If you run a Rails app that is using Turbo, you might observe that your integration tests are unstable depending on the load of your machine. We have a card "Fixing flaky E2E tests" that explains various reasons for that in detail.

Turbo currently ships with three modules:

• Turbo Drive accelerates links and form submissions by negating the need for full page reloads.
• Turbo Frames decompose pages into independent contexts, which scope navigation and can be lazily loaded.
• T...

GitLab has a RubyMine plugin that enables you to review and process merge requests within RubyMine!

Setup

1. Open RubyMine settings (Ctrl + Alt + S) > Plugins > Search for "GitLab" > Install
   • (You might need to re-open settings afterwards.)
2. In the RubyMine settings > Version Control > GitLab > Connect your GitLab account with "+"

Working with merge requests

1. From the Actions menu (Ctrl + Shift + A), choose "View merge requests" (with GitLab icon)
2. From the subtle dropdown, select the correct origin. Confirm with "View Me...

SimpleForm comes with an option browser_validations which could be used to give fields that have a presence validation the HTML required attribute. We usually turn it off due to difficulties controlling its behavior and appearance. Instead we only mark required fields with an asterisk (*) next to its label. Blind users probably only discover the validation issue after submitting the form due to the now displayed error messages.

A compromise with better acce...

RSpec examples can get quite long, especially in feature specs. This makes them hard to read & understand. Also, when executing them, it may take seconds to see any progress.

To improve this, I have successfully been using a little "step" helper in my tests. It marks semantic sections, structuring an example while improving documentation. When the test runs, each step prints its message (or a dot, depending on your formatter).

# spec/support/step_helper.rb
module StepHelper

  # Use this helper to label groups of related actions in l...

Frontend performance and user experience are orthogonal to feature development. If care is not taken, adding features usually degrades frontend performance over time.

Many years, frontend user experience has been hard to quantify. However, Google has developed some metrics to capture user experience on the web: the Web Vitals. The Core Web Vitals are about "perceived loading speed" (Largest Contentful Paint), reactivity (Interaction to Next Paint) and visual stability (Content Layout Shift).

I have recent...

The DB schema is the most important source of truth for your application and should be very self-explanatory. If determining the true meaning of a DB column requires historical research in your issue tracker or reverse engineering of your source code you might consider adding a comment.

Both PostgreSQL and MySQL support comments in the DB schema:

• For new columns: https://guides.rubyonrails.org/active_record_migrations.html#comments
• Changing the comment for existin...

We usually ship applications that self-host webfonts to comply with GDPR.

Many popular web fonts are available as NPM packages provided by Fontsource.
We recommend using those instead of downloading and bundling font files yourself. (See below for a list of benefits.)

Usage

1. Go to fontsource.org and search for the font you want to add (or a font that suits your application).
2. Click the font card to vie...

Even if you don't make any beginner mistakes like N+1 queries or missing DB indices, some requests can have bad performance. Without good performance metrics, you probably won't notice this until it's too late.

We investigated multiple gems and found that rails_performance (https://github.com/igorkasyanchuk/rails_performance) provides a lot of valuable information with very little setup cost. It only needs Redis which we use in the majority of our applications anyw...

tl;dr

Set profile.password_manager_leak_detection to false in your Selenium Chrome options to disable password leak detection and suppress the warning.

Problem

When running Selenium tests with recent versions of Chrome and Chromedriver (e.g., version 136+), entering “unsafe” (weak or reused) passwords in forms triggers a browser warning:

"This password has appeared in a data breach…"

This alert can break automated test runs, especially in CI/CD pipelines.

Solution

You can **disable Chrome’s password leak ...

It can be hard to understand what causes a browser scroll smoothly or instantly. CSS, JavaScript and the browser settings all have options to influence the scroll behavior. They all interact with each other and sometimes use the same words for different behavior.

CSS

Scrolling elements can use the scroll-behavior CSS property to express a preference between smooth and instant scrolling.

Preferring instant scrolling

CSS can prefer instant scrolling behavior:

html {
  scroll-behavior: auto; /* the default */
}

An `aut...

Say you wrap your index view in a form to apply different filters like pagination or a search query. On submit, your index view changes when the filters are applied (through up-submit and up-target). Now you want to enable more data-specific filters using a separate "Filters" button that opens a popup to not overload your UI.

Filter bar:

Filter popup:

The problem is tha...

For Selenium tests, your browser starts in your local timezone, or whatever your system's environment specifies.
This is usually good enough. To test any timezone-dependent behavior in Chrome, you can change the time zone using the Chrome DevTools Protocol.

Example

Chrome accepts any IANA time zone name, like "Europe/Berlin" or "Asia/Tokyo".
Here is the relevant command for Capybara:

page.driver.browser.execute_cdp('Emulation.setTimezoneOverride', timezoneId: 'Asia/Tokyo')
``...

Here is a workaround for when you want to use text-wrap: balance but must also render nicely for browsers that don't support it (mostly Safari <17.5).

Step 1: Put some <br>s into your HTML

First, place explicit line breaks that should work for most cases.
This depends on your use case and is affected by e.g. container widths or user content.

<div class="my-element">
  <p>
    Average score
    <br>
 ...

DirectUpload allows you to upload files to your file storage without having to wait for the form to submit. It creates AJAX requests to persist the file within your form and wraps them in a little API. This card will show you how to use it in order to create in-place file uploads with progress and a remove button.

This is basic functionality, you may add additional elements, styles and logic to make this look fancy, but the core functionality is the same. I created a file upload that looks like this:

![Image](/makandra/625023/attachments/3...

ActiveStorage does not provide any built-in way of implementing authentication for the available DirectUpload endpoint in Rails. When using DirectUpload as JS wrapper in the frontend, be aware that its Rails endpoint is public by default, effectively allowing anyone to upload an unlimited amount of files to your storage.

The DirectUploadController from @rails/activestorage bypasses your form controller because it uploads the file using an AJAX request that runs directly, before any form roundtrip happens. This is a comfortable solutio...

Method delegation in Rails can help you to keep your code organized and avoid deep call chains (law of demeter) by forwarding calls from one object to another. Rails provides several ways to accomplish this. Below is a concise overview of the most common approaches:

Single-Method delegation with delegate

Use the built-in delegate method from ActiveSupport to forward specific methods:

class User < ApplicationRecord
  has_one :profile

  delegate :full_name, :age, to: :profile, prefix: true
end

• `delegate: full_name, :age...

Haml renders HTML with indentation reflecting the nesting level of elements. When it comes to white-space preserving content, this may become a problem: the content will be rendered including the HTML indentation.

Problematic: Preserved Indentation

.nest
  %span Reference
  %pre
    = content

<div class="nest">
    <span>Reference</span>
    <pre>
        Hello
        World
    </pre>
</div>

Better: Without Extra Indentation

Render with tilde ~ instead of equal...

The key to unlocking the full potential of LLMs in coding lies in crafting precise prompts. The main challenge is learning how to structure prompts effectively to guide the model toward accurate results. Further evidence supporting this is the fact that Aider already writes ~70% of its own code (as of 02/2025). However, when starting out, your results may fall short of efficiently generating large portions of your code with the...

When debugging slow SQL queries, it’s helpful to understand the database engine's query plan. Whenever you execute a declarative SQL query, the database generates a "query plan" that outlines the exact steps the engine will take to execute the query. Most of the time, we don’t need to worry about this plan because SQL engines are highly optimized and can generate efficient execution strategies automatically. However, if a query is slow, inspecting the generated plan can help identify bottlenecks and optimization opportunities.

If you're usi...

Hint

If you are using our opscomplete.com hosting we can set all environment variables mentioned below for your deployment on request.

If you're lucky DO_NOT_TRACK=1 opts you out of CLI telemetry - it's not widely adopted. When you're using any of the libraries below, I'd rather opt out explicitly:

Yarn

https://yarnpkg.com/advanced/telemetry (Since: Version 2.2)

Disable for a project:

#...

Rails wraps your parameters into an interface called StrongParameters. In most cases, your form submits your data in a nested structure which goes hand in hand with the strong parameters interface.

Example:

curl -X POST -d "user[name]=bob" https://example.com/users

class UsersController
  def create
    User.create!(params.expect(user: [:name])) # Or User.create!(params.require(:user).permit(:name))
  end
end

This works well most of the time...

Also see the list of IRB commands.

Switching the context

Changes the "default receiver" of expressions. Can be used to simulate a "debugger situation" where you are "inside" an object. This is especially handy when needing to call private methods – just invoke them, no need to use send.

• Switch to an object: chws $object
• Reset to main: chws
• Show current context: cwws (usually shown in IRB prompt)

[Technical details](https://technology.doximity.com/articles/the-hidden-gems-of-r...

Some key highlights and points from the linked article TestProf II: Factory therapy for your Ruby tests.

The Problem with Factories in Ruby Tests

• Factories are used to easily generate test data.
• However, they can unintentionally slow down test suites by creating unnecessary or excessive associated data (factory cascades).

Understanding Factory-Induced Slowdowns

• Factories often create additional data (e.g., associated records) th...