If you want to see how long your database queries actually take, you need to disable MySQL's query cache. This can be done globally by logging into a database console, run

SET GLOBAL query_cache_type=OFF;

and restart your rails server.

You can also disable the cache on a per query basis by saying

SELECT SQL_NO_CACHE * FROM ...

You also probably want to disable Rails internal (per-request) cache. For this, wrap your code with a call to ActiveRecord::Base.uncached. For example, as an around_filter:

d...

We want to keep a changelog for all gems we maintain. There are some good practices for writing a changelog that adds value, please stick to these.

• Add a notice to the README's contribute section about the changelog
• For every release update the changelog
• Note the date format yyyy-mm-tt

What is a changelog?

A changelog is a file which contains a curated, chronologically ordered list of notable changes for each version of a project.

Why keep a changelog?

To make it easier for users and...

1. Class-level process definitions are only applied to the original file
2. Versions are generated based on the processed original file
3. Callbacks (before/after) are applied to original file and each version by itself
4. Under the hood, a version is an instance of the uploader class that has no versions
5. Version uploader and original uploader can be distinguished by checking #version_name: version uploaders return the version name, whereas the original uploader instance returns nil
6. Version instances do not have a re...

If you want to system-wide disable the microphone of your external webcam in PulseAudio use the following one-liners:

# Connected cards
$ pactl list short cards
1       alsa_card.pci-0000_00_1f.3      module-alsa-card.c
5       alsa_card.usb-Lenovo_ThinkPad_Thunderbolt_4_Dock_USB_Audio_000000000000-00      module-alsa-card.c
6       alsa_card.usb-HD_Webcam_C270_HD_Webcam_C270-02  module-alsa-card.c

# Disable  HD_Webcam_C27
$ pactl list short cards | grep HD_Webcam_C27 | cut -f2 | xargs -rt -I % pactl set-card-profile % off
pactl s...

The author describes his little journey in hunting down a memory leak. Maybe his approach and tooling may one day help you in a similar situation.

Tools: rbtrace, ObjectSpace.trace_object_allocations_start, heapy, sheap

10.0.0 2024-03-07

Compatible changes

• console command: You can now globally disable the IRB multiline feature by setting irb_flags: --nomultiline in ~/.config/geordi/global.yml. All configured irb_flags are automatically passed on to the console IRB.
• console command: Ctrl + C now properly exits a local Rails console
• rspec and cucumber commands: Run specs even if the automatic chromedriver update fails
• Improve detection of IRB version
• Add new hints to 'Did you know'

Breaking changes

• dump command: Drop...

Rachel Andrew has built a website about CSS Grid.

• Video tutorials
• More than 30 layout examples for feature demonstration
• Layout patterns for copy-paste use
• All grouped by topic: "Placing items onto the grid", "Sizing of tracks and items" etc. with video, linked articles, examples each

You can chain multiple Capybara matchers on the page or any element:

expect(page)
  .to have_content('Example Course')
  .and have_css('.course.active')
  .and have_button('Start')

When you chain multiple matchers using and, [Capybara will retry the entire chain](https://github.com/teamcapybara/capybara/blob/c0cbf4024c1abd48b0c22c2930e7b05af58ab284/lib/capybara/rspec/matc...

A list of implementation details that make for a better / expected user experience. Have these in mind when implementing a web design.

This document outlines a non-exhaustive list of details that make a good (web) interface. It is a living document, periodically updated based on learnings. Some of these may be subjective, but most apply to all websites. The WAI-ARIA spec is deliberately not duplicated in this document. However, some accessibility guidelines may be pointed out.

The CSS property z-index is not as global as you might think. Actually, it is scoped to a so-called "stacking context". z-indexes only have meaning within their stacking context, while stacking contexts are treated as a single unit in their parent stacking context. This means indices like 99999 should never actually be needed.

Creating a new stacking context

In order to create a stacking context with the least possible side effects, use the isolation property on an...

Trick: Do not use convert but mogrify:

mogrify -resize 50% *

This overwrites the original image file.

In contrast, convert writes to a different image file. Here is an example if you need this:

cd /path/to/image/directory
for i in `ls -1 *jpg`; do convert -resize 50% $i "thumb_$i"; done

A common cause of non-accessible web pages are elements that were made interactive via JavaScript but cannot be focused or activated with anything but the mouse.

❌ Bad example

Let's take a look at a common example:

<form filter>
  <input filter--query name="query" type="text">
  <span filter--reset>Clear Search</span>
</form>

The HTML above is being activated with an Unpoly compiler like this:

up.compiler('[filter]', function(filterForm) {
  const resetButton = filterForm.querySelec...

These are the top ten accessibility errors as researched by TPGi, a company focusing on accessibility. See the linked article for details on each item, as well as instructions on how to do it correctly.

1. No link text
2. Non-active element in tab order
3. Missing link alt attribute
4. No alt text
5. List not nested correctly
6. Duplicate labels used
7. Positive tabindex value
8. Invalid aria-describedby
9. No label for button element
10. Invalid aria-labelledby

Generally, I am surprised by these items. I would have expected more complex i...

I recently built a screen with a very high and wide table in the center. This posed some challenges:

• Giving the table a horizontal scroll bar is very unergonomic, since the scrollbar might be far off screen.
• Making the whole page scrollable looks bad, since I don't want the rest of the UI to scroll.
• Giving the table its own vertical scrollbar and a limited height would have solved it, but felt weird, since the table was 90% of the page.

What I ended up doing is reusing the horizontal page scrollbar (which is naturally fixed at t...

JavaScript objects can have getter and setter functions that are called when a property is read from or written to.

For example, if you'd like an object that has a virtual person.fullName attribute that dynamically composes person.firstName and person.lastName:

var person = {

  firstName: 'Guybrush',

  lastName: 'Threepwood',

  get fullName() {
    return this.firstName + " " + this.lastName;
  },
  
  set fullName(name) {
    var parts = name.split(" ");
    this.firstName = parts[0];
    this.lastName = parts[1];
  }

};
`...

Custom matchers are a useful RSpec feature which you can use to DRY up repetitive expectations in your specs. Unfortunately the default directory structure generated by rspec-rails has no obvious place to put custom matchers or other support code.

I recommend storing them like this:

spec/support/database_cleaner.rb
spec/support/devise.rb
spec/support/factory_bot.rb
spec/support/vcr.rb
spec/support/matchers/be_allowed_access.rb
s...

Knowing when to refactor

Just feeling like refactoring is not a good reason to do it. Make an educated decision: Is the code change worth the effort? Stay straight on track, don't go astray.
Note: Usually, you'd refactor after finishing your story. At times, it might be necessary to refactor up front. But try to keep refactoring out of your current task.

Knowing where to optimize

Things should only be optimized a) when they have settled, i.e. haven't changed for a longer time, and b) when there is a measurable gain from th...

It is good programming practice to Don't Repeat Yourself (or DRY). In Ruby on Rails we keep our code DRY by sharing behavior by using inheritance, modules, traits or partials.

When you reuse behavior you want to reuse tests as well. You are probably already reusing examples in unit tests. Unfortunately it is much harder to reuse code when writing integration tests with Cucumber, where you need to...

When you are using lambdas in RSpec to assert certain changes of a call, you know this syntax:

expect { playlist.destroy }.to change { Playlist.count }.by(-1)

While you can define multiple assertions through multiple specs, you may not want to do so, e.g. for performance or for the sake of mental overhead.

Multiple expectations on the same subject

RSpec allows chaining expectations simply by using and.

expect { playlist.destroy }
  .to change { Playlist.count }.by(-1)
  .and not_change { Video.count }

...

By default, Rails' validates_uniqueness_of does not consider "username" and "USERNAME" to be a collision. If you use MySQL this will lead to issues, since string comparisons are case-insensitive in MySQL.

(If you use PostgreSQL, read this instead.)

Say you have a user model

class User < ActiveRecord::Base
  validates_uniqueness_of :name
end

with a unique index in the database.

If you try to create the users "user" and "USER", this will not trigger a validation error, but may fail with an SQL error due ...

General

A general overview about why and how we migrate can be found under Migrating from Elasticsearch to Opensearch

This card deals with specifics concerning the use of searchkick.

Step 1: Make Opensearch available for Searchkick

In your Gemfile

# Search
gem 'searchkick'                   # needs to be > 5, to use Opensearch 2
gem 'elasticsearch'
gem 'opensearch-ruby'

in config/initializers/searchkick.rb (or wherever you have configured your Searchkick settings) add:

SEARCHKICK_CLIENT_T...

The Web Animations API has great browser support, and you should be using it to animate DOM elements from JavaScript, or to control or wait for CSS animations.

Here is a quick overview of a few useful features:

Animating elements from JavaScript

Use the Element#animate() function to perform animations on an element.

Its API probably a bit different from how your...

Today I stumbled across a pretty harmless-looking query in our application which turned out to be pretty harmful and caused huge memory usage as well as downing our passenger workers by letting requests take up to 60 seconds. We had a method that received a scope and then checked, if the scope parameter was blank? and aborted the method execution in this case.

def foo(scope)
  return if scope.blank?
  
  # Use scope, e.g.
  scope.find(...)
end

We then called this method with an all scope: foo(Media::Document::Base.all). *...