Forem: Igor Kasyanchuk

Sparkline charts in Ruby on Rails app

Igor Kasyanchuk — Sat, 07 May 2022 15:46:14 +0000

Hello, just want to present our new gem: https://github.com/railsjazz/peity_vanilla_rails

If you need something like below:

You can generate it with one line of code:

<%= peity_line_chart([115,123,234,-113,-43,-223,127,332,152,233]) %>

It works without any 3rd party dependencies (like jQuery or React).

Give it a try and I hope to get a star from you!

If someone want's to contribute it would be great!

Rails SQL Views made easy ;)

Igor Kasyanchuk — Tue, 15 Feb 2022 16:58:01 +0000

Hello Rails devs,

I've a new gem:

https://github.com/igorkasyanchuk/sql_view

To skip long sentences just check the demo below:

How to use:

rails g sql_view:view ActiveUsers 'User.confirmed.where(active: true)' --materialized
rails g sql_view:view DeletedProject 'Project.only_deleted'
Create a SQL view from AR relation (or plain SQL).

This is an easier alternative to scenic gem which is wonderful, but as for me requires more steps to add support of rails view into your project.

PS: production-ready, at least on my projects it works, so far so good ;)

Group with ranges for ActiveRecord

Igor Kasyanchuk — Sun, 06 Feb 2022 19:00:41 +0000

If you need to query your Active Record model and group by ranges or multiple values for a specific field - you can try my own gem:

https://github.com/igorkasyanchuk/calculate_in_group

Let's say you have task to count how many Users you have who have 1-5, 5-10, 10+ projects. Solution is simple:

User.calculate_in_group :count, :projects_count, [ 0, 1..5, 5..10, 10..100, 100.. ]
# => {"0"=>555, "1..5"=>145, "10..100"=>3991, "100.."=>190, "5..10"=>2824}

More Examples:

# Grouping can be used with :count, :average, :sum, :maximum, :minimum.

# Group with Ranges
User.calculate_in_group(:count, :age, [...10, 10...50, 50..] # => {"...10"=>1, "10...50"=>3, "50.."=>3}
User.calculate_in_group(:count, :created_at, { "old" => 12.hours.ago..1.minutes.ago, "new" => Time.now..10.hours.from_now }) # => {"old" => 2, "new" => 1}
User.calculate_in_group :count, :projects_count, [ 0, 1..5, 5..10, 10..100, 100.. ] # => {"0"=>555, "1..5"=>145, "10..100"=>3991, "100.."=>190, "5..10"=>2824} 

# Group with arrays or just values
User.calculate_in_group(:count, :role, "with_permissions" => ["admin", "moderator"], "no_permissions" => "user") # => {"with_permissions" => 3, "no_permissions" => 3}

# Other agg functions
User.calculate_in_group(:average, :age, "young" => 0..25, "old" => 60..100) # => {"young" => 11.0, "old" => 80.0}
User.calculate_in_group(:average, :age, "young" => 0..25, "old" => 60...100) # => {"young" => 11.0, "old" => 60.0}
User.calculate_in_group(:maximum, :age, "young" => 0..25, "old" => 60..100) # => {"young" => 20, "old" => 100}
User.calculate_in_group(:minimum, :age, "young" => 0..25, "old" => 60..100) # => {"young" => 3, "old" => 60}
User.calculate_in_group(:sum, :age, "young" => 0..25, "old" => 60..100) # => {"young" => 33, "old" => 160}
User.calculate_in_group(:sum, :age, {"young" => 0..25, "old" => 60..100}) # => {"young" => 33, "old" => 160}

# You can specify "other values" (with custom label) which are out of ranges
User.calculate_in_group(:count, :age, {"young" => 10, "average" => 25, "old" => 60}, {include_nil: "OTHER"}) # => {"young" => 1, "old" => 1, "OTHER" => 7}

# You can specify default value for keys which are missing in query
User.calculate_in_group(:count, :age, {"young" => 10, "average" => 25, "old" => 60}, { default_for_missing: 0 }) # => {"young" => 1, "old" => 1, "average" => 0}

Look forward hearing your feedback :)

Create google-like avatars in your app

Igor Kasyanchuk — Thu, 01 Jul 2021 19:04:30 +0000

For people who just want to check gem and not ready the story: https://github.com/igorkasyanchuk/avatarro

On many projects in my carrier I was needed to handle situation when I need to show some "avatar" image for user when he is missing photo. Usually with gems like paperclip, carrierwave you creating a fallback and it returns a dummy photo.

More interesting solution is to show initials of the user in some circle or rectangle like Google (and many others) doing it.

First solution what we used is custom html/css and very simple helper. This solution is currently on one my project.

But just today I've created a new gem to handle this much better: https://github.com/igorkasyanchuk/avatarro.

Now I can use methods from the gem:

  <%= image_tag Avatarro.image(current_user.full_name), size: '24x24' %>
  <%= image_tag Avatarro.image("Igor Kasyanchuk", solid: true), size: '24x24' %>
  <%= image_tag Avatarro.image("IK"), size: '32x32' %>
  <%= raw Avatarro.svg("IK") %>
  <%= image_tag Avatarro.image(current_user.full_name, random: true, solid: true), size: '20x20', style: 'margin-right: 5px; border-radius: 50%' %>

And get nice images with user initials inside. Since image is an SVG image it will look nice on any screen.

PS: main logic is located here: https://github.com/igorkasyanchuk/avatarro/blob/main/lib/avatarro.rb#L49.

Look forward to hear your comments.

Travel in time in development/staging/... in your Rails app

Igor Kasyanchuk — Mon, 18 Jan 2021 11:22:36 +0000

Hello,

I would like to share my new gem which myself and my QA team already found useful and maybe your team could find too.

https://github.com/igorkasyanchuk/rails_time_travel

The idea is very simple - sometimes you need to add data in the past, and overide Time.now.

I believe you already familiar with the gem https://github.com/travisjeffery/timecop which is very useful for testing.

And my gem is basically providing a simple UI to "control" current time (per user).

module RailsTimeTravel
  module Controller
    extend ActiveSupport::Concern

    included do
      around_action :time_travel_for_request
    end

    def time_travel_for_request
      time_travel
      yield
      time_travel_return
    end

    def time_travel
      if session[:timecop_date]
        logger.info "TIME TRAVEL START: #{session[:timecop_date]}"
        Timecop.travel(session[:timecop_date])
      else
        Timecop.return
      end
    end

    def time_travel_return
      logger.info 'TIME TRAVEL RETURN'
      Timecop.return
    end
  end
end

Most of the logic is simple and was taken from the stackoverflow, and only a simple control panel was codded to change datetime.

To use this gem just add it to the Gemfile, bundle install and start the app. During start is adding ruby module above to the ApplicationController so this code will be executed on every request.

Once a server is running just open /rails/time_travel.

I hope you'll find it useful too!

How to know always about how fast is your code in Rails console?

Igor Kasyanchuk — Mon, 01 Jun 2020 20:27:24 +0000

First, please check this demo of my gem below:

and the link to the gem: https://github.com/igorkasyanchuk/execution_time

It's basically checking total execution time, Active Record spent time and Allocations. Very similar to what you see in logs during regular RoR requests in the logs.

So, no more code like

t0 = Time.now
# code
puts Time.now - t0

This gems works with both IRB and Pry consoles.

The 99% of code is located in one file, and you can see a good example of usage "prepend" method.

module ExecutionTime
  class AppMetrics
    @@counter = 0

    cattr_reader :counter

    def self.reset
      @@counter = 0
    end

    def call(event_name, started, finished, event_id, payload)
      @@counter += 1
    end
  # def red; colorize(self, "\e[1m\e[31m"); end
  # def green; colorize(self, "\e[1m\e[32m"); end
  # def dark_green; colorize(self, "\e[32m"); end
  # def yellow; colorize(self, "\e[1m\e[33m"); end
  # def blue; colorize(self, "\e[1m\e[34m"); end
  # def dark_blue; colorize(self, "\e[34m"); end
    # def colorize(text, color_code)  "#{color_code}#{text}\e[0m" end
    def AppMetrics.with_color(text)
      "\e[1m\e[32m[METRICS]\e[0m  \e[32m#{text}\e[0m"
    end
  end

  ActiveSupport::Notifications.subscribe(
    "sql.active_record",
    ExecutionTime::AppMetrics.new
  )

  class Measurer
    def Measurer.watch
      AppMetrics.reset

      start     = Time.now
      before    = GC.stat(:total_allocated_objects)
      ActiveRecord::LogSubscriber.reset_runtime

      result   = yield

      after    = GC.stat(:total_allocated_objects)
      duration = (Time.now - start)
      db_after = ActiveRecord::LogSubscriber.reset_runtime

      info = "Completed in #{(duration * 1000).round(1)}ms | Allocations: #{after - before}"

      if AppMetrics.counter > 0
        info << " | ActiveRecord: #{db_after.round(1)}ms"
        info << " (queries: #{AppMetrics.counter})"
      end

      puts AppMetrics.with_color(info)
      result
    end
  end

  module IrbContextExt
    def evaluate(*args)
      Measurer.watch do
        super(*args)
      end
    end
  end

  module BindingExt
    def eval(*args)
      if args == ['self'] || args == ['']
        super(*args)
      else
        Measurer.watch do
          super(*args)
        end
      end
    end
  end

  module PryExt
    def evaluate_ruby(code)
      current_binding.class.send :prepend, BindingExt
      super(code)
    end
  end
end

Code above could also tell you more about:

blocks
"inheritence" using prepend and super
passing unknown arguments further using *args
Rails ActiveSupport::Notifications (internal) + subscription
simple usage of GC stats (code examples I took from Rails sources)
colorized string output :)

PS: Gem was created maybe in 1.5 hour, and most of the time I spent on inspecting source code of Rails and Pry gems. But it shows that even in a such short amount of time it's possible to create useful tools.

How to create own utility methods for your Rails application

Igor Kasyanchuk — Wed, 19 Feb 2020 15:33:43 +0000

Hello,

As a developer, I need from time to time to quickly execute SQL, or check something in DB, truncate a table, etc when I'm in the rails console.

You may already know about using ActiveRecord::Base.connection.execute("SQL query") solution, but I must admit I'm a lazy developer when it comes to doing routine tasks or things where I need to type long pieces of code. And actually a snippet of code above is not everything that you need to type, you may also need to add .to_a to see the result of the query.

I know the following rule:

laziness is the engine of progress!

So, I tried to solve my issue as a developer and create an open-source solution to use it from project to project: https://github.com/igorkasyanchuk/execute_sql

This is a demo of how it works:

I'll explain how it works.

Step of creation gem I'll skip, but basically you need to create a new gem (rails plugin new <name>).

Now we need to understand how to add our own method just in the rails console.

module ExecuteSql
  class Railtie < ::Rails::Railtie

    console do
      TOPLEVEL_BINDING.eval('self').extend ExecuteSql::ConsoleMethods
    end

  end
end

This is a piece of code from my gem. You can see that Rails provides a helper method console where you can pass the code which will be executed when you starting rails c.
In our case this is TOPLEVEL_BINDING.eval('self').extend ExecuteSql::ConsoleMethods.

In case you have wondered, what this top-level constant TOPLEVEL_BINDING is all about better to check sample of usage below:

a = 42
p binding.local_variable_defined?(:a) # => true
p TOPLEVEL_BINDING.local_variable_defined?(:a) # => true

def example_method
  p binding.local_variable_defined?(:a) # => false
  p TOPLEVEL_BINDING.local_variable_defined?(:a) # => true
end

example_method

More details about TOPLEVEL_BINDING you can find here.

[11] pry(main)> TOPLEVEL_BINDING.eval('self')
=> main
[12] pry(main)> TOPLEVEL_BINDING
=> #<Binding:0x0000000001350b00>

As you can see TOPLEVEL_BINDING.eval('self') is basically the context of our console app.

So the last thing for us to do is to extend the main app with our class methods from ExecuteSql::ConsoleMethods module, source code is here.

This module inside is responsible for queries DB, and basically I took most of the code from my other gem rails_db and printing results using terminal-table gem.

Now my life is easier :)

And I hope you can implement your own utility methods.

The fastest way to prototype API in Rails application

Igor Kasyanchuk — Thu, 13 Feb 2020 20:14:25 +0000

Hello, Ruby community,

https://github.com/igorkasyanchuk/fake_api

I've for a review one gem which could help you to build prototype (or production-ready) API in your Rails application.

Very often if you are just backend developer you need to implement some skeleton of API for Frontend Team. Most of the time you need to quickly change response, change format, rename something and have data that looks real.

When we are writing unit tests we often using Faker gem and FactoryBot to get nice sets of data and close to "real" user names, emails, etc.

So the idea of this gem is to use Faker to help you to build API prototype quickly and use syntax similar to Rails routing and FactoryBot to define API routes and responses.

Just check the demo and give a chance to this gem.

PS: You are also welcome to contribute :)

Monitor Rails performance in real-time and for free

Igor Kasyanchuk — Tue, 11 Feb 2020 21:44:29 +0000

https://github.com/igorkasyanchuk/rails_performance

I've created a new gem to monitor the performance of RoR apps.
It's using Redis to store data. All are stored locally and not sent to 3rd party services.

Look forward to hearing your feedback.