When to use decorators

An article, posted 24 days ago filed in ruby, rails, ruby on rails, service, architecture, when to use & models.

Are you sure?

Decorators decorate your class with new set of functionality.

What are your decorators doing? Adding a few rendering specific methods to a class to help with rendering? Perhaps you should consider Presenters. But better: how will it scale, can it be grouped, will it really add the simplification. Be wary of too quick branching off functionality to decorators. Most cases I've seen them were overly architectured, and they didn't bring much value.

One might consider using Concerns or mixins as an alternative. The disadvantage here is that your main object gets more public methods, but I consider it as a feature after having experienced too much potentially reusable functionality grouped arbitrarily away in other presenter / decorator classes.

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I love you ruby, `unless`...

An article, posted 27 days ago filed in sorting, ruby & programming.

I'm quite familiar with writing ruby code. I've even expressed my love for the language long time ago. But some constructs still bug me. One of them is unless…

I've seen variants of this code:

temperature = 36.7
unless temperature > 37.2 || temperature  35.5 && temperature < 37.2
  puts "Healthy temperature. Temperature is within the normal range."

or perhaps even nicer:

if (35.5...37.2).include?
  puts "Healthy temperature. Temperature is within the normal range."

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Data recovery adventures

An article, posted 28 days ago filed in harddrive, recovery, hdd, files, data & backup.

I'm not a data recovery specialist, but I tend to help people out every now and then with computer problems, and sometimes you have to deal with a disk that doesn't seem to work anymore. This is a collection of notes I made after I got a new challenge. I had to resort to using testdisk and ddrescue. I've been testing a few tools, and read about more, but these were the tools I landed on.

IMPORTANT: I'm not an expert on this topic. Every additional moving of the needle can cause a harddrive to fail even harder. If your data is absolutely critical, use a certified data recovery service.

1. Is it replaceable hardware?

When I get a harddrive in a laptop or external enclosure, my first attempt is to see if there is something between computer and the disk. I try to remove the disk from the computer or enclosure and connect it to a USB3 to 4-types of P/SATA adapter I have bought years ago and has saved me multiple times. If it mounts, copy everything to another drive, to b…

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Terugblik op PublicSpaces Conferentie 2024

An article, posted about one month ago filed in microsoft, google, kimvsparrentak, europa, public, cloud, azure, AWS, amazon, eu & ibm.

Veel inspirerende en mooie woorden dit jaar op PublicSpaces Conferentie 2024, maar vrij van zorgen was ik erna niet. Op de tweede dag sprak Bert Hubert uit in een jolig pessimistisch verhaal dat hij er vanuit gaat dat over enkele jaren 98% van de e-mails verzonden wordt vanuit dan wel servers van Microsoft dan wel Google. Ik hoopte na de PublicSpaces conferentie terug te gaan met nieuwe moed en handgrepen een kleine bijdrage te kunnen leveren om deze beweging te kenteren, maar desillusie is het gevoel dat me beklijft. Misschien moeten we hoop hebben dat de uit de DMA act volgende aanscherping van de aanbestedingsregels helpt om te voorkomen dat de grote partijen niet alles op kunnen slikken, zoals Kim van Sparrentak (MEP voor GroenLinks, voor wie ik eerder een positief stemadvies gaf) aangaf. Maar terwijl [Amsterdam trots aankondigt bezit te zijn met een "autonome strategie"](https://a…

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Should I be upgrading all my dependencies on a regular basis?

An article, posted about 2 months ago filed in engineering, software, google, security, gems, programming & development.

For projects I maintain, I try to keep dependencies up to date on a regular basis. But not all people work like that, some live by the adage of "if it ain't broken don't fix it", but that is not an approach I subscribe to in software development.

A common reason to update software dependencies is to fix security issues or bug fixes that plague the project at hand. My main argument in favour of making more frequent updates is that when you suddenly need to make an update (because of an imminent security threat) it won't be hard; when dependencies haven't been updated in a long time it can be hard to to make the update.

There are risks involved in updating dependencies: A new version might introduce breaking changes, things that you rely on suddenly don't work or exist anymore. It might even introduce new bugs that may not be apparent on the first run. And when your test suite is not on par, verifying if everything works as expected is time consuming. But that can all be address…

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Sorting text

An article, posted 2 months ago filed in sorting, ruby, programming, database, order, databases & sql.

There are a few hard problems in computing. Correctly handling time, naming, preventing off by one errors… sorting text may not be one of them but recently we ran into a discussion where I couldn't make up my mind anymore. Hence, this post's topic: sorting text.

The problem

How do you sort the following words:

  • cheese
  • Ape
  • Drums
  • dent
  • Beer

If you'd ask ruby I'd get:

 %w[cheese Ape Drums dent Beer].sort

Results in:

  1. Ape
  2. Beer
  3. Drums
  4. cheese
  5. dent

Which in my useless and ramshackle programmer's brain translates to, well why not, it is sorted right?

But then we moved the data into a database which was correctly set up with a proper locale for 'collation', a term that I've seen but never meant anything to me until this problem. Collation is:

> the assembly of written information into a standard order.

(thanks Wikipedia - Collation)


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Recommended Dutch beers

An article, posted 3 months ago filed in recommendation, local & amsterdam.

I was asked to make a list of my favourite beers…

For regular drinking, it is never a bad idea to go into a supermarket and to take a box of Gulpener Biologisch (organic). Gulpener harvests all their ingredients close to the brewery. They have three variants, a regular Pilsner, a Weizen and an IPA. Recently I drank their organic Pilsner again after choosing mostly their IPA variant, and realised that it is close to defining Pilsner. Their IPA is also never disappointing, and one that stands above many of these cooler smaller fancy (read more expensive) IPA’s.

Then what other beers? Amsterdam itself has lots of smaller breweries, biggest of the smallest is Brouwerij ’t IJ. Try Columbus for a heavier one (9%; IJ is the name of the river through amsterdam, which is in pronounciation not different from Dutch ‘ei’, which translates to egg, hence all kinds of twists around egg, egg of columbus etc. [Troost](https://bro…

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Blog concept: Sketchy optimisations

An article, posted 4 months ago filed in activerecord, database, optimization, orm, performance, query, rails, software & sql.

Recently a colleague was showing me a concept he was working on. He drafted a change in a fight against so-called 1+n-queries (actually for some reason unknown to me they're called n+1 queries, but my head isn't able to process the problem with just one more query after n queries…); in software development using ORMs like active record it is quite easy to make a single database request objects that when a presented within a view trigger other queries for every object because it has a relationship. Round trips to databases are generally bad as they take time.

For his change, he introduced a new class that we could seemingly reuse, with a just another (a bad code-smell) declaration of relations between objects and whether these should be preloaded when retrieving the primary object. This was in response to indeed a quite bad part of our code that entailed returning objects with counts of selected associations, but instead of counting these in the database, the current code was a…

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The Mega apps

An article, posted 5 months ago filed in app, apple, eclipse, Evolution, java, linux, netscape, os, OSS, outlook, uml, Firefox, ai & mozilla.

Around 2000 I worked on Java Web apps using Eclipse, an open source IDE, which was also extendable with all kinds of tools. Since it was an IDE some made tools for drawing code with UML (connecting named boxes with attributes). But it was also the playground for tools less related to coding. It became a kind of OS running on an OS.

Less niche, was perhaps Netscape Communicator. It was a web browser, an email client, a webpage builder, a calendar … all in one. And also quite extendible again with plugins. The idea still lives on in the Mozilla Seamonkey-project.

A remnant of this is perhaps Microsoft Outlook. An e-mail client with integrated calendar app. An approach mimicked by Evolution on Linux.

I was reminded by all this [because Mozilla wants to focus on integrating AI in their flagship product Firefox](https://arstechnica.com/gadgets/2024/02/mozilla-lay…

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When to use x-objects?

An article, posted 7 months ago filed in ruby, rails, ruby on rails, service, architecture & when to use.

So I wrote a few short articles on when to use FormObjects and Jobs and ServiceObjects. The question is of course "it depends", but the leading principle I have is keep it simple. That being said, for inspiration, some suggestion for different layers to manage the application complexity from Vladimir Dementyev's talk on Railsconf:


  • Controllers (standard Rails)
  • Channels (standard Rails)
  • Views (standard Rails)
  • Presenters
  • Form Objects
  • Filter Objects


  • Authorization Policies
  • Jobs (standard Rails)
  • Event listeners
  • Interactors
  • Deliveries
  • Notifiers
  • Mailers (s…

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When to use Modules / Concerns?

An article, posted 9 months ago filed in ruby, rails, ruby on rails, service, architecture, when to use & modules.

Whenever your model gets too heavy?

The easiest way to clean up your classes might be to create smaller, more concise methods. The next easiest way of tiding up your models is moving stuff to modules (whether they are 'Concerns' or not). Modules can then be included in the final classes. It will lead to a crowded list of methods exposed on these classes, for which alternative solutions exist (Presenters, Decorators), but if you shield off private methods nicely and have a consistent way of naming things, I wouldn't be too concerned about that. Note that having many modules used in only a single class might be a code smell: perhaps you're trying to do too much with that single class.

Concerns or Modules?

When you're using Rails, you can make use of Concerns. They offer a few advantages over traditional modules, so use it whenever you're bothering recreating the same behaviour using plain old ruby Modules. I prefer consistency, so if you've adopted Concerns, use con…

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When to use Form-objects?

An article, posted 9 months ago filed in ruby, rails, ruby on rails, service, architecture, when to use, async, form & models.

When necessary.

It depends. By default I would advise against them; not creating Form objects to receive and validate data that could be validated by the Model directly. Even when you have a few nested attributes that belong to the main model modified, I would advise against Form objects. Keep It Simple.

But… sometimes you have more complex forms that don't fit the database-mirroring ActiveRecord model as nicely.

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When to use Job (or Worker) objects?

An article, posted 9 months ago filed in ruby, rails, ruby on rails, service, architecture, when to use & async.


When you are able to do stuff async (not blocking the web-request), make it async. It will also reduce the need for a category of Service-objects. Worker or Job objects can often be called inline if desired.

Sidenote: I personally prefer the "Job" object name, a Job that needs to be performed. Worker is a name that was popularised by Sidekiq, but Sidekiq moved to Jobs as well.

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Tag descriptor

When to use...

An article, posted 9 months ago filed in ruby.

I've got some opinions about certain ways of setting up more advanced (mostly Rails) applications. These might be short 'posts' which I might return to later. Let's see how it goes :)

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When to use Service-objects?

An article, posted 9 months ago filed in ruby, rails, ruby on rails, service, architecture & when to use.


There is of course never an absolute answer to stuff but if you are running it in a background job anyway have you considered directly writing it in a Worker or Job-object? Note that you can always run jobs async when needed.

My main objection against service objects is that all too often they are ill defined as a category. So while having fat controllers or fat models may be a bad thing, just creating a bunch of somewhat arbitrary 'Services' is not making the code more manageable.

When considering adding a 'services' directory to your app, try to think of what class of problems you want to tackle. And when in doubt, just keep messing around with the somewhat fatter models & controllers.

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