In an environment:

config.logger = Logger.new('/dev/null')

In medium-sized to large Rails applications, asset compilation can take several minutes. In order to speed up deployment, asset precompilation can be skipped. This card automates the process.

Capistrano 3

```
namespace :deploy do

desc 'Automatically skip asset compile if possible'
task :auto_skip_assets do
asset_locations = %r(^(Gemfile.lock|app/assets|lib/assets|vendor/asset))

revisions = []
on roles :app do
  within current_path do
    revisions << capture(:cat, 'REVISION').strip
  ...

The problem

Calling bundle update GEMNAME will update a lot more gems than you think. E.g. when you do this:

bundle update cucumber-rails

… you might think this will only update cucumber-rails. But it actually updates cucumber-rails and all of its dependencies. This will explode in your face when one of these dependencies release a new version with breaking API changes. Which is all the time.

In the example above updating cucumber-rails will give you Capybara 2.0 (because capybara is a dependency of `cucumber-rail…

The Edge Rider gem gives your relations a method #traverse_association which
returns a new relation by "pivoting" around a named association.

Say we have a Post model and each Post belongs to an author:

class Post < ActiveRecord::Base
  belongs_to :author
end

To turn a relation of posts into a relation of its authors:

posts = Post.where(:archived => false)
authors = posts.traverse_association(:author)

You can traverse multiple associations in a single call.
E.g. t…

Add a user with password

mysql -uroot -p
CREATE USER 'newuser'@'localhost' IDENTIFIED BY 'changeme';
GRANT ALL PRIVILEGES ON * . * TO 'newuser'@'localhost';
FLUSH PRIVILEGES;
exit;

Add a user without password

mysql -uroot -p
CREATE USER 'newuser'@'localhost' IDENTIFIED BY '';
GRANT ALL PRIVILEGES ON * . * TO 'newuser'@'localhost';
FLUSH PRIVILEGES;
exit;

If you don't have a user with the sufficient access rights, follow these steps to reset…

CoffeeScript and JavaScript (ECMAScript) both have operators in and of. Each language use them for more than one purpose. There is not a single case where the same operator can be used for the same purpose in both languages.

Check if an object (or its prototype) has a property

CoffeeScript

var hasFoo = 'foo' of object

JavaScript

var hasFoo = 'foo' in object;

Iterate through all properties of an object
================================…

Browsers' printing methods usually don't print background colors. In most cases this is the desired behavior, because you don't want to spent tons of ink printing the background of a web page. But in some cases you want to print the background color of elements, e.g. bars of a chart. For those elements you need to set the following css styles:

Chrome and Safari:

-webkit-print-color-adjust: exact;

Firefox:

color-adjust: exact;

This card existed before, but was outdated due to browser implementation changes. The information below is validated for the current list of browsers we support.

By default your html and body elements are only as high as the actual page content. If you only have two lines of text in your page, your html and body elements will only be around 40 pixels high, regardless of the size of your browser window.

You might be surprised by this, since setting a background on either html and body does cover the enti…

There is a kinda secret, yet well supported CSS feature called currentColor. It's like a special CSS variable that has been supported in almost all browsers for almost all time (see linked Caniuse).

Usage

The currentColor value can be used in CSS to indicate the current value of color should be used. A common use case is setting a border color:

a.ghost
  color: white
  border: 1px solid currentColor
  &:hover
    color: red // Border color will change as well 

Note that in many cases, you can simply omit the color to ac…

Definition

A matcher is a function that returns an object with a compare key. Usually it is registered with beforeEach:

beforeEach ->
  jasmine.addMatchers
  
    # Example matcher
    toBeAnything: ->
      compare: (actualValue, matcherArguments...) ->
         # Do some computations here ...
         
         # Return whether the actualValue matches the expectation
         pass: true

Usage

expect(actualValue).toBeAnything(matcherArguments...)

When a matcher is invoked, Jasmine will call its compare() fu…

TL;DR There are three dimensions you can control when scoping routes:

scope module: 'module', path: 'path', as: 'as' do
  resources :examples, only: :index
end

=> Path Helpers: as_examples_path and as_examples_url
=> URLs: /path/examples
=> Controller module: Module::ExamplesController and views location: app/views/module/examples/

Changing URLs only

When you want to namespace some paths but leave the corresponding controllers and url helpers unaffected, you can use the scope method like follows:

```
scope path…

Just like Ruby Gems tag their version releases to the corresponding Git commit, it can be helpful to track production deploys within the commit history. This task does the tagging for you.

Capistrano 3

# lib/capistrano/tasks/deploy.rb
namespace :deploy do
  ...

  desc 'Tag the deployed revision'
  task :tag_revision do
    date = Date.today.to_s

    puts `git tag deploy-#{date} #{fetch :current_revision}`
    puts `git push --tags origin`
  end

end

```
# config/deploy/production.rb
after 'deploy:finished', 'deploy:tag_revi…

Authentication is hard: there are many edge cases, and most users (including yourself) usually only go the "happy path" once and never see the edge cases. If you have rolled your own authentication, or been using older authentication solutions, or resorted to HTTP Basic Authentication, this card will tell you what to do to make your application safe.

Any application that stores sensitive data in the browser

That is: cookies, e.g. by offering a login.

• Ask the admins to [turn on SSL](https://makandracards.com/makandra/1416-integrate-s…

Since images are magnitudes larger in file size than text (HTML, CSS, Javascript) is, loading the images of a large web page takes a significant amount of the total load time. When your internet connection is good, this is usually not an issue. However, users with limited bandwidth (i.e. on mobile) need to mine their data budget better.

One popular strategy to improve the website performance is to not load images until they enter the viewport – aka "lazy-loading images".

General Issues

• Crawlers do not execute JavaScript (generally sp…

Installing ruby 1.8.7 with rbenv might fail if you have installed libssl-dev instead of libssl1.0-dev (default in Ubuntu 18.04).

Run sudo apt install libssl1.0-dev to remove libssl-dev and add libssl1.0-dev.

You can check installed libssl packages using apt list:

```
$ apt list –installed | grep libssl

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

libssl-dev/bionic,now 1.1.0g-2ubuntu4 amd64 [installed]
libssl-doc/bionic,bionic,now 1.1.0g-2ubuntu4 all [installed,automatic]
libssl1.0.0/bion…

TL;DR Append your locale keys with _html to have them marked as html_safe.

When you're localizing a Rails application, sometimes there is this urge to include a little HTML. Be it some localized link, or a set of <em> tags, you'd like to have it included in the locale file. Example:

```
# Locale file
en:
page:
text: 'Please visit our corporate website to learn more about the corporation.'

HAML

= t('.text')

Desired output

Please visit our <a href="https://w…