The migration DSL now supports adding and removing foreign keys. They are dumped to schema.rb as well. At this time, only the mysql, mysql2 and postgresql adapters support foreign keys. @rubyonrails

Workings

add_foreign_key(:comments, :users)

adds a database constraint

ALTER TABLE "comments" ADD CONSTRAINT comments_user_id_fk FOREIGN KEY ("user_id") REFERENCES "user" ("id")

Disadvantage

Foreign key constraints double the validatio...

tl;dr: Use event.currentTarget unless you are absolutely certain that you need event.target.

Since it hasn't been written down in this deck before, here it goes:

When working with JavaScript Event objects, the DOM element that triggered the event is attached to them. [1]
However, there are 2 "opinions" on which element that would be:

• The element that the user interacted with (event.target),
• or the element that the event listener is bound to (event.currentTarget).

Note that both can be, but not...

Your after_commit callbacks will not know about changes, as Rails discards them when committing.

The linked article shows a clever trick to work around that: It uses an after_save method that looks at changes and writes its decision to an instance variable. That instance variable can then be used in the after_commit method.

Note that while callbacks like after_save are not affected, there are valid reasons for using only after_commit, and not after_save. Enqueueing a Sidekiq job is just one of them.

Rails 5+

You can use ...

This blew my mind today:

• 12 Little-Known CSS Facts
• 12 Little-Known CSS Facts (The Sequel)

Please make sure to check browser support for CSS features on Can I Use and the Mozilla Development Network before using.

Favorites

• outline-offset: specify how far away from the element an outline is rendered
• ::first-letter: matches the first letter insid...

Sometimes you need to run background jobs that you can't make important guarantees about - they may run out of memory and get killed, or produce segmentation faults, or exit! directly - and you need to be able to clean up after such problems.

IsoLatte is a gem that allows a block of code to be executed in a subprocess. Exceptions get passed back to the parent process through a pipe, and various exit conditions are handled via configurable callbacks.

Large projects usually have large test suites that can run for a long time.
This can be annoying as running tests blocks you from picking up the next story -- but it doesn't have to be that way!

Simply clone your project's repo twice (or even more often).

When your work on a feature branch is done, simply push that branch and check it out on your 2nd copy to run tests there.
You can pick up a new story and work on that on your "main" project directory.

If you do it right, you will even be able to run tests in both your 2nd copy and your m...

In most of our applications, users have their first and last name stored in separate columns. However, specifying them separately quickly gets annoying, especially when proxying them from cucumber_factory:

Given there is a user with the first name "Dominik" and the last name "Schöler"

Wouldn't it be nice if you could just say:

Given there is a user with the name "Dominik Schöler"

and have FactoryGirl assign first and last name automatically? The code below achieves that!

##...

Disabling auto-complete in login forms is probably a bad idea, since it encourages weak passwords.

If you are still forced to implement this (maybe due to legal or policy requirements), this is how:

Prevent browsers from saving the password in the first place. Disabling autocomplete does not improve security.

How to prevent password saving:

To prevent the browser from saving passwords (and usernames), you need to:

• copy username and password to hidden form fields before submitting the login form
• c...

In my RubyMine I have recorded two macros for debugging and linked them to some keyboard shortcuts. Since I believe everyone could benefit from having those I wanted to share this.

The first one simply inserts

binding.pry

and the second one

.tap { |object| binding.pry }

for when you do not have a reference to the object you want to inspect.

In order to record a macro you simply follow the path Edit > Macros > Start Macro Recording.

Then you simply type binding.pry or whatever you want to record and stop recor...

When working with ActiveType you will often find it useful to cast an ActiveRecord instance to its extended ActiveType::Record variant.

Starting with active_type 0.4.0 you can use ActiveType.cast for this:

class User < ActiveRecord::Base
  ...
end

class SignUp < ActiveType::Record[User]
  ...
end

user = User.find(1)
sign_up = ActiveType.cast(user, SignUp)
sign_up.is_a?(SignUp) # => true

This is basically like [ActiveRecord#becomes](http://apidock.com/rails/v4.2.1/ActiveRecord/...

Note: ActiveRecord::Base#becomes has a lot of quirks and inconsistent behavior. You probably want to use ActiveType.cast instead.

This issue will be encountered when relying on attribute_was methods of ActiveModel::Dirty after casting a model which has defaults to a form model, for example.

In my case a record with an assignable_values legacy value beca...

There is no such thing as a "default order" of rows in database tables.

For instance, when you paginate a result set: When using LIMIT, it is important to use an ORDER BY clause that constrains the result rows into a unique order. Otherwise you will get an unpredictable subset of the query's rows. You might be asking for the tenth through twentieth rows, but tenth through twentieth in what ordering? The ordering is unknown, unless you specified ORDER BY.

In Rails, if you use Record.first or Record.last, it will default to orderin...

HTTP/2 will make our applications faster, simpler, and more robust—a rare combination—by allowing us to undo many of the HTTP/1.1 workarounds previously done within our applications and address these concerns within the transport layer itself. Even better, it also opens up a number of entirely new opportunities to optimize our applications and improve performance!

ActiveModel supplies an errors object that behaves similar to a Hash. It can be used to add errors to a record, as well as to query the record for registered errors. This object is returned when calling <object>.errors:

errors = @user.errors # => #<ActiveModel::Errors ...>

Here are some helpful messages of its API:

[<attribute name>]

Returns an array of error messages on that attribute. Example: errors[:name] => ['is missing']

add_on_blank(<attribute list>) (similarly add_on_empty)

Registers an error ...

All major browsers (IE8+, FF3.5+, Safari 4+, any Chrome) support sessionStorage, a JavaScript storage object that

• survives page reloads and browser restores,
• but is different per new tab/window (in contrast to localStorage which is shared across all tabs).

MDN says:

The sessionStorage object is most useful for hanging on to temporary data that should be saved and restored if the browser is accidentally refreshed

Demo

Example usage:

sslscan is a nice tool to show details about TLS/SSL connections:

~> sslscan some-host-at.makandra.de

Testing SSL server some-host-at.makandra.de on port 443

  Supported Server Cipher(s):
    Failed    SSLv3  256 bits  ECDHE-RSA-AES256-GCM-SHA384
    Failed    SSLv3  256 bits  ECDHE-ECDSA-AES256-GCM-SHA384
    Failed    SSLv3  256 bits  ECDHE-RSA-AES256-SHA384
    Failed    SSLv3  256 bits  ECDHE-ECDSA-AES256-SHA384
    Rejected  SSLv3  256 bits  ECDHE-RSA-AES256-SHA
...

  Prefered Server Cipher(s):
    TLSv1  128 bits  ECDHE-RSA-A...

Capistrano 3 is a major rework of the framework and requires several adjustments to your deploy configuration files. The biggest change is that they moved away from their custom DSL and use Rake instead. For connecting with and operating on the servers, they bring a new gem SSHKit which does the heavy lifting. It's SSHKit's DSL that is used anywhere inside the Rake tasks. See #Resources at the bottom for examples.

Step 1: Upgrade guide

For migration from 2 to 3, follow this tutorial: [Capistrano 3 Upgrade Guide](https://semaphorec...

FactoryBot.define do

  factory :parent do
    transient do
      child_name nil
      child_allowed_to_drive false
    end
    
    child do
      association(:child, name: child_name, allowed_to_drive: child_allowed_to_drive)
    end
  end

  factory :child do
    name 'Child'
    allowed_to_drive false
  end

end

# Usage
daughter = FactoryBot.create(:parent, child_name: 'Lisa').child
daughter.name # => 'Lisa'
daughter.allowed_to_drive? # => false

son = FactoryBot.create(:parent, child_name: 'Benedikt', child_allowed_to_drive: tr...

When using Savon to connect a SOAP API, you may want to use Savon::SpecHelper to mock requests in your tests as described in their documentation.

When sending a message body, the savon mock object requires a message to be set, like this:

savon.expects(:action_name).with(message: { user_id: 123 }).returns('<some xml>')

If you want to stub only the returned XML and do not care about request arguments, you can not omit with as Savon's helper will complain:

savo...

Jasmine has a jasmine.clock() helper that you can use to travel through time and trigger setTimeout and setInterval callbacks:

beforeEach(function() {
  timerCallback = jasmine.createSpy("timerCallback");
  jasmine.clock().install();
});

afterEach(function() {
  jasmine.clock().uninstall();
});

it("causes a timeout to be called", function() {
  setTimeout(function() {
    timerCallback();
  }, 100);

  expect(timerCallba...

Re-creating a complex ActiveRecord scenario quickly without setting up a full-blown Rails app can come in handy e.g. when trying to replicate a presumed bug in ActiveRecord with a small script.

# Based on http://www.jonathanleighton.com/articles/2011/awesome-active-record-bug-reports/ 

# Run this script with `$ ruby my_script.rb`
require 'sqlite3'
require 'active_record'

# Use `binding.pry` anywhere in this script for easy debugging
require 'pry'

# Connect to an in-memory sqlite3 database
ActiveRecord::Base.establish_connection(
  ad...

When you want to UPDATE a table with information from an associated table, you can JOIN the associated table into the statement.

Example

Let's say you have a database schema where an Employee belongs_to :department:

+-----------------+
| Employee        |                   +------------+
|-----------------| n               1 | Department |
| email           |-------------------|------------+
| department_id   |                   | name       |
+-----------------+                   +------------+

Because of perfo...

Several Rails migration methods accept index: true as an option to create an index. In some cases (like #add_column), this option is silently discarded. Know what you are doing, or use #add_index instead.

Example

Consider the following migration.

class CreateExamples < ActiveRecord::Migration
  def change
    create_table :examples do |t|
      t.references :category, index: true
      t.boolean :positive, index: true
      t.integer :number_of_participants, index: true
    end

    add_reference :examples, :user, index: tr...