Took a late hike out here for a maintenance checkup before winter: make sure the waterproof seal is good etc. Really creepy to walk out here alone in the night fog, silent except for
the occasional startling loud bellow of a rutting muntjack!
All is good here, and I was delighted to find in the logbook perhaps my favourite ever log entry in a geocache I own… it’s from the Oxfordshire County Council Countryside Access Team!
Staying at the nearby hotel I came out last night to try and find this but quickly gave up rather than poke around in the gloomy night. I’d brought a torch for exactly this kind of
purpose but accidentally left it in the car… and the car key in the hotel room!
This morning, though, was much easier. The hint object – which I hadn’t even been able to see last night! – was a great clue and I was about to find a root… I mean route… to it
through the undergrowth. TFTC!
Note for Future Dan: if you want Firefox’s picture-in-picture (popout video) mode to be available for videos of less than 45 seconds, the setting you need is media.videocontrols.picture-in-picture.video-toggle.min-video-secs. This is useful if you’ve got a playlist of multiple short clips
(which reuse the same <video> element) that you want to treat as a single long video for the purpose of picture-in-picture.
I’ve a long history of blogging about dreams I’ve had, and though I’ve not done so recently I don’t want you to think it’s because my dreams have gotten any
less trippy-as-fuck. Take last night for example…
I plough every penny and spare minute I can into a side-project that in my head at least qualifies as “art”. The result will be fake opening credits animation for the (non-existent)
pilot episode of an imagined 80s-style children’s television show. But it gets weirder.
Do you remember Hot Shots!? There’s this scene near the end where Topper Harley, played by Charlie Sheen, returns to the Native
American tribe he’s been living with since before the film (in sort of a clash between the “proud warrior
race” trope and a parody of Dances With Wolves, which came out the previous year). Returning to his teepee, Topper meets tribal
elder Owatonna (Rino Thunder), who asks him about the battle Topper had gone to fight in and, in a callback to an earlier joke, receives the four AA-cell batteries he’d asked Topper
to pick up for him “while he was out”.
There are very few occasions where a parody film is objectively better than it’s source material, but I maintain that Hot Shots! beats Top Gun hands-down.
I take the dialogue from this scene (which in reality is nonsense, only the subtitles give it any meaning),
mangle it slightly, and translate it into Japanese using an automated translation service. I find some Japanese-speaking colleagues to help verify that each line broadly makes sense,
at least in isolation.
I commission the soundtrack for my credits sequence. A bit of synth-pop about a minute long. I recruit some voice actors to read each of my Japanese lines, as if they’re characters in
an animated kids TV show. I mix it together, putting bits of Japanese dialogue in the right places so that if anybody were to sync-up my soundtrack with the correct scene in Hot
Shots!, the Japanese dialogue would closely mirror the conversation that the characters in that film were having. The scene, though, is slow-paced enough that, re-recorded, the voices
in my new soundtrack don’t sound like they’re part of the same conversation as one another. This is deliberate.
Meanwhile, I’ve had some artists put together some concept character art for me, based on some descriptions. There’s the usual eclectic mix of characters that you’d expect from 80s
cartoons: one character’s a friendly bear-like thing, another’s a cowardly robot, there’s a talking flying unicorn… you know the kind of shit. I give them descriptions, they give me
art.
Next, I send the concept art and the soundtrack to an animation team and ask them to produce a credits sequence for it, and I indicate which of the characters depicted should be
saying which lines.
Identifying the shows I lifted images from to make this sample is left as an exercise for the reader.
Finally, I dump the credits sequence around the Internet, wait a bit, and then start asking on forums “hey, what show is this?” to see what kind of response it gets.
The thing goes viral. It scratches the itch of people who love to try to find the provenance of old TV clips, but of course there’s no payoff because the show doesn’t exist. It
doesn’t take too long before somebody translates the dialogue and notices some of the unusual phasing and suggests a connection to Hot Shots! That seems to help date the show as
post-1991, but it’s still a mystery. By the time somebody get around to posting a video where the soundtrack overlays the scene from Hot Shots!, conspiracy theories are already all
over: the dominant hypothesis is that the clips are from a series of different shows (still to be identified) but only the soundtrack is new… but that still doesn’t answer what the
different shows are!
As the phenomenon begins to expand into mainstream media I become aware that even the most meme-averse folks I know are going to hear about it, at some point. And as I ‘m likely to be
“found out” as the creator of this weird thing, sooner or later, I decide to come clean about it to people I know sooner, rather than later. I’m hanging out with Ruth and her brothers Robin and Owen and I bring it up:
“Do you remember Hot Shots!? There’s this scene near the end where Topper Harley, played by Charlie Sheen…”, I begin, hoping that the explanation of my process might somehow justify
the weird shit I’ve brought to the world. Or at least, that one of this group has already come across this latest Internet trend and will interject and give me an “in”.
Ruth interrupts: “I don’t think I’ve seen Hot Shots!”
“Really?” Realising that this’ll take some background explanation, I begin by referring to Top Gun and the tropes Hot Shots! plays into and work from there.
Some time later, I’m involved with a team who are making a documentary about the whole phenomenon and my part in it. They’re proposing to release a special edition disc with a chapter
that uses DVD video’s “multi angle” and “audio format switch” features to allow you to watch your choice of either the scene from
Hot Shots! or from my trailer with your choice of either the original audio, my soundtrack, or a commentary by me, but they’re having difficulty negotiating the relevant rights.
After I woke, I tried to tell Ruth about this most-bizarre dream, but soon got stuck in an “am I still dreaming” moment after the following exchange:
It just passed two years since I started working at Automattic, and I just made a startling
discovery: I’ve now been with the company for longer than 50% of the staff.
When you hear that from a 2-year employee at a tech company, it’s easy to assume that they have a high staff turnover, but Automattic’s churn rate is relatively low, especially for our
sector: 86% of developers stay longer than 5 years. So what’s happening? Let’s visualise it:
Everything in this graph, in which each current Automattician is a square, explains how I feel right now: still sometimes like a new fish, but in an increasingly big sea.
All that “red” at the bottom of the graph? That’s recent growth. Automattic’s expanding really rapidly right now, taking on new talent at a never-before-seen speed.
Since before I joined it’s been the case that our goals have demanded an influx of new engineers at a faster rate than we’ve been able to recruit, but it looks like things are
improving. Recent refinements to our recruitment process (of which I’ve written about my experience) have helped, but I wonder how much we’ve
also been aided by pandemic-related changes to working patterns? Many people, and especially in tech fields, have now discovered that working-from-home works for them, and a company
like Automattic that’s been built for the last decade and a half on a “distributed” model is an ideal place to see that approach work at it’s best.
We’re rolling out new induction programmes to support this growth. Because I care about our corporate culture, I’ve volunteered
myself as a Culture Buddy, so I’m going to spend some of this winter helping Newmatticians integrate into our (sometimes quirky, often chaotic) ways of working. I’m quite excited to be
at a point where I’m in the “older 50%” of the organisation and so have a responsibility for supporting the “younger 50%”, even though I’m surprised that it came around so quickly.
Automattic… culture? Can’t we just show them Office Today and be done with it?
I wonder how that graph will look in another two years.
A not-entirely-theoretical question about open source software licensing came up at work the other day. I thought it was interesting
enough to warrant a quick dive into the philosophy of minification, and how it relates to copyleft open source licenses. Specifically: does distributing (only) minified
source code violate the GPL?
If you’ve come here looking for a legally-justifiable answer to that question, you’re out of luck. But what I can give you is a (fictional) story:
TheseusJS is slow
TheseusJS is a (fictional) Javascript library designed to be run in a browser. It’s released under the GPLv3 license. This license allows you to download and use TheseusJS for any purpose you like, including making money off it, modifying
it, or redistributing it to others… but it requires that if you redistribute it you have to do so under the same license and include the source code. As such, it forces you to
share with others the same freedoms you enjoy for yourself, which is highly representative of some schools of open-source thinking.
It’s a cool project, but it really needs some maintenance this side of 2010.
It’s a great library and it’s used on many websites, but its performance isn’t great. It’s become infamous for the impact it has on the speed of the websites it’s used on, and it’s
often the butt of jokes by developers: “Man, this website’s slow. Must be running Theseus!”
The original developer has moved onto his new project, Moralia, and seems uninterested in handling the growing number of requests for improvements. So I’ve decided to fork it
and make my own version, FastTheseusJS and work on improving its speed.
FastTheseusJS is fast
I do some analysis and discover the single biggest problem with TheseusJS is that the Javascript file itself is enormous. The original developer kept all of the
copious documentation in comments in the file itself, and for some reason it doesn’t even compress well. When you use TheseusJS on a website it takes a painfully long time for
a browser to download it, if it’s not precached.
Nobody even uses the documentation in the comments: there’s a website with a fully-documented API.
My first release of FastTheseusJS, then, removes virtually of the comments, replacing them with a single comment at the top pointing developers to a website where the
API is fully documented. While I’m in there anyway, I also fix a minor bug that’s been annoying me for a while.
v1.1.0 changes
Forked from TheseusJS v1.0.4
Fixed issue #1071 (running mazeSolver() without first connecting <String> component results in endless loop)
Removed all comments: improves performance considerably
I discover another interesting fact: the developer of TheseusJS used a really random mixture of tabs and spaces for indentation, sometimes in the same line! It looks…
okay if you set your editor up just right, but it’s pretty hideous otherwise. That whitespace is unnecessary anyway: the codebase is sprawling but it seldom goes more than two
levels deep, so indentation levels don’t add much readability. For my second release of FastTheseusJS, then, I remove this extraneous whitespace, as well as removing
the in-line whitespace inside parameter lists and the components of for loops. Every little helps, right?
v1.1.1 changes
Standardised whitespace usage
Removed unnecessary whitespace
Some of the simpler functions now fit onto just a single line, and it doesn’t even inconvenience me to see them this way: I know the codebase well enough by now that it’s no
disadvantage for me to edit it in this condensed format.
Personally, I’ve given up on the tabs-vs-spaces debate and now I indent my code using semicolons. (That’s clearly a joke. Don’t flame me.)
In the next version, I shorten the names of variables and functions in the code.
For some reason, the original developer used epic rambling strings for function names, like the well-known function
dedicateIslandTempleToTheImageOfAGodBeforeOrAfterMakingASacrificeWithOrWithoutDancing( boolBeforeMakingASacrifice, objectImageOfGodToDedicateIslandTempleTo,
stringNmeOfPersonMakingDedication, stringOrNullNameOfLocalIslanderDancedWith). That one gets called all the time internally and isn’t exposed via the external
API so it might as well be shortened to d=(i,j,k,l,m)=>. Now all the internal workings of the library
are each represented with just one or two letters.
v1.1.2 changes
Shortened/standarised non-API variable and function names – improves performance
I’ve shaved several kilobytes off the monstrous size of TheseusJS and I’m very proud. The original developer says nice things about my fork on social media, resulting in a
torrent of downloads and attention. Within a certain archipelago of developers, I’m slightly famous.
But did I violate the license?
But then a developer says to me: you’re violating the license of the original project because you’re not making the source code available!
This happens every day. Probably not to this same guy every time though, but you never know. Original photo by Andrea Piacquadio.
They claim that my bugfix in the first version of FastTheseusJS represents a material change to the software, and that the changes I’ve made since then are
obfuscation: efforts short of binary compilation that aim to reduce the accessibility of the source code. This fails to meet the GPL‘s definition of source code as “the preferred form of the work for making modifications to
it”. I counter that this condensed view of the source code is my “preferred” way of working with it, and moreover that my output is not the result of some build step that
makes the code harder to read, the code is just hard to read as a result of the optimisations I’ve made. In ambiguous cases, whose “preference” wins?
Did I violate the license? My gut feeling is that no, all of my changes were within the spirit and the letter of the GPL (they’re a
terrible way to write code, but that’s not what’s in question here). Because I manually condensed the code, did so with the intention that this condensing was a feature, and
continue to work directly with the code after condensing it because I prefer it that way… that feels like it’s “okay”.
But if I’d just run the code through a minification tool, my opinion changes. Suppose I’d run minify --output fasttheseus.js theseus.js and then deleted my copy of
theseus.js. Then, making changes to fasttheseus.js and redistributing it feels like a violation to me… even if the resulting code is the same as I’d have
gotten via the “manual” method!
I don’t know the answer (IANAL), but I’ll tell you this: I feel hypocritical for saying one piece of code would not violate
the license but another identical piece of code would, based only on the process the developer followed to produce it. If I replace one piece of code at a time with
less-readable versions the license remains intact, but if I replace them all at once it doesn’t? That doesn’t feel concrete nor satisfying.
Sure, I can write a blog post in just one line of code. It’ll just be a really, really, really long line… (Still perfectly readable, though!)
This isn’t an entirely contrived example
This example might seem highly contrived, and that’s because it is. But the grey area between the extremes is where the real questions are. If you agree that redistribution of (only)
minified source code violates the GPL, you’re left asking: at what point does the change occur? Code isn’t necessarily minified or
not-minified: there are many intermediate steps.
If I use a correcting linter to standardise indentation and whitespace – switching multiple spaces for the appropriate number of tabs, removing excess line breaks etc. (or do the same
tasks manually) I’m sure you’d agree that’s fine. If I have it replace whole-function if-blocks with hoisted return statements, that’s probably fine too. If I replace if blocks with
ternery operators or remove or shorten comments… that might be fine, but probably depends upon context. At some point though, some way along the process, minification goes “too
far” and feels like it’s no longer within the limitations of the license. And I can’t tell you where that point is!
This issue’s even more-complicated with some other licenses, e.g. the AGPL, which extends the requirement to share source code to hosted applications. Suppose I implement a web application that uses an AGPL-licensed library. The person who redistributed it to me only gave me the minified version, but they gave me a web address from which
to acquire the full source code, so they’re in the clear. I need to make a small patch to the library to support my service, so I edit it right into the minified version I’ve already
got. A user of my hosted application asks for a copy of the source code, so I provide it, including the edited minified library… am I violating the license for not providing the full,
unminified version, even though I’ve never even seen it? It seems absurd to say that I would be, but it could still be argued to be the case.
I love diagrams like this, which show license compatibility of different open source licenses. Adapted from a diagram by Carlo Daffara,
in turn adapted from a diagram by David E. Wheeler, used under a CC-BY-SA license.
99% of the time, though, the answer’s clear, and the ambiguities shown above shouldn’t stop anybody from choosing to open-source their work
under GPL, AGPL (or any other open source license depending on their
preference and their community). Perhaps the question of whether minification violates the letter of a copyleft license is one of those Potter Stewart “I know it when I see it” things. It certainly goes against the spirit of the thing to do so deliberately or
unnecessarily, though, and perhaps it’s that softer, more-altruistic goal we should be aiming for.
Dropped by for a maintenance visit. All is well except for a discrepancy between the paper and online logs, which I’m following up with the cachers in question.
Update: I’ve verified that everybody who’s previously logged this cache online has found the cache and held the physical logbook, even if they
haven’t signed the physical logbook.
I’ve been using Synergy for a long, long time. By the time I wrote about my
admiration of its notification icon back in 2010 I’d already been using it for some years. But this long love affair ended this week when I made the switch to its competitor,
Barrier.
I’m not certain exactly when I took this screenshot (which I shared with Kit while praising Synergy), but it’s clearly a pre-1.4 version
and those look distinctly like Windows Vista’s ugly rounded corners, so I’m thinking no later than 2009?
If you’ve not come across it before: Synergy was possibly the first multiplatform tool to provide seamless “edge-to-edge” sharing of a keyboard and mouse between multiple
computers. Right now, for example, I’m sitting in front of Cornet, a Debian 11 desktop, Idiophone, a Macbook Pro docked to a desktop monitor, and Renegade, a
Windows desktop. And I can move my mouse cursor from one, to the other, to the next, interacting with them all as if I were connected directly to it.
There have long been similar technologies. KVM switches can do this, as
can some modern wireless mice (I own at least two such mice!). But none of them are as seamless as what Synergy does: moving from computer to computer as fast as you can move your mouse
and sharing a clipboard between multiple devices. I also love that I can configure my set-up around how I work, e.g. when I undock my Macbook it switches from ethernet to wifi, this
gets detected and it’s automatically removed from the cluster. So when I pick up my laptop, it magically stops being controlled by my Windows PC’s mouse and keyboard until I dock it
again.
Synergy’s published under a hybrid model: open-source components, with paid-for extra features. It used to provide more in the open-source offering: you could download a
fully-working copy of the software and use it without limitation, losing out only on a handful of features that for many users were unnecessary. Nontheless, early on I wanted to support
the development of this tool that I used so much, and so I donated money towards funding its development. In exchange, I gained access to Synergy Premium, and then when their business
model changed I got grandfathered-in to a lifetime subscription to Synergy Pro.
I continued using Synergy all the while. When their problem-stricken 2.x branch went into beta, I was among the
testers: despite the stability issues and limitations, I loved the fact that I could have what was functionally multiple co-equal “host” computers, and – when it worked – I liked the
slick new configuration interface it sported. I’ve been following with bated breath announcements about the next generation – Synergy 3 – and I’ve registered as an alpha tester for when the time comes.
If it sounds like I’m a fanboy… that’d probably be an accurate assessment of the situation. So why, after all these years, have I jumped ship?
Dear Future Dan. If you ever need a practical example of where open-source thinking provides a better user experience than arbritrarily closed-source products, please see above.
Yours, Past Dan.
I’ve been aware of Barrier since the project started, as a fork of the last open-source version of the core Synergy program. Initially, I didn’t consider Barrier to be a
suitable alternative for me, because it lacked features I cared about that were only available in the premium version of Synergy. As time went on and these features were implemented, I
continued to stick with Synergy and didn’t bother to try out Barrier… mostly out of inertia: Synergy worked fine, and the only thing Barrier seemed to offer would be a simpler set-up
(because I wouldn’t need to insert my registration details!).
This week, though, as part of a side project, I needed to add an extra computer to my cluster. For reasons that are boring and irrelevant and so I’ll spare you the details, the new
computer’s running the 32-bit version of Debian 11.
I went to the Symless download pages and discovered… there isn’t a Debian 11 package. Ah well, I think: the Debian 10 one can probably be made to work. But then I discover… there’s only
a 64-bit version of the Debian 10 binary. I’ll note that this isn’t a fundamental limitation – there are 32-bit versions of Synergy available for Windows and for ARMhf
Raspberry Pi devices – but a decision by the developers not to support that platform. In order to protect their business model, Synergy is only available as closed-source binaries, and
that means that it’s only available for the platforms for which the developers choose to make it available.
So I thought: well, I’ll try Barrier then. Now’s as good a time as any.
Setting up Barrier in place of Synergy was pretty familiar and painless.
Barrier and Synergy aren’t cross-compatible, so first I had to disable Synergy on each machine in my cluster. Then I installed Barrier. Like most popular open-source software, this was
trivially easy compared to Synergy: I just used an appropriate package manager by running choco install barrier, brew install barrier, and apt install barrier to install on each of the Windows, Mac, and Debian computers, respectively.
Configuring Barrier was basically identical to configuring Synergy: set up the machine names, nominate one the server, and tell the server what the relative positions are of each of the
others’ screens. I usually bind the “scroll lock” key to the “lock my cursor to the current screen” function but I wasn’t permitted to do this in Barrier for some reason, so I remapped
my scroll lock key to some random high unicode character and bound that instead.
Getting Barrier to auto-run on MacOS was a little bit of a drag – in the end I had to use Automator to set up a shortcut that ran it and loaded the configuration, and set that to run on
login. These little touches are mostly solved in Synergy, but given its technical audience I don’t imagine that anybody is hugely inconvenienced by them. Nonetheless, Synergy clearly
retains a slightly more-polished experience.
Altogether, switching from Synergy to Barrier took me under 15 minutes and has so far offered me a functionally-identical experience, except that it works on more devices, can be
installed via my favourite package managers, and doesn’t ask me for registration details before it functions. Synergy 3’s going to have to be a big leap forward to beat that!
Called @Tesco Abingdon for a #flujab but fell down a black hole in their menu system. Had to choose the “continue to hold” option several times… and then nobody answered
anyway…
For most of 2013/2014 and intermittently thereafter my sister ran a weekly-ish “Family Vlog” on YouTube, and I (even more-intermittently) did an ocasional
tonge-in-cheek review and analysis of them.
Today, a friend reported that they had eaten “Sunday dinner on a Wednesday”, and I found myself reminded of a running gag in this old, old vlog… and threw together a quick compilation
reel of some of its instances.
Today is “superhero day” for nursery/reception, so I continued my effort to straddle the line between being a fun #parent and an embarassing parent line by dropping the kids off like
this:
I like to check in on my new caches after about a week in the field to ensure there are no teething troubles with their hiding place/weatherproofing etc. All looks good here!
As you might know if you were paying close attention in Summer 2019, I run a “URL
shortener” for my personal use. You may be familiar with public URL shorteners like TinyURL
and Bit.ly: my personal URL shortener is basically the same thing, except that only
I am able to make short-links with it. Compared to public ones, this means I’ve got a larger corpus of especially-short (e.g. 2/3 letter) codes available for my personal use. It also
means that I’m not dependent on the goodwill of a free siloed service and I can add exactly the features I want to it.
Little wonder then that my link shortener sat so close to me on my ecosystem diagram the other year.
For the last nine years my link shortener has been S.2, a tool I threw together in Ruby. It stores URLs in a
sequentially-numbered database table and then uses the Base62-encoding of the primary key as the “code” part of the short URL. Aside from the fact that when I create a short link it shows me a QR code to I can
easily “push” a page to my phone, it doesn’t really have any “special” features. It replaced S.1, from which it primarily differed by putting the code at the end of the URL rather than as part of the domain name, e.g. s.danq.me/a0 rather than a0.s.danq.me: I made the switch
because S.1 made HTTPS a real pain as well as only supporting Base36 (owing to the case-insensitivity of domain names).
But S.2’s gotten a little long in the tooth and as I’ve gotten busier/lazier, I’ve leant into using or adapting open source tools more-often than writing my own from scratch. So this
week I switched my URL shortener from S.2 to YOURLS.
YOURLs isn’t the prettiest tool in the world, but then it doesn’t have to be: only I ever see the interface pictured above!
One of the things that attracted to me to YOURLS was that it had a ready-to-go Docker image. I’m not the biggest fan of Docker in general,
but I do love the convenience of being able to deploy applications super-quickly to my household NAS. This makes installing and maintaining my personal URL shortener much easier than it
used to be (and it was pretty easy before!).
Another thing I liked about YOURLS is that it, like S.2, uses Base62 encoding. This meant that migrating my links from S.2 into YOURLS could be done with a simple cross-database
INSERT... SELECT statement:
One of S.1/S.2’s features was that it exposed an RSS feed at a secret URL for my reader to ingest. This was great, because it meant I could “push” something to my RSS reader to read or repost to my blog later. YOURLS doesn’t have such a feature, and I couldn’t find anything in the (extensive) list of plugins that would do it for me. I needed to write my own.
In some ways, subscribing “to yourself” is a strange thing to do. In other ways… shut up, I’ll do what I like.
I could have written a YOURLS plugin. Or I could have written a stack of code in Ruby, PHP, Javascript or
some other language to bridge these systems. But as I switched over my shortlink subdomain s.danq.me to its new home at danq.link, another idea came to me. I
have direct database access to YOURLS (and the table schema is super simple) and the command-line MariaDB client can output XML… could I simply write an XML
Transformation to convert database output directly into a valid RSS feed? Let’s give it a go!
I wrote a script like this and put it in my crontab:
mysql --xml yourls -e \"SELECT keyword, url, title, DATE_FORMAT(timestamp, '%a, %d %b %Y %T') AS pubdate FROM yourls_url ORDER BY timestamp DESC LIMIT 30"\
| xsltproc template.xslt - \
| xmllint --format - \
> output.rss.xml
The first part of that command connects to the yourls database, sets the output format to XML, and executes an
SQL statement to extract the most-recent 30 shortlinks. The DATE_FORMAT function is used to mould the datetime into
something approximating the RFC-822 standard for datetimes as required by
RSS. The output produced looks something like this:
<?xml version="1.0"?><resultsetstatement="SELECT keyword, url, title, timestamp FROM yourls_url ORDER BY timestamp DESC LIMIT 30"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><row><fieldname="keyword">VV</field><fieldname="url">https://webdevbev.co.uk/blog/06-2021/perfect-is-the-enemy-of-good.html</field><fieldname="title"> Perfect is the enemy of good || Web Dev Bev</field><fieldname="timestamp">2021-09-26 17:38:32</field></row><row><fieldname="keyword">VU</field><fieldname="url">https://webdevlaw.uk/2021/01/30/why-generation-x-will-save-the-web/</field><fieldname="title">Why Generation X will save the web Hi, Im Heather Burns</field><fieldname="timestamp">2021-09-26 17:38:26</field></row><!-- ... etc. ... --></resultset>
We don’t see this, though. It’s piped directly into the second part of the command, which uses xsltproc to apply an XSLT to it. I was concerned that my XSLT
experience would be super rusty as I haven’t actually written any since working for my former employer SmartData back in around 2005! Back then, my coworker Alex and I spent many hours doing XML
backflips to implement a system that converted complex data outputs into PDF files via an XSL-FO intermediary.
I needn’t have worried, though. Firstly: it turns out I remember a lot more than I thought from that project a decade and a half ago! But secondly, this conversion from MySQL/MariaDB
XML output to RSS turned out to be pretty painless. Here’s the
template.xslt I ended up making:
<?xml version="1.0"?><xsl:stylesheetxmlns:xsl="http://www.w3.org/1999/XSL/Transform"version="1.0"><xsl:templatematch="resultset"><rssversion="2.0"xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>Dan's Short Links</title><description>Links shortened by Dan using danq.link</description><link> [ MY RSS FEED URL ]</link><atom:linkhref=" [ MY RSS FEED URL ] "rel="self"type="application/rss+xml"/><lastBuildDate><xsl:value-ofselect="row/field[@name='pubdate']"/> UTC</lastBuildDate><pubDate><xsl:value-ofselect="row/field[@name='pubdate']"/> UTC</pubDate><ttl>1800</ttl><xsl:for-eachselect="row"><item><title><xsl:value-ofselect="field[@name='title']"/></title><link><xsl:value-ofselect="field[@name='url']"/></link><guid>https://danq.link/<xsl:value-ofselect="field[@name='keyword']"/></guid><pubDate><xsl:value-ofselect="field[@name='pubdate']"/> UTC</pubDate></item></xsl:for-each></channel></rss></xsl:template></xsl:stylesheet>
That uses the first (i.e. most-recent) shortlink’s timestamp as the feed’s pubDate, which makes sense: unless you’re going back and modifying links there’s no more-recent
changes than the creation date of the most-recent shortlink. Then it loops through the returned rows and creates an <item> for each; simple!
The final step in my command runs the output through xmllint to prettify it. That’s not strictly necessary, but it was useful while debugging and as the whole command takes
milliseconds to run once every quarter hour or so I’m not concerned about the overhead. Using these native binaries (plus a little configuration), chained together with pipes, had
already resulted in way faster performance (with less code) than if I’d implemented something using a scripting language, and the result is a reasonably elegant “scratch your
own itch”-type solution to the only outstanding barrier that was keeping me on S.2.
All that remained for me to do was set up a symlink so that the resulting output.rss.xml was accessible, over the web, to my RSS reader. I hope that next time I’m tempted to write a script to solve a problem like this I’ll remember that sometimes a chain of piped *nix
utilities can provide me a slicker, cleaner, and faster solution.
Update: Right as I finished writing this blog post I discovered that somebody had already solved this
problem using PHP code added to YOURLS; it’s just not packaged as a plugin so I didn’t see it earlier! Whether or not I
use this alternate approach or stick to what I’ve got, the process of implementing this YOURLS-database ➡ XML
➡ XSLT ➡ RSS chain was fun and
informative.
