Swift.

Ten years of blogging

A decade ago, I registered a domain and started writing.

Saving your alt text from Twitter

Twitter’s archives don’t include the alt text you wrote on images, but you can save a copy with their API.

A simple gallery plugin for Obsidian

Making it easier to find all the images in my Obsidian vault.

Some small accessibility fixes

Making the sites I work on sound a bit nicer for anyone who relies on screen readers.

Agile and iterative project management

Notes from a talk about agile and iterative approaches to project management.

Finding books in nearby library branches

Some web scraping and Python helps me find books that I can borrow immediately.

Some experiments with circle-based art

Casually covering a canvas with coloured circles.

Finding a tricky bug in Elasticsearch 8.4.2

Gradually deleting more and more data helped me get a reliable repro for an elusive bug.

My (tiny) contribution to Rust 1.64

A suggestion for a better error message to help people who work in multiple languages.

“Fixing” the rules of division

If we want to redefine how division works, Ruby is happy to oblige.

The maths cross-stitch that hangs behind me

When I’m on video calls, my backdrop has some maths-related art that I helped to make.

Generating art from lattice graphs

Randomly selecting a subset of edge from a graph can make pretty pictures.

Finding redundant data in our Next.js props

A script that helps us optimise our NEXT_DATA, which in turn helps reduce page size.

I always want StrictUndefined in Jinja

When I’m writing templates with Jinja, strict behaviour is what I want, even if it’s not the default.

An Egyptian ‘mixtape’ of embroidered material

Repeating geometric patterns make for a colourful and eye-catching piece.

Drawing a circular arc in an SVG

A Python function to help me draw circular arcs, as part of an upcoming project.

How to customise the title of Buildkite builds triggered from GitHub deployments

Getting a more descriptive build label than ‘Deployment’.

Our Place in Space

You don’t realise how big the solar system is until you’ve walked the length of it.

Cut the cutesy errors

If your app has just ruined my day, I need help, not humour.

A surprise smattering of stardom

My last post was surprisingly popular; a few reflections on the experience.

You should take more screenshots

If you do any sort of creative digital work, screenshots and screen recordings are a great way to remember it.

A Martian plaque for a made-up plot

If NASA was the first to land on Mars in For All Mankind, what would the commemorative plaque look like?

One small stitch for yarn, one giant leap for yarn-kind

I made a cross-stitch blueprint of the Apollo Moon lander and the Saturn V rocket.

Fictional phone numbers in For All Mankind

Where did this UK phone number come from?

Creating an Alfred Workflow to open GitHub repos

Automations for my automations.

Experimenting with jq as a tool for filtering JSON

I wanted to learn jq’s more powerful features, so I tried to filter some JSON from the AWS Secrets Manager CLI.

Find the dominant colours in an image in your web browser

Wrapping my CLI tool for finding dominant colours in a lightweight web app.

Running a Rust binary in Glitch

Using different targets to build Rust binaries that will run in Glitch.

Illustrating the cipher wheels of a Lorenz machine

Some old code I wrote to draw cam-accurate illustrations of cipher wheels.

Creating a “simple” three-up image layout in CSS

A step-by-step breakdown of how I made a one-left, two-right layout for my images.

Checking lots of URLs with curl

A bash script to check the HTTP status code of a bunch of URLs, for simple and portable uptime checking.

Beware delays in SQS metric delivery

A mysterious problem with SQS-based autoscaling and an over-eager CloudWatch Alarm.

A tale of two Twitter cards

Some recent changes I’ve made to fix or improve my Twitter cards.

Closing lots of Safari tabs with JXA

To help me keep my tab count down, I wrote a JXA script to close tabs that can easily be recreated.

Why is Amazon Route 53 named that way?

Digging into the history of Route 53, DNS, and port number assignments.

Creating animated GIFs from fruit and veg

Some Python code for turning MRI scans of fruit and veg into animated GIFs.

Creating coloured bookshelf graphics in Rust

Explaining some code that draws coloured rectangles in a way that looks a bit like an upside-down bookshelf.

My favourite books from 2021

Aliens and aces, railroads and racism, dating and disasters – what I enjoyed reading this year.

Why is os.sep insufficient for path operations?

Digging into a throwaway comment in the Python documentation.

The ever-improving error messages of Rust

An improvement to Rust’s error handling that I almost reported, until I realised it was fixed.

A tale of two path separators

macOS allows both the slash and colon as path separators, and this caused me no small amount of confusion.

dominant_colours, a CLI tool for finding dominant colours in an image

A new tool for playing with images.

Programatically finding the original filename of a photo in the macOS Photos Library

If you’re looking at a UUID’d file in the PhotosLibrary package, how do you find its original filename?

The Oboe of Optozorax, and Other Objects

A collection of small worldbuilding ideas about magical objects.

Prevent accidentally copying the prompt character in console code snippets

When I include console commands in a blog post, I don’t want somebody to accidentally copy the command prompt. CSS lets me avoid that.

READMEs for Open Science

Slides for a short talk about READMEs, why they’re important, and what they should contain.

Beware of incomplete PDF redactions

If you’re not careful when redacting PDFs, it’s possible to share more information than you intended.

How do you work with non-engineers?

Building a relationship founded on trust and respect.

SeptembRSE: Missing narratives in discussions around diversity and inclusion

An editing toolbar for alexwlchan.net

A bookmarklet that gives me a just-for-me toolbar to make changes to this site.

Getting a monthly cloud costs report in Slack

Sending the AWS bill to Slack, so everyone can be more informed and intentional about spending.

Operations on strings don’t always commute

Is uppercasing then reversing a string the same as reversing and then uppercasing? Of course not.

When is my EventBridge cron expression going to run next?

The AWS console will tell you when your EventBridge rule is going to run… if you know where to look.

Picking perfect planks with Python

How do you pick the right combination of planks to lay a wooden floor? Python and itertools to the rescue!

How to ignore lots of folders in Spotlight

A script that allows me to ignore folders like “target” and “node_modules”, so they don’t appear in search results.

Markdown’s gentle encouragement towards accessible images

The Markdown syntax for images reminds us that we need to write alt text.

Finding misconfigured or dangling CloudWatch Alarms

A Python script that finds CloudWatch Alarms which are based on a now non-existent source.

A few useful GitHub searches

I have hotkeys to search GitHub in several ways, including by user, by repo, and within the work organisation.

Listing deleted secrets in AWS Secrets Manager with boto3 and the AWS CLI

Diving into the internals of the AWS SDK to find deleted secrets.

Visualising how often I write in my journal

A Python script that shows me how often I’ve been journalling, so I can track my progress.

Downloading objects from/uploading files to S3 with progress bars in Python

Making it easier to see how long a file transfer will take, in the terminal.

Drawing coloured squares/text in my terminal with Python

Building Wellcome Collection’s new unified catalogue search

Collaboration between our digital and collections teams helped to build a single search box for all of our catalogues.

Using AppleScript to detect if a Safari window uses Private Browsing

Finding the app/process that’s using Secure Input

A Python script that shows me the name of processes that have Secure Input enabled.

Drawing inner/outer strokes in SVG (clips and masks)

Showing how clips and masks work, and how they can be used to draw inner and outer strokes of a shape.

Creating pairs of interlocking rainbow hearts 🌈

A web app for creating pairs of hearts based on Pride flags.

An AppleScript to toggle Voice Control

Making it slightly easier for me to enable and disable Voice Control quickly.

Wellcome’s approach to digital verification

How we ensure the safety, security and integrity of the files in Wellcome’s digital collections.

Screaming in the Cloud: Using the Cloud to Preserve the Future

I joined Corey Quinn to discuss my DynamoDB calculator and using the cloud to preserve digital collections.

How KempisBot works

How I reincarnated a fifteenth-century monk and taught him to use Twitter.

What year is it? (A tale of ISO week dates)

If you use ICU date formatting, make sure you use the right format specifier for year.

Creating short-lived, temporary roles for experimenting with AWS IAM policy documents

Create short-lived, temporary roles for experimenting with AWS IAM policy documents

“Non-technical users”

A script to copy images from Docker Hub to Amazon ECR

How I read non-fiction books

I take notes so I remember more of what I read.

Maths is about facing ambiguity, not avoiding it

School tells us that “Maths always has one right answer!”, which is a convenient but unhelpful lie.

Remembering if a <details> element was opened

A JavaScript function that remembers if a details element was reopened, and keeps it open when you reload the page.

A Python function to ignore a path with .git/info/exclude

If your Python script creates a file that you don’t want to track in Git, here’s how you can ignore it.

TIL: Using git check-ignore to debug your .gitignore

How do I use my iPhone cameras?

A script to work out which camera I use most often on my iPhone, and whether I’d miss a telephoto lens.

The danger of bad error messages

An Excel mistake shows why learning to write good error messages is a critical skill for software developers.

A new README for docstore, my tool for organising scanned paperwork

Although I don’t expect anyone to use it directly, there might be some interesting ideas that could apply elsewhere.

Replicating Wellcome Collection’s digital archive to Azure Blob Storage

How and why we keep copies of Wellcome’s digital collections in multiple cloud storage providers.

Using qlmanage to create thumbnails on macOS

How you can invoke Quick Look on the command-line to generate high-quality thumbnails.

Two Python functions for getting CloudTrail events

S3 prefixes are not directories

Although an S3 prefix looks a lot like a directory path, they aren’t the same. Whether or not you include a trailing slash can change the behaviour.

S3 keys are not file paths

Although an S3 key looks a lot like a file path, they aren’t always the same, and the distinction can trip you up.

Using fuzzy string matching to find duplicate tags

Getting a Markdown link to a window in Safari

Why do programming languages have a main() function?

Lots of programming languages have a function called main() where code starts executing. Where does this come from?

Running concurrent Try functions in Scala

If you have a function that returns Try[_], how do you call it more than once at the same time?

What does \d match in a regex?

It’s more complicated than I thought.

How to do parallel downloads with youtube-dl

Changing the accent colour of ICNS icons

Playing with macOS ICNS image files to create colourful new icons.

Using AppleScript to open a URL in Private Browsing in Safari

Fat shaming in The Good Place

How many good person points do you lose for making a joke about somebody’s weight?

Large things living in cold places

Using cold storage tiers to reduce the cost of storing Wellcome’s digital collections in the cloud.

Archive monocultures considered harmful

We are better off when the same topic is represented in multiple, different archives.

Finding the months between two dates in Python

Getting every item from a DynamoDB table with Python

A Python function that generates every item in a DynamoDB table.

Showing human-friendly dates in JavaScript

What’s a nicer way to show a date than an ISO 8601 timestamp?

The Sachsenhausen concentration camp

Feeling the weight of death in a former concentration camp.

Moving messages between SQS queues

You can send messages to a DLQ if they fail processing. What if you fix the bug, and you want to resend the failed messages?

Downloading the AO3 fics that I’ve saved in Pinboard

A script that downloads the nicely formatted AO3 downloads for everything I’ve saved in Pinboard.

Letter to my MP about Liz Truss and medical treatment for trans youth

Social media as a growth culture for opinions

Using social media can lead us to have more opinions than we really need. Can we fix that?

Taking tuple unpacking to terrible places

I want to assign a bunch of variables to True, but I don’t know how many there are. Reflection to the rescue!

Make it safe to admit mistakes

You can’t stop people making mistakes, but you can make it more likely that they’ll admit their next mistake to you.

How long is my data? 💾

A fun app to calculate the size of your data in terms of floppy disks.

Give your audience time to react

Rehearsing a presentation only tells you the minimum length of time you’ll take. If you’re speaking to a time limit, remember to leave some slack.

Illustrating lifecycle transitions in Amazon S3

A picture speaks a thousand words, which is why I always have pen and paper to hand.

Using DynamoDB as a calculator

Taking advantage of Amazon’s least-loved compute platform.

Exploring an unknown SQL server

You’re handed a SQL server which has some data, but you don’t know anything about the schema. What do you do?

Thinking about your gender

Cis people are allowed to think about their gender too.

Complex systems have complex failures

When a complex system fails, it’s usually a combination of problems, not a single person’s mistake.

Comparing JSON strings when testing in Scala

There are lots of ways to format JSON. How do you know if two JSON strings have the same data, just differently formatted?

Adventures in euphoria and embodiment

We all have bodies, and I’ve been trying to become more self-aware and connected with mine.

Access to information is a privilege

A snippet for downloading files with Python

Storing language vocabulary as a graph

Experimenting with a way to store words and phrases that highlights the connections between them.

Inclusion can’t be an afterthought

Notes from a talk about inclusion in design and unconscious bias.

Rich enough to make bad choices

If you’re rich, not only can you invest in good boots, you can also invest in experimental boot-making startups.

Sick leave while working from home

It’s okay to take sick leave if you’re working from home.

Creating striped flag wallpapers with Pillow

A Jekyll filter for adding non-breaking spaces

A way to avoid awkward line breaks in the middle of phrases.

Adjusting the dominant colour of an image

Adjusting the hue to get different colour variants of the same image.

Storing multiple, human-readable versions of BagIt bags

How we use the fetch.txt file in a bag to track multiple copies of an object in our digital archive.

Building Wellcome Collection’s new archival storage service

How we built the new cloud-based storage system for holding an ever-growing digital archive.

A deletion canary: testing your S3 bucket permissions

If you’ve tried to disable deletions in your S3 buckets, how do you know they’re working?

An interactive map of British railway stations 🚂

A map I use to plot which railway stations I’ve visited.

A Docker image to run LaTeKL^aT_eX

Generating pride-themed Norse valknuts with Python 🌈

A web app to generate mashups of Norse valknuts and Pride flags.

Finding the CPU and memory bottlenecks in an ECS cluster

This YAML file will self-destruct in five seconds!

YAML allows you to execute arbitrary code in a parser, even if you really really shouldn’t.

Some useful spreadsheet functions: FORMULATEXT, MATCH, CONCATENATE and INDIRECT

November 2019 scripts: downloading podcasts, retrying flaky errors, Azure and AWS

How I scan and organise my paperwork

My procedure for scanning paper, and organising the scanned PDFs with keyword tagging.

Saving a copy of a tweet by typing ;twurl

An AWS costs graph that works for me

How I get a Cost Explorer graph for the last 30 days of spending, broken down by service.

Digital preservation at Wellcome Collection

Slides from a presentation about our processes, practices, and tools.

Adventures in Python with concurrent.futures

Some examples of how I’ve been using concurrent.futures to speed up my batch scripting in Python.

Sans I/O programming: what, why and how (PyCon UK talk)

Code that pushes I/O to the boundary is simpler, easier to reuse and easier to test.

Adding religious holidays to my calendar

The rough edges of filecmp

The filecmp module has a confusing API, and it just caught me out.

Experiment: GitHub code search with de-duplication

Drawing with triangular coordinates in SVG

Some code and trigonometry for drawing shapes that don’t fit neatly into a rectangular grid.

Streaming large objects from S3 with ranged GET requests

Reliably reading a large object by stitching together multiple GetObject requests into a single Java InputStream.

Iterating over the entries of a compressed archive (tar.gz) in Scala

Code to turn an InputStream into an Iterator of entries from a tar.gz file or similar compressed archive in Java/Scala.

Getting a tint colour from an image with Python and k‑means

I want to display text next to an image that looks visually similar to the image, so I need to extract a tint colour.

Finding divisors of a number with Python

Using unique prime factorisations and itertools to find all the divisors of a number.

Creating preview thumbnails of PDF documents

Listing even more keys in an S3 bucket with Python

Python functions for getting a list of keys and objects in an S3 bucket.

Ten braille facts / ⠼⠁⠚⠀⠃⠗⠁⠊⠇⠇⠑⠀⠋⠁⠉⠞⠎

Where does braille come from? How was braille originally written? What can you write in braille today? And more.

An inescapable conclusion

After months of introspection and soul-searching, I’ve had some big realisations about my identity.

A Jekyll filter for obfuscating email addresses

The original Markdown implementation would do randomised hex/decimal encoding to help obscure email addresses, and I do the same in Jekyll.

Reading a Chinese dictionary / 读一本中文字典

Although paper dictionaries are mostly a thing of the past, knowing how to use a Chinese dictionary helps me learn the rest of the language.

Converting Acorn images on the command-line

I wrote some AppleScript to help me do batch conversion of Acorn images into formats like PNG and JPEG.

Hey Apple, cycle tracking isn’t just for women

At WWDC, I was disappointed to see Apple pitch period tracking exclusively towards women, and not in a more gender-inclusive way.

A script for getting cover images from mobi ebooks

Questions to ask when writing a trans inclusion policy

Notes on common themes and ideas in a variety of trans inclusion policies, as we start thinking about writing a policy at Wellcome.

Falsehoods programmers believe about Unix time

It’s not quite the number of seconds since 1 January 1970.

Creating a locking service in a Scala type class

Breaking down some tricky code that allows us to lock over concurrent operations.

Reversing a t.co URL to the original tweet

Twitter uses t.co to shorten links in tweets, so I wrote some Python to take a t.co URL and find the original tweet.

Some tips for conferences

Getting a transcript of a talk from YouTube

Using the auto-generated captions from a YouTube video as a starting point for a complete transcript.

Creating a GitHub Action to auto-merge pull requests

Saving myself the trouble of clicking that pesky “merge” button.

A day out to the Forth Bridge

Photographs from a trip to North Queensferry to see the Forth Bridge, the Forth Road Bridge, and an unexpected light tower.

Finding the latest screenshot in macOS Mojave

Atomic, cross-filesystem moves in Python

Explaining some code for moving files around in a way that’s atomic and works across filesystem boundaries.

Checking Jekyll sites with HTMLProofer

Working with really large objects in S3

Code for processing large objects in S3 without downloading the whole thing first, using file-like objects in Python.

Monki Gras 2019: The Curb Cut Effect

Slides and notes for my talk ‘The Curb Cut Effect’. Making something better for disabled people can make it better for everybody.

Notes from You Got This 2019

Notes from the inaugural ‘You Got This’ conference, a conference about creating a healthy and sustainable work life.

Notes on reading a UTF-8 encoded CSV in Python

Some notes on trying to do this in a way that supports both Python 2 and 3, and the frustration of doing so.

Iterating in fixed-size chunks in Python

A snippet for iterating over an arbitrary iterable in chunks, and returning a smaller chunk if the boundaries don’t line up.

Getting credentials for an assumed IAM Role

A script that creates temporary credentials for an assumed IAM role, and stores them in ~/.aws/credentials.

A script for backing up Tumblr posts and likes

Since Tumblr users are going on a mass deletion spree (helped by the Tumblr staff), some scripts to save content before it’s too late.

Keeping track of my book recommendations

The three lists I use to manage my book recommendations.

My visit to the Aberdulais Falls

Pictures from my trip to the waterfalls and former tin plating works at Aberdulais.

Finding SNS topics without any subscriptions

I’m trying out Go, and I wrote a tool to help me find SNS topics that don’t have any subscriptions.

Custom 404 responses in Finatra

A snippet for returning a custom 404 response in a Finatra app when somebody requests a missing page.

Assume worst intent (designing against the abusive ex)

How do we design services and platforms to reduce the risk of harassment and abuse from other users?

Building trust in an age of suspicious minds

Notes and slides from my PyCon UK 2018 keynote. In a world where people are less and less trusting, how can we take steps to make ourselves more trustable?

Signs of the time

A few lessons I learned while doing the signage for this year’s PyCon UK.

A basic error logger for Python Lambdas

A snippet to make it a bit easier to debug errors in AWS Lambda functions written in Python.

Making the venue maps for PyCon UK

A quick braindump of my thoughts from drawing some venue maps for PyCon UK.

Implementing parallel scan in DynamoDB with Scanamo

Prototype code for running a parallel scan against a DynamoDB table, and using Scanamo to serialise rows as Scala case classes.

Avoiding the automatic redirect on Tumblr posts

I see an intermittent 303 Redirect when trying to navigate to a Tumblr ‘permalink’; changing the User-Agent seems to fix it.

Ideas for inclusive conferences and events

A collection of ideas and suggestions for running conferences which are more inclusive and accessible. Based on my experiences at AlterConf, PyCon UK, and similar events.

Finding slow builds in Travis

A Python snippet for using the Travis CI API to track build times.

Moving my calendars from iCloud to FastMail

I recently discovered that iCloud was deleting my old calendar entries, so I switched to FastMail.

A robot leaked my SSH keys

A cautionary tale of a daft incident where I leaked a set of SSH keys to GitHub.

My favourite iMac accessory

Adding a USB extension cable to my iMac makes a world of difference.

Drawing ASCII bar charts

A Python snippets for drawing bar charts in command-line applications.

A brief thought on Google Duplex

I think Duplex could be a great tool for accessibility, even if that’s not what it was pitched as.

Beware of logged errors from subprocess

If you use Python’s subprocess module, be careful you don’t leak sensitive information in your error logs.

Two shortcuts for using S3 in the shell

Two shell functions for editing and inspecting S3 objects as if they were local files.

(Anti) Social Media

Slides and notes for a talk about online harassment, and why you should always design with an abusive ex in mind.

Notes on A Plumber’s Guide to Git

Git is a fundamental part of many modern developer workflows – but how does it really work under the hood? In this workshop, we’ll learn about the internals of Git.

The Hypothesis continuous release process

How we do continuous releases of hypothesis-python, and why.

Keep an overnight bag in the office

Although hopefully never needed, I think it’s worth keeping an overnight bag in your workplace.

Getting every message in an SQS queue

Code for saving every message from an SQS queue, and then saving the messages to a file, or resending them to another queue.

Listing keys in an S3 bucket with Python, redux

Python functions for getting a list of keys and objects in an S3 bucket.

IP and DNS addresses for documentation

If you’re writing technical docs and need placeholder IP addresses or DNS hostnames, there are some special values just for you!

Your repo should be easy to build, and how

Making your repo easy to clone and build is very important. This post explains why, and how I’m using Make and Docker to achieve that goal.

Pruning old Git branches

Two commands for managing Git branches: one for deleting branches which have already been merged, one for deleting branches which were deleted on a remote.

Downloading logs from Amazon CloudWatch

A detailed breakdown of how I wrote a Python script to download logs from CloudWatch.

My favourite WITCH story

As the WITCH computer celebrates five years since its reboot at TNMoC, a fun story of how it was left to run at Christmas.

Don’t tap the mic, and other tips for speakers

Tapping the microphone to test it can be bad for all sorts of reasons – and other advice from the Nine Worlds speaker guidelines.

A plumber’s guide to Git

How does Git work under the hood? How does it store information, and what’s really behind a branch?

Using privilege to improve inclusion

In the tech industry, how can we be more aware of our privilege, and use that to build inclusive cultures?

Lightning talks

Why I like the lottery system used to select lightning talks at PyCon UK this year.

Displaying tweets in Keynote

Slides for showing tweets that look like tweets on slides in Keynote and PowerPoint.

Using hooks for custom behaviour in requests

I often have code I want to run against every HTTP response (logging, error checking) — event hooks give me a nice way to do that without repetition.

Four ways to underline text in LaTeKL^aT_eX

I’m very picky about the way underlines look, and have spent a lot of time trying to get the perfect underline in LaTeKL^aT_eX.

Using pip-tools to manage my Python dependencies

How I use pip-tools to ensure my Python dependencies are pinned, precise, and as minimal as possible.

Some useful Git commands for CI

A couple of Git commands that I find useful in builds and CI.

Ode to docopt

Why I love docopt as a tool for writing clean, simple command-line interfaces.

A Python module for lazy reading of file objects

I wrote a small Python module for lazy file reading, ideal for efficient batch processing.

Backing up full-page archives from Pinboard

A Rust utility for saving local copies of my full-page archives from Pinboard.

Backing up content from SoundCloud

Listing keys in an S3 bucket with Python

A short Python function for getting a list of keys in an S3 bucket.

A visit to the Crossness pumping station

Pictures from my recent visit to Crossness, a Victorian pumping station for London’s sewers.

Accessibility at AlterConf

For accessibility and inclusion, AlterConf sets a high bar to beat.

A script for backing up your Instapaper bookmarks

A Python interface to AO3

AO3 doesn’t have an official API for scraping data - but with a bit of Python, it might not be necessary.

Experiments with AO3 and Python

AO3 doesn’t have an official API for scraping data - but with a bit of Python, it might not be necessary.

Another example of why strings are terrible

Pop quiz: if I lowercase a string, does it still have the same length as the original string?

Some low-tech ways to get more ideas

A few suggestions for “low tech devices” that aid in the process of generating ideas.

Use keyring to store your credentials

If you need to store passwords in a Python application, use the keyring module to keep them safe.

Creating low contrast wallpapers with Pillow

Take a regular tiling of the plane, apply a random colouring, and voila: a unique wallpaper, courtesy of the Python Imaging Library.

Tiling the plane with Pillow

Using the Python Imaging Library to draw regular tilings of squares, triangles and hexagons.

Why I use py.test

Why py.test is my unit test framework of choice in Python.

A shell alias for tallying data

A way to count records on the command-line.

My travelling tech bag

aspell, a command-line spell checker

Silence is golden

PyCon had a dedicated quiet room for people to get some downtime, and I think it’s a great idea.

Live captioning at conferences

Live captioning of conference talks was an unexpected bonus at this year’s PyCon UK.

Python snippets: Cleaning up empty/nearly empty directories

A pair of Python scripts I’ve been using to clean up my mess of directories.

Python snippets: Chasing redirects and URL shorteners

A quick Python function to follow a redirect to its eventual conclusion.

Clearing disk space on OS X

A few tools and utilities I’ve been using to help clear disk space on my Mac.

Reading web pages on my Kindle

A Python script I wrote that let me sends web pages from my Mac and my iPhone to my Kindle.

Introduction to property-based testing

Testing with randomly generated examples can be a good way to uncover bugs in your code.

Finding 404s and broken pages in my Apache logs

A Python script for finding 404 errors in my Apache web logs - and by extension, broken pages.

A Python smtplib wrapper for Fastmail

A quick python-smtplib wrapper for sending emails through Fastmail.

Safely deleting a file called ‘-rf *’

If for some reason you create a file called -rf *, it’s possible to delete it safely. But really, don’t create it in the first place.

Treat regular expressions as code, not magic

Regexes have a reputation for being unreadable monsters, but it doesn’t have to be that way.

Get images from the iTunes/App/Mac App Stores with Alfred

Using Alfred and a Python script to retrieve artwork from the iTunes, App and Mac App Stores.

Exclusively create a file in Python 3

If you want to create a file, but only if it doesn’t already exist, Python 3 has a helpful new file mode x.

How I use TextExpander to curb my language

I have some TextExpander snippets that I use to cut out words I don’t want to write.

The Skeletor clip loop, 2015 edition

Updating the Skeletor clip loop chart for the 2015 Clip Show.

Pretty printing JSON and XML in the shell

Backups and Docker

The Docker folder on your computer can quickly fill up space. Don’t forget to exclude it from backups.

Export a list of URLs from Safari Reading List

A Python script for getting a list of URLs from Safari Reading List.

Python and the BBC micro:bit

Playing with a tiny computer that runs Python.

Quick shell access for Docker containers

A Bash function for quickly getting shell access to Docker containers.

Review: Effective Python

A review of Effective Python, by Brett Slatkin.

Finding even more untagged posts on Tumblr

A new version of my site for finding untagged Tumblr posts.

Useful Bash features: exit traps

Persistent IPython notebooks in Windows

Configuring an IPython notebook server that is always running and easily accessible in Windows.

Safer file copying in Python

A Python script for non-destructive file copying/moving.

Useful Git features: a per-clone exclude file (.git/info/exclude)

Another way to ignore untracked files in Git.

Cloning GitHub’s Contributions chart

I made a clone of GitHub’s Contributions graph to use as a motivational tool.

Some exam advice

Some advice for students sitting technical exams

Pygmentizr

A web app for applying syntax highlighting to code using the Pygments library.

Tidying up my 1Password

Adding checkboxes to lists

A bookmarklet to add checkboxes to lists in the browser.

Kitchen sink security

Acronyms

Skeletors All the Way Down

Unpacking sets and ranges from a single string

Notes on Tumblr

Playing with 404 pages

My new standing desk

A standing desk that I built solely from IKEA parts.

Updates to my site for finding untagged Tumblr posts

A TextExpander snippet for Amazon affiliate links

A quick Alfred workflow for opening recent screenshots

Thoughts on Overcast

Some thoughts on Marco Arment’s new podcast player, Overcast.

Getting plaintext LaTeKL^aT_eX from Wolfram Alpha

Skeletor!

Finding untagged posts on Tumblr, redux

Finding untagged posts on Tumblr

Automatic Pinboard backups

A script for automatically backing up bookmarks from Pinboard

Darwin, pancakes and birthdays

Looking at whether Darwin ever missed out on birthday cake for pancakes

Zero

An essay about the number zero that I wrote for school.