Sometimes you have a file that is related to a project, while not actually being part of it. You'd like to keep them around, but others won't need them – e.g. some notes, a log, or a database dump.

Sure, you have a project directory – but all of it is tracked by Git. A project's tmp/ directory is usually not tracked, but by definition it is not a good place to keep things.

An excluded directory for related files

I suggest you keep your related files in a related-files/ directory within your project(s).

To keep this directory u...

The linked table shows the support lifecycle for Firefox Extended Support Releases (ESR) which we sometimes need to support for enterprise customers.

The ESR cadence works something like this:

• Firefox ESR freezes the then-current Firefox version for a year.
• During this year Mozilla backports security patches to the current ESR, but does not add features.
• Two subsequent ESR releases overlap for three months. This way enterprises have a quarter to test the new version and migrate their clients.

tl;dr

We recommend configuring Selenium's unhandled prompt behavior to "ignore".

When running tests in a real browser, we use Selenium. Each browser is controlled by a specific driver, e.g. Selenium::WebDriver::Chrome for Chrome.

There is one quirk to all drivers (at least those following the W3C webdriver spec) that can be impractical:
When any user prompt (like an alert) is encountered when trying to perform an action, they will [dismiss the dialog by default](https://w3c....

You want to use <input type="number"> fields in your applications.
However, your desktop users may encounter some weird quirks:

1. Aside from allowing only digits and decimal separators, an "e" is also allowed (to allow scientific notation like "1e3").
   • Non-technical users will be confused by this.
   • Your server needs to understand that syntax. If it converts only digits (e.g. to_i in Ruby) you'll end up with wrong values (like 1 instead o...

Rails includes a way to see what an e-mail will look like.

Integration to RSpec

All you need to do is implement a preview-class in spec/mailers/previews/notifier_preview.rb:

class NotifierPreview < ActionMailer::Preview
  def welcome
    Notifier.welcome(User.first)
  end
end

And adapt the preview load path in your application.rb:

config.action_mailer.preview_path = "#{Rails.root}/spec/mailers/previews" # this is already set as default by Rails

Then a preview will be available in the browser at `http://lo...

Find-as-you-type boxes are usually built by observing changes in a text field, and querying the server via AJAX for search results or suggestions when the field has changed.

A common problem with this implementation is that there is no guarantee that AJAX responses are evaluated in the same order as the original requests. The effect for the user is that the search results are flashing back and forth while the user is typing the query, and when the user has stopped typing the last results don't always match the final query.

Workarounds
----...

To show your key inputs on screen, e.g. for a screencast or screen sharing, you can use screenkey.

A really useful flag is --show-settings. Running screenkey --show-settings shows a settings window, which allows you to easily adjust the key overlay.
The option Select window/region is especially useful for choosing where the overlay is placed.

A Rails script lives in lib/scripts and is run with bin/rails runner lib/scripts/.... They are a simple tool to perform some one-time actions on your Rails application. A Rails script has a few advantages over pasting some prepared code into a Rails console:

• Version control
• Part of the repository, so you can build on previous scripts for a similar task
• You can have tests (see below)

Although not part of the application, your script is code and should adhere to the common quality standards (e.g. no spaghetti code). However, a script...

When testing JavaScript functionality in Selenium (E2E), you may need to access a class or function inside of a evaluate_script block in one of your steps. Capybara may only access definitions that are attached to the browser (over the window object that acts as the base). That means that once you are exporting your definition(s) in Webpacker, these won't be available in your tests (and neither in the dev console). The following principles/concepts also apply to Sprockets.

Say we have a StreetMap class:

// street_map.js
class S...

git --fixup is very handy to amend a change to a previous commit. You can then autosquash your commits with git rebase -i --autosquash and git will do the magic for you and bring them in the right order. However, as git --fixup wants a ref to another commit, it is quite annoying to use since you always have to look up the sha of the commit you want to amend first.

Inspired by the [shortcut to checkout recent branches with fzf](https://makandracards.com/makandra/505126-g...

When doing some meta-programming magic and you want to do something for all attributes of a class, you may need to access connection or some of its methods (e.g. columns) during class definition.

While everything will be fine while you are working on a project that is in active development, the application will fail to boot when the database is missing or has no tables. This means that Raketasks like db:create or db:migrate fail on a freshly cloned project.

The reason is your environment.rb which is loaded for Raketasks and calls...

Example

87.140.79.42 - - [23/Jan/2024:09:00:46 +0100] "GET /monitoring/pings/ HTTP/1.1" 200 814 "-" "Ruby"
87.140.79.42 - - [23/Jan/2024:09:00:46 +0100] "GET /monitoring/pings/ HTTP/1.1" 200 814 "-" "Ruby"
87.140.79.41 - - [23/Jan/2024:09:00:46 +0100] "GET /monitoring/pings/ HTTP/1.1" 200 814 "-" "Ruby"
87.140.79.42 - - [23/Jan/2024:09:00:46 +0100] "GET /monitoring/pings/ HTTP/1.1" 200 814 "-" "Ruby"

Goal

Count and sort the number of requests for a single IP address.

Bash Command

awk '{ print $1}' test.log | sort...

Example

I, [2024-01-21T06:22:17.484221 #2698200]  INFO -- : [4cdad7a4-8617-4bc9-84e9-c40364eea2e4] test
I, [2024-01-21T06:22:17.484221 #2698200]  INFO -- : [4cdad7a4-8617-4bc9-84e9-c40364eea2e4] more
I, [2024-01-21T06:22:17.484221 #2698200]  INFO -- : [6e047fb3-05df-4df7-808e-efa9fcd05f87] test
I, [2024-01-21T06:22:17.484221 #2698200]  INFO -- : [6e047fb3-05df-4df7-808e-efa9fcd05f87] more
I, [2024-01-21T06:22:17.484221 #2698200]  INFO -- : [53a240c1-489e-4936-bbeb-d6f77284cf38] nope
I, [2024-01-21T06:22:17.484221 #2698200]  INFO -- ...

There are a few tools to combat the dreaded n+1 queries. The bullet gem notifies you of missing eager-loading, and also if there is too much eager-loading. strict_loading in Rails 6.1+ forces developers to explicitly load associations on individual records, for a single association, for an entire model, or globally for all models.

But you can also actually **write spe...

Today I learned that you can animate HTML elements using the Web Animation API's method .animate(keyframes, options) (which seems to be Baseline for all browsers since 2022).

const fadeIn = [{ opacity: 0 }, { opacity: 1 }] // this is a keyframe example

const container = document.querySelector('.animate-me')

const animation = container.animate(fadeIn, 2000) // I am just using the animation duration as option here but it can also be given an object

// the animation object can be used for things like querying timings or stat...

Adding a unit

Multiply by 1x the unit:

$number = 13
$length = $number * 1px // => 13px

Removing a unit

Divide by 1x the unit:

$length = 13px
$number = $length / 1px // => 13

Converting a unit

the result of an addition or subtraction between two numbers of different units is expressed in the first member’s unit

Thus, to convert a number, add it to 0 of the desired unit:

$duration: .21s
$duration-in-milliseconds: 0ms + $duration // => 210ms

An example is storing a transition duration as CS...

Ruby methods which load from a Yaml file, like YAML.safe_load or YAML.safe_load_file, support passing freeze: true to deep-freeze the entire contents from the Yaml file.
This is available by default on Ruby 3.0 and newer. On older Rubies, you can install psych 3.2.0 or newer for :freeze support.

As an example, consider the following Yaml file:

---
message:
  - hello
  - universe
foo:
  bar:
    baz: "example"

We can now load it as usual, but pass freeze: true.

>> test = YAML.safe_load_file('example.yml', fre...

Your development server is usually running on an insecure HTTP connection which is perfectly fine for development.

If you need your local dev server to be accessible via HTTPS for some reason, you need both a certificate and its key. For a local hostname, you need to create those yourself.
This card explains how to do that and how to make your browser trust the certificate so it does not show warnings for your own certificate.

Easy: self-signed certificate

To just create a certificate for localhost, you can use the following command....

We generally use multiple application servers (at least two) and you have to search on all of them if you don't know which one handled the request you are looking for.

Rails application logs usually live in /var/www/<project-environment-name>/shared/log.
Web server logs usually live in /var/www/<project-environment-name>/log.

Searching through single logs with grep / zgrep

You can use grep in this directory to only search the latest logs or zgrep to also search older (already zipped) logs. zgrep is used just like grep ...

Note: Modern Rails has two build pipelines, the asset pipeline (or "Sprockets") and Webpacker. The principles below apply for both, but the examples shown are for Sprockets.

Every page in your application uses many assets, such as images, javascripts and stylesheets. Without your intervention, the browser will request these assets again and again on every request. There is no magic in Rails that gives you automatic caching for assets. In fact, if you haven't been paying attention to this, your application is probabl...

Phusion Passenger changed the way how it gets restarted several times. Through the project's history, these all were valid:

• touch tmp/restart.txt
• sudo passenger-config restart-app /path/to/app
• passenger-config restart-app /path/to/app

You should not need to know which one to use. Instead, the capistrano-passenger gem will choose the appropriate restart mechanism automatically based on your installed the passenger version.

Installation

1. Add to your Gemfile:

   gem 'capistr...
   

Here are some hints on best practices to maintain your tasks in larger projects.

Rake Tasks vs. Scripts

• The Rails default is using rake tasks for your application tasks. These live in lib/tasks/*.
• In case you want to avoid rake for your tasks and just use plain ruby scripts, consider lib/scripts/* as folder.

Keeping tasks slim

For readability and testing it's easier to keep your tasks slim. We suggest to use folders inside the tasks or scripts folder.

Example for a task:

The slim task lib/tasks/gitlab.rb:

Version 3.7.0 broke some things in complex forms. Sorry for that. Concurrent user input is hard.

3.7.1

This change fixes two regressions for form field watchers, introduced by 3.7.0:

• When a change is detected while waiting for an async callback, prevent the new callback from crashing with Cannot destructure property { disable } of null.
• When a change is detected while waiting for an async callback, the full debounce delay of that new change is honored.

...

If you have an element with significant border-radius (e.g. 50% for a circle) and you want inline content (i.e. text) to flow around it, do it like this:

• Place the element right before the text and float: right or float: left
• Tell the browser to take the content-box for the element's shape, i.e. without margin, padding and border. shape-outside: content-box
• Set the margin where you want it, e.g. 10px left and bottom
• Set the shape-margin to the same size ...