• Reading a URL via GET:

  curl http://example.com/
  

• Defining any HTTP method (like POST or PUT):

  curl http://example.com/users/1 -XPUT
  

• Sending data with a request:

  curl http://example.com/users -d"first_name=Bruce&last_name=Wayne"
  

  If you use -d and do not set an HTTP request method it automatically defaults to POST.

• Performing basic authentication:

  curl http://user:password@example.com/users/1
  

• All together now:

  curl http://user:password@example.com/users/1 -XPUT -d"screen_name=batman"
  

...

Webpack is the future. We're using it in our latest Rails applications.

For tests, we want to compile assets like for production.
For parallel tests, we want to avoid 8 workers compiling the same files at the same time.
When assets did not change, we do not want to spend time compiling them.

Here is our solution for all that.

Its concept should work for all test suites.

Copy the following to config/initializers/webpacker_compile_once.rb. It will patch Webpacker, but only for the test environment:

# Avoid hardcoded asset host...

Recently I made an upgrade from Bootstrap 3 to Bootstrap 4 in a bigger project. Here are some tips how to plan and perform such an upgrade. The effort will scale with the size of the project and its structure. If your stylesheets already follow strict rules, it may take less time to adapt them to the new version.

Preparation

There are several gems and libraries that works well with bootstrap or provide at least stylesheets/plugins to easily integrate the bootstrap theme. But very often they only work with specific version or are no long...

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...

While verifying doubles in RSpec is a good default, it is limited in the amount of methods it actually is able to verify.

The background is that RSpec can't verify dynamically defined methods, which is a known issue for the usage of helper_method and also the reason why [RSpec >= 3.6](http://rspec.info/blog/2017/05/rspec-3-6-has-been-rel...

Bundler allows you to specify the name of the Gemfile you want to bundle with the BUNDLE_GEMFILE environment variable.

BUNDLE_GEMFILE=Gemfile.rails.7.2 bundle

By default, bundler will look for a file called Gemfile in your project, but there may be cases where you want to have multiple Gemfiles in your project, which cannot all be named Gemfile. Let's say for example, you maintain a gem and want to run automated tests against multiple rails versions. When you need to bundle one of your secondary Gemfiles, the solution above ...

... you probably have a time zone issue.

When you get

Timecop.travel(Date.parse("2011-11-11 00:00") do
  Time.current  # Thu, 10 Nov 2011 23:00:01 UTC +00:00
  Time.now      # Fri Nov 11 00:00:02 +0100 2011
  Date.today    # Fri, 11 Nov 2011
  Date.tomorrow # Fri, 11 Nov 2011
end

you probably haven't defined a zime zone yet.

So might fix this by adding the following lines to your application.rb:

class Application < Rails::Application
  config.time_zone = 'Berlin' # or whatever your time zone
end

It se...

When changing code in mailers, updating the corresponding mailer preview can be forgotten very easily.

Mailer previews can be tested like other code as well and I sometimes add the following tests to test suites:

# Make sure to require the previews
Dir[Rails.root.join('spec/mailers/previews/*.rb')].each { |file| require(file) }


ActionMailer::Preview.all.index_with(&:emails).each do |preview, mails|
mails.each do |mail|
    describe preview do
      specify "##{mail} works" do
        expect { preview.call(mail...

When accepting GIF images, you will also accept animated GIFs. Resizing them can be a time-consuming task and will block a Rails worker until the image is processed.

Save yourself that trouble, and simply tell ImageMagick to drop any frames but the first one.

Add the following to your uploader class:

process :remove_animation

private

def remove_animation
  if content_type == 'image/gif'
    manipulate! { |image| image.collapse! }
  end
end

You may also define that process for specific versions only (e.g. only for thum...

When you need to see the content of a page (i.e. not all the HTML but the relevant text body)

• you can do pp (html_content)
  • pp will format the html String human readable pretty printed
• where html_content can be replaced by one of the following commands:

Rails

body or response.body

Capybara:

• page.driver.html.content
• page.body

Webrat:

Nokogiri::HTML(response.body).content

The returned strings can be cleaned up by calling .gsub(/^\s*$/, '').squeeze("\n") on them.\
Although this may be useful for d...

When RSpecs runs the first feature spec, you may see log output like this:

Capybara starting Puma...
* Version 6.5.0, codename: Sky's Version
* Min threads: 0, max threads: 4
* Listening on http://127.0.0.1:39949

You can disable this behavior by tweaking Capybara's Puma server in your spec/support/capybara.rb:

Capybara.server = :puma, { Silent: true }

Note

You don't need to configure this if you're using system tests with modern versions of Rails. They do [exactly the same](https://github.com/rails/rails/blob/ma...

Given there is a user with an attachable avatar:

class User < ApplicationRecord
  has_one_attached :avatar
end

If you want to add a preprocessed version follow these steps:

1. Add the named version and deploy

class User < ApplicationRecord
  has_one_attached :avatar do |attachable|
    attachable.variant :preview, resize_to_fit: [177, 177 * 9 / 16], preprocessed: true
  end
end

2. Preprocess this version for all existing records `bundle exec rails runner 'User.find_each { |user| user.avatar.variant(:preview).proc...

Looks simpler than inaction_mailer:

gem install mailcatcher
mailcatcher

Setup Rails to send mails to 127.0.0.1:1025. Usually you want the following config in config/environments/development.rb and maybe in test.rb or cucumber.rb.

config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  :address => 'localhost',
  :port => 1025
}

Now you can see sent mails in your browser when opening http://127.0.0.1:1080

Note: In order to s...

Webpacker uses Babel and Webpack to transpile modern JavaScript down to EcmaScript 5. Depending on what browser a project needs to support, the final Webpack output needs to be different. E.g. when we need to support IE11 we can rely on fewer JavaScript features. Hence our output will be more verbose than when we only need support modern browsers.

Rails 5.1+ projects often use Webpacker to preconfigure the Webpack pipeline for us. The default configuration works something like this:

1. Webpack checks w...

Introduction

Most of the time it is a tedious task to apply a code style guide to an existing code base as there are likely to be a lot of conflicts. At makandra we are using makandra-rubocop to have code style checks. Here is some advice on how to add makandra-rubocop efficiently.

Note

RubyMine by default has a Rubocop inspection with rules that we don't always agree with. We recommend replacing this with makandra-rubocop or disabling the inspection.
...

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...

The linked GitHub repository is a bit like our "dev" cards deck, but groomed from a single person (Josh Branchaud). It includes an extensive list of over 900 TILs on many topics that might be interesting for most of us. (e.g. Ruby, Rails, Git, Unix..)

Ruby

Here is an excerpt of all the Ruby TILs that were new to me. I encourage you to take your time to skim over the original list as well!

• Assoc For Hashes
  • `Hash#ass...

Rails 6.1 has a "strict loading" mode that forces the developer to preload any association they plan to use. Associations no longer load lazily. An error is raised when reading an association that was not preloaded.

Enabling strict loading is a tool to prevent n+1 queries.

Strict loading can be enabled for individual records, for a single association,...

In Selenium features the server and client are running in separate processes. Therefore, when mocking time with a tool like Timecop, the browser controlled by Selenium will still see the unmocked system time.

timemachine.js allows you to mock the client's time by monkey-patching into Javascript core classes. We use timemachine.js in combination with the Timecop gem to synchronize the local browser time to the ...

How it works

See the lemonade descriptions.

Unfortunately, the gem has a few problems:

• it does not work with Sass2
• it always generates all sprites when the sass file changes, which is too slow for big projects
• it expects a folder structure quite different to our usual

All these problems are solved for us, in our own lemonade fork. This fork has since been merged to the original gem, maybe we can use t...

In a nutshell:

If you require your Rails models manually, pay attention to the path you use. Unless you have to, don't do it at all.

Background

Consider these classes:

# app/models/user.rb

class User < ActiveRecord::Base
  validate :magic

  def magic
    errors.add_to_base('failed') if bad_things?
  end
end

^
# app/models/foo.rb

require 'user'

class Foo
  # something happens here
end

Now, when your environment is booted, Rails will automatically load your models, like User...

tl;dr: Do not use merge! for session hashes. Use update instead.

Outline

Let's assume you're modifying the Rails session. For simplicity, let's also assume your session is empty when you start (same effect when there is data):

# In our example, we're in a Rack middleware
request = Rack::Request.new(env)
request.session.merge! :hello => 'Universe'
request.session
=> {}

Wat?

Even worse: When you inspect your request.session like above (e.g. in a debugger shell, o...

Debugging your integration tests, that run a headless Chrome inside a docker image, is tricky.

In many cases you can connect your Chrome to a remote docker container like docker-selenium, which should be the preferred way when you try to inspect a page within your integration test.

Otherwise you might be able to start your docker container with --net=host and access your local chromedriver in the host address space host.docker.internal.

If both options above don't work for you here is a...

This card explains how to install RubyMine for the first time. If you want to upgrade an existing RubyMine installation (after legacy install) to a newer version, see How to upgrade RubyMine.

Option A (new way)

Ubuntu 16.04 comes with snap, a way to package software with all its dependencies. RubyMine is also packaged as a snap.

A snap will always track a channel (like stable, beta) and automatically update to the newest version available in this channel. By default the snap daemon will check for ...