Sometimes it's nice to have some coloring in your logs for better readability. You can output your logs via tail and pipe this through sed to add ANSI color annotations (which your console then interprets).

To print a log (e.g. rails log) and color all lines containing "FATAL" in red and all lines with "INFO" in green:

tail -f /path/to/log | sed --unbuffered -e 's/\(.*INFO.*\)/\o033[32m\1\o033[39m/' -e 's/\(.*FATAL.*\)/\o033[31m\1\o033[39m/'

Here are the ...

To find an input with the type hidden, you need to specify the type hidden:

find_field('Some label', type: :hidden)

Otherwise you will see an exception :

find_field('Some label')
# => Capybara::ElementNotFound: Unable to find field "Some label" that is not disabled`.

Note: Usually you don't need to check the input of hidden fields in an integration test. But e.g. waiting for a datepicker library to write the expected value to this field before continuing the test, which prevents flaky tests, is a valid use case.

If you need to test some HTML, e.g. an embed code, you can use RubyMine's "scratch files":

1. File > New Scratch File (or Ctrl + Shift + Alt + Ins)
2. Select "HTML" as file type
3. Write or paste the HTML
4. Move your mouse to the upper right corner of the scratch file editor. Pick a browser to instantly open your file.

You can use the CSS property mask-image to define an "alpha channel" for an element.

E.g. to let an element start at full opacity at the top and gradually fade into transparency at the bottom:

.box {
  -webkit-mask-image: linear-gradient(to bottom, black 0%, transparent 100%);
  mask-image: linear-gradient(to bottom, black 0%, transparent 100%);
}

• A fully opaque black pixel will render the masked pixel fully opaque
• A fully transparent black pixel will render the ...

jQuery offers many different methods to move a selection through the DOM tree. These are the most important:

$element.find(selector)
Get the descendants of each element in the current set of matched elements, filtered by a selector. Does not find the current element, even it matches. If you wanted to do that, you need to write $element.find(selector).addBack(selector).

$element.closest(selector)
Get the first ancestor el...

TLS/SSL certificates are often used for HTTPS traffic. Occasionally a service may also use their TLS certificate to support public-key encrypting data (e.g. when it is part of the URI and visible to the user, but contains sensitive information).

Here is how to easily fetch such certificate data.

certificate = Net::HTTP.start('example.com', 443, use_ssl: true) { |http| http.peer_cert }
# => #<OpenSSL::X509::Certificate: subject=#<OpenSSL::X509::Name CN=www.example.org,...>

certificate.public_key
# => #<OpenSSL::PKey::RSA:0x...

Be careful to name any file @imported by SASS with a leading underscore.

SASS files not beginning with an underscore will be rendered on their own, which will fail if they are using variables or mixins defined elsewhere. (For me it broke only in production, which may be due to some settings in SASS-GEM/lib/sass/plugin/rails.rb.)

From the SASS docs:

The underscore lets Sass know that the file is only a partial file and that it should not be generated into a CSS file.

How to get a backtrace from a running Ruby process:

Ruby 2.6

# First, find out the PID of your Ruby process (e.g. passenger-status)
$ sudo gdb -p PID
(gdb) call rb_eval_string("$stderr.reopen('/tmp/ruby-debug.' + Process.pid.to_s); $stderr.sync = true") # redirects stderr
(gdb) call rb_backtrace() # prints current backtrace to /tmp/ruby-debug.xxx

Stop the process afterwards, since stderr is now borked.

It is possible you have to call rb_backtrace() multiple times to get the full stacktrace.

Previous method on Ruby 2....

Capistrano 2 brings the shell command which allows you to run commands on your deployment targets.
There is also invoke to run a command directly from your terminal.

Both commands allow running Capistrano tasks or shell commands, and scope to individual machines or machine roles.

Unfortunately Capistrano 3 does not include these commands any more.

cap shell

Basics

First of all, spawn a Capistrano shell (we're using the multistage extension here):

$ cap staging shell

In your "cap" shell you can now run Capistrano ta...

The linked article has a great explanation how to to deal with string encodings in Ruby. Furthermore you can check out some of our cards about encoding:

• Ruby's default encodings can be unexpected
• How to fix invalid byte sequence in UTF-8 error

Imagine you want to write a cucumber test for a user-to-user chat. To do this, you need the test to work with several browser sessions, logged in as separate users, at the same time.

Luckily, Capybara makes this relatively easy:

Scenario:

Scenario: Alice and Bob can chat
  Given Alice, Bob, and a chat session
  When I am signed in as "Alice"
    And I go to the chat
    And I am signed in as "Bob" [session: bob]
    And I go to the chat [session: bob]
    And I send the message "Hello, this is Alice!"
  Then I should see "Hello, this ...

This is a personal post-mortem analysis of a project that was mainly build to provide a REST API to mobile clients.

For the API backend we used the following components:

• Active Model Serializer (AMS) to serializer our Active Record models to JSON.
• JSON Schema to test the responses of our server.
• SwaggerUI to document the API.

It worked

The concept worked really good. Here are two points that were extraordinary compared to normal Rails project with many UI components:

• Having a Rails application, that has no UI components (only...

PostgreSQL and ActiveRecord have a good support for storing dynamic attributes (hashes) in columns of type JSONB. But sometimes you are missing some kind of validation or lookup possibility (with plain attributes you can use Active Record's built-in validations and have your schema.rb).

One approach about being more strict with dynamic attributes is to use JSON Schema validations. Here is an example, where a project has the dynamic attributes analytic_stats, that we can use to store analytics from an external measurement tool.

• A g...

Sometimes, you might have duplicate links on a page. Trying to click those links will by default cause Capybara to raise an Ambiguous match error.

If you do not care about which of those links are clicked, you can disable this errors by adding the following meta step:

When(/^(.*) \[allow ambiguous\]$/)do |step_text|
  prior_match_strategy = Capybara.match
  Capybara.match = :first
  step(step_text)
ensure
  Capybara.match = prior_match_strategy
end

Use it with

When I follow "a duplicate link" [allow ambiguous]

When you have two inputs, where one contains the name of the other (eg. Name and Name with special treatment), Capybara's fill_in method will fail with the following message:

Ambiguous match, found 2 elements matching visible field "Name" that is not disabled (Capybara::Ambiguous)

You can force Capybara to match exactly what you are typing (which makes your tests better anyways) with match: :prefer_exact:

name = 'Name'
value = 'Bettertest Cucumberbatch'
fill_in(field, with: value, match: :prefer_exact)

Furthermore...

To test that an object was constructed by a given constructor function, use jasmine.any(Klass):

describe('plus()', function() {
  it ('returns a number', function() {
    let result = plus(1, 2)
    expect(result).toEqual(jasmine.any(Number))
  })
})

Also see Expecting objects as method invocation arguments.

MySQL and MariaDB have an SQL mode setting which changes how MySQL behaves.

The SQL mode value is comprised of multiple flags like "STRICT_TRANS_TABLES, NO_ZERO_IN_DATE". Each flag activates or disables a particular behavior.

The default SQL mode varies widly between versions of MySQL and MariaDB. In general, more recent versions of MySQL and MariaDB have stricter settings than older versions, and MySQL has stricter settings than the more liberal MariaDB.

If your app explodes ...

If you want to make your Rails application be capable of sending SMTP emails, check out the action mailer configuration section in the Ruby on Rails guide.

TL;DR you will end up having an smtp_settings hash that looks something like this:

smtp_settings = {
  address: ...,
  domain: ...,
  port: ...,
  user_name: ...,
  password: ...,
  authentication: ...,
  tls: ...,
  enable_starttls_auto: ...,
}

This hash can be set as the `delivery_me...

It's every developer's nightmare: SQL queries that get large and unwieldy. This can happen fairly quickly with the addition of multiple joins, a subquery and some complicated filtering logic. I have personally seen queries grow to nearly one hundred lines long in both the financial services and health industries.

Luckily Postgres provides two ways to encapsulate large queries: Views and Materialized Views. In this article, we will cover in detail how to utilize both views and materialized views within Ruby on Rails, and we can even take...

Bundler 2 introduced various incompatibilites und confusing behavior. To add to the confusion, Bundler's behavior changed after the release of their version 2.

The linked article explains what happened.

Im using the terminator terminal with the keyboard shortcut Control+Shift+E for splitting the terminal. I got used to this shortcut.

Yesterday the Ubuntu update seems to have upgraded ibus, which got this emoji picker that also uses Control+Shift+E to open.
You can change this behaviour by opening the ibus setup from the console:

ibus-setup

A window will open and you can delete the shortcut in the emoji tab (Emoj...