Installation

You need to install the official plugin, it is not bundled with RubyMine by default.

Example: Setup a watcher to verify rubocop integrity

First, open Settings -> Tools -> File Watchers. Then, configure rubocop to check every change to the VCS:

Note that the "program" argument must be part of your $PATH. I worked around this constraint by using b as a shim for bundle exec.

Resources

• [File watchers documen...

curl-to-ruby is a handy tool that converts your curl command to ruby code that uses the Net::HTTP library.

Example

curl -X POST -d
  "grant_type=password&email=email&password=password"
  localhost:3000/oauth/token

will output to:

require 'net/http'
require 'uri'

uri = URI.parse("http://localhost:3000/oauth/token")
request = Net::HTTP::Post.new(uri)
request.set_form_data(
  "email" => "email",
  "grant_type" => "password",
  "password" => "password",
)

req_options =...

A practical and detailed walk-through tutorial on using ffmpeg for live-streaming HLS, filled with real-world examples.

• Using FFmpeg as a HLS streaming server (Part 1) – HLS Basics
• Using FFmpeg as a HLS streaming server (Part 2) – Enhanced HLS Segmentation
• Using FFmpeg as a HLS streaming server (Part 3) – Multiple Bitrates
• Using FFmpeg as a HLS streaming server (Part 4) – Multiple Video Resolutions
• Using FFmpeg as a HLS streaming server (Part 5) – Folder Structure
• Using FFmpeg as a HLS streaming server (Part 6) – Independent Seg...

In Rubocop you might notice the cop Style/CaseEquality for e.g. this example:

def foo(expected, actual)
  expected === actual
end

In case expected is a Regex, it suggests to change it to the following pattern:

def foo(expected, actual)
  expected.match?(actual)
end

In case expected is a Regex or a String, you need to keep ===. Otherwise the actual expression is always converted to a regular expression.

# For expected === actual
foo('Test(s)', 'Test(s)') #=> true

# For expected.match?(actual)
foo('Test(...

Scroll and touch event listeners tend to be computationally expensive as they are triggered very often. Every time the event is fired, the browser needs to wait for the event to be processed before continuing - the event could prevent the default behavior. Luckily there is a concept called passive event listeners which is supported by all modern browsers.

Below are the key parts quoted from WICG's explainer on passive event listeners. See [this demo video](https://www.youtube.com/watch?v=NPM6172...

Here is a short summary of Cucumber hooks in Ruby taken from https://github.com/cucumber/cucumber-ruby. Note that the BeforeStep is currently not existing in the Ruby implementation of Cucumber.

Before hooks run before the first step of each scenario.

Before do |scenario|
  ...
end

After hooks run after the last step of each scenario, even when the step result is failed, undefined, pending or skipped.

...

Sometimes you want to find the inverse of an ActiveRecord scope. Depending on what you want to achieve, this is quite easy with Rails 7, and a bit more complicated with Rails 6 and below, or when the inverse scope may contain NULL values. [1]

There are two different ways of "inverting a scope":

As an example, consider the following model.

class User < ApplicationRecord
  scope :admins, -> { where(role: ['admin', 'superuser']) }
  # ...
end

Mathematical NOT

You know this one from basic set theory. It proces the "complementa...

Ubuntu 18.04 uses systemd to manage services.

There are basically two commands for listing all services and manipulating the state of a certain service: service and systemctl:

• service manages System V init scripts
• systemctl controls the state of the systemd system and service manager. It is backwards compatible to System V and includes the System V services

Therefore I prefer to use systemctl.

See which services are there

>systemctl list-units -a --type=service
  UNIT                                 LOAD     ...

We currently test most of our gems on Travis CI, but want to migrate those tests to Github Actions. This is a step-by-step guide on how to do this.

Note that this guide requires the gem to use gemika.

1. Go to a new "ci" branch:

   git checkout -b ci
   

2. Update gemika to version >= 0.5.0 in all your Gemfiles.
3. Have gemika generate a Github Actions workflow definition by running

   mkdir -p .github/workflows; bundle exec rake gemika:generate_github_actions_workflow > .github/workf...
   

While debugging a SPF record I found spf-record.de to be very helpful.

• it lists all IPs that are covered by the SPF record
• shows syntax errors
• helps you debugging errors like DNS lookup limit reached
• it also lets you test a new SPF strings before applying it. This can save you time as you don't have to loop with operations

Also the advanced check at vamsoft.com has a very good interface to test new SPF policies.

When loading a database dump created with pg_dump into your database, you might run into an error like

pg_restore: error: unsupported version (1.15) in file header

This is because your local pg_restore version is too old to match the format created by pg_dump. The version of the PostgreSQL server doesn't matter here.

For example, the official Ubuntu 20.04 sources include only PostgreSQL 12, so your pg_restore version will also be v12. Ubuntu 22.04 includes version 14 in its sources.
Both seem to be incompatible with dumps ...

It sometimes happen that a database dump, that would want to insert into your development database, does not match the current schema of the database. This often happens when you have an old dump, but your current setup is up to date with the the master.

Hint: In most cases it is sufficient to delete and recreate the local database in order to import the dump. If any problems occur, proceed as follows:

1. Figure out the original migration status of the dumpfile

• Convert your dump to plaintext: `pg_restore -f some.dump > some.dump....

The sidekiq-rate-limiter gem allows rate-limiting Sidekiq jobs and works like a charm. However, it needs to be integrated on a per-worker basis.

If you want to limit a whole queue instead, and if your requirements are simple enough, you can do it via a Sidekiq middleware yourself.

Here is an example that limits concurrency of the "mailers" queue to 1. It uses a database mutex via the [with_advisory_lock](https://github.com/ClosureTree/wit...

If you're using the webdrivers gem and VCR together, depending on your configuration, VCR will yell at you regulary.
The webdrivers gem tries to update your webdrivers on your local machine. To do so, it checks the internet for newer versions, firing an HTTP-request to e.g. https://chromedriver.storage.googleapis.com

You can "fix" this in multiple ways:

1. Update your drivers on your machine with
   RAILS_ENV=test rake webdrivers:chromedriver:update

2. Ignore the driver update-URL in your ...

Good reference how to build bootstrap forms with simple_form.

When logging in Rails, you can use the log_tags configuration option to add extra information to each line, like :request_id or :subdomain. However, those are only valid inside a request context and have no effect when your application is logging from inside a Sidekiq process.
This includes custom as well as any framework logs, like query logging from ActiveRecord.

Since Sidekiq Workers run inside threads of a single process, running multiple jobs in...

ActiveRecord provides the ids method to pluck ids from a scope, but what if you need to pluck Global IDs?

While you could just call map(&:to_global_id) on your scope, this approach would instantiate each record just to do that. When you have many records, this will at the very least be slow.

Here is a method that does it for you efficiently. It respects Single Table Inheritance (STI).
Put it in your project's ApplicationRecord to make it available on all models.

class ApplicationRecord
  ...

If you want to get the path of a file relative to another, you can use the expand_path method with either the constant __FILE__ or the method __dir__. Read this card for more information about __FILE__ and __dir__.

Example

Structure:

.
├── bin
│   ├── format_changelog
├── CHANGELOG.md

bin/format_changelog:

#!/usr/bin/env ruby

changelog_path = ? # How to get the path to ../CHANGELOG.md independent of the working dir of the caller
changelog = File.read(changelog_path)

# ... further actions...

Development

Google Chrome disables Notifications for insecure origins (i.e. those using HTTP). Only http://localhost is considered secure.

If you need to use browser notifications on other origins, you can set a flag: chrome://flags/#unsafely-treat-insecure-origin-as-secure. Enable the flag and add your origins. Remember that "origin" refers to the combination of protocol+hostname+port, e.g. "http://example.com:8088".

CSS variables are very different from preprocessor variables. While preprocessors use variables to compile a static piece of CSS, CSS custom properties are a reactive (i.e. live) part of the styles. Think of them like usual CSS properties that cascade, but have:

• A special syntax: CSS variables always start with a double-dash (--color)
• No inherent meaning: Defining a CSS variable will not change any styles in itself
• A special functionality: CSS variables can be used within the values of other properties, including CSS variables...

When you use Sentry to monitor exceptions, an important feature is Sentry's error grouping mechanism. It will aggregate similar error "events" into one issue, so you can track and monitor it more easily. Grouping is especially important when you try to silence certain errors.

It is worth understanding how Sentry's grouping mechanism works.

The default grouping mechanism

The exact algorithm has changed over time, and Sentry will keep using the algorithm t...

In Ruby on Rails, all the routes of a given application can be found within the config/routes.rb file.
You add more and more routes in this file as your project grows.

The problem here is that this file potentially becomes very complicated to manage over the time.
That’s why it’s important to find a way to order and maintain your routes.

See: Clean your Rails routes: grouping

Sometimes the routes.rb grows very fast and each line adds mo...

When writing some logs to a file, that don't use Ruby's logger utility, it is often useful to sync them. So other process can read the output just in time.

Example with enabled sync

log_path = '/tmp/some_log.log'

log_file = File.open(log_path, 'a+')
log_file.sync = true

log_file.puts('Some log message')
File.read(log_path) #=> "Some log message\n"

log_file.puts('Some other message')
File.read(log_path) #=> "Some log message\nSome other message\n"

Example ...

Here is an example with the --tags option. You need to wrap them inside --cucumber-options option of parallel_cucumber.

DISPLAY=:17 bundle exec parallel_cucumber --cucumber-options '--tags @solo' features

See more details in the docs.