group :development, :test do
  gem "jasmine"
end

bundle install

rails generate jasmine:install

Run tests

1. In your browser
2. Continuous Integration Mode (CI)

Browser Mode

rake jasmine

http://localhost:8888/

rails generate jasmine:examples

Configurable Settings

Raise Exceptions

Stop Spec on Expectation Failure

Run Tests in Random Order

Continous Integration Mode

rake jasmine:ci

Jasmine.configure do |config|
   config.ci_port = 1234
end

Configuration

• jasmine.yml
• jasmine_helper.rb

Sample configuration:

# spec/javascripts/support/jasmine.yml
random: true
show_console_log: false
stop_spec_on_expectation_failure: true

# spec/javascripts/support/jasmine_helper.rb
Jasmine.configure do |config|
  config.random = false
  config.show_console_log = false
  config.stop_spec_on_expectation_failure: false
  config.show_full_stack_trace = false
  config.prevent_phantom_js_auto_install = false
end

Testing

Testing JavaScript

Plugins worth considering

• Jasmine-Jquery – this plugin provides a lot of jquery related matchers. Download it here
• Jasmine-Matchers – a tool to provide additional matchers. Download it here
• Jasmine-Fixture – a plugin that provides DOM creation using CSS selectors, therefore you can interact with the DOM much easier. Download it here

Write Beautiful Unit tests

Importance of Test Discipline

• Writing tests first gives you a clearer perspective on the ideal API design.
• Does the developer understand the problem enough to articulate in code all critical component requirements?
• Manual QA is error-prone. In my experience, it’s impossible for a developer to remember all features that need testing after making a change to refactor, add new features, or remove features.
• Continous Integration prevents failed builds from getting deployed to production.

Bug Report vs plain Unit Test

• What are you trying to test?
• What should it do?
• What is the real-time output (actual behavior)?
• What is the expected output (expected behavior)?

describe("CalculatorAddMethod", function() {
  var calculator = new Calculator();
  it("should return number", function() {
    const actual = typeof Calculator.add(5,10);
    const expected = 'number'
    expect(actual).toEqual(expected);
  });
});

• What are you trying to test?
  • -> Go for the test description. It is testing for the return type of the add method of Calculator().
• What should it do?
  • -> Again, look at the test description. It clearly says that it is testing for the return type of add method.
• What is the actual output?
  • -> There is a dedicated variable which holds the actual result and how you got the actual result. TWO FOR ONE!
• What is the expected output?
  • -> Again, there is a dedicated variable which holds the actual result. Straight as a ruler!

Make your tests even better

Easter Egg

Conclusion

• What are you trying to test?
• What should it do?
• What is the real-time output (actual behavior)?
• What is the expected output (expected behavior)?
• How can be the test reproduced?

Screenshots with PhantomJS

gem install phantomjs

var instance = require('webpage').create();

instance.open('http://redpanthers.co/', function() {
instance.render('screenshot-phantom.png');
phantom.exit();
});

phantomjs filename.js

Screencap gem

gem install phantomjs -v 1.9.8

phantomjs --version

gem 'screencap'

gem install screencap

Usage

require 'screencap'
screenshot = Screencap::Fetcher.new(<url>)
image = screenshot.fetch

• Fetcher class accepts url of the website to take screenshot.
• Screenshot is taken when fetch method is called.
• Also, fetch method supports various optional parameters to specify the area to capture the screenshot.
• We can specify where to store the screenshot captured, as shown below.

image = obj.fetch(
 output: '~/folder/file-name.png',
 # dimensions for taking screenshot of specific area
  width: 1024,
 height: 768
 )

Example

require 'screencap'
screenshot = Screencap::Fetcher.new('http://redpanthers.co/')
image = screenshot.fetch(output: '~/screencap/screencap.png',
                                   width: 300,
                                  height: 500)

Webshot gem

gem 'webshot'

gem install webshot

Usage

require 'webshot'
screenshot = Webshot::Screenshot.instance
screenshot.capture "https://github.com/", "image.png", width: 1024, height: 800

References

• PhantomJS
• Screencap gem
• Webshot gem

• If the request matches any safelist, it is allowed.
• If the request matches any blocklist, it is blocked.
• If the request matches any throttle, a counter is incremented in the Rack::Attack.cache. If any throttle’s limit is exceeded, the request is blocked.
• Otherwise, all tracks are checked, and the request is allowed.

Implementation

gem 'rack-attack'

# In config/application.rb
config.middleware.use Rack::Attack

# In config.ru
use Rack::Attack

class Rack::Attack
  Rack::Attack.cache.store = ActiveSupport::Cache::MemoryStore.new
  ########
end

Throttle

throttle('api/ip', limit: 3, period: 10) do |req|
  req.ip
end

Safelist

Rack::Attack.safelist('allow from localhost') do |req|
  '127.0.0.1' == req.ip
end

Blacklist

Rack::Attack.blacklist('block 2.2.2.2') do |req|
  '2.2.2.2' == req.ip
end

Fail2Ban: Fail2Ban.filter can be used within a blocklist to block all requests from misbehaving clients. Allow2Ban: Allow2Ban.filter works the same way as the Fail2Ban.filter except that it allows requests from misbehaving clients until such time as they reach maximum retry.

Block logins from a bad user agent

Rack::Attack.blacklist('block bad UA logins') do |req|
  req.path == '/login' && req.post? && req.user_agent == 'BadUA'
end

Tracks

Rack::Attack.track("special_agent") do |req|
  req.user_agent == "SpecialAgent"
end

Security issues that Rack Attack addresses

• Rate limits against DDoS and abusive users

DDoS is short for Distributed Denial of Service. It uses multiple computers and Internet connections to flood the targeted resource.

Whitelist Search Engine spiders

        Though we blacklist IP’s that are misbehaving, we have to whitelist search engine spiders. But they have a huge range of IP’s. So we can check user agent. But it’s something anyone can fake. We can run a reverse DNS lookup of the accessing IP and perform a forward DNS lookup on the domain (using host command). Verify that it is same as the original IP address from the logs.

References

• https://www.diycode.cc/projects/kickstarter/rack-attack
• https://searchcode.com/file/86455896/README.md
• http://sourcey.com/building-the-prefect-rails-5-api-only-app/

<%= line_chart data, adapter: "google" %> <!-- or highcharts -->

<%= line_chart User.group_by_day(:created_at).count %>

In the above example, I have just shown you how we can make a line chart.Similarly, you can create Pie chart, Column chart, Bar chart, Area chart, Scatter chart, Geo charts, Timeline(Google Charts)etc. All you need is that one line of Ruby code. Cool, isn’t it!!

class ViewsController < ApplicationController
  def show
    @view = View.all
  end
  def views_by_day
    render json: View.group_by_day(:viewed_at, format: "%B %d, %Y").count
  end
end

<div class="container">
  <h3>Views By Day</h3>
  <%= line_chart views_by_day_view_path %>
</div>

<%= line_chart @.map { |view|
 {name: view.name, data: view.feats.group_by_week(:created_at).count}
} %>

<%= line_chart Feat.view(:view_id).group_by_week(:created_at).count %>

References

• http://chartkick.com/
• https://ankane.github.io/chartkick.js/examples/

• Storing data in JSON and JSONB format
• Generating JSON results from the query itself

Getting Started

How to generate JSON

select row_to_json(users) from users where id = 1;

{"id":1,"email":"hsps@redpanthers.co","encrypted_password":"iwillbecrazytodisplaythat",
"reset_password_token":null,"reset_password_sent_at":null,
"remember_created_at":"2016-11-06T08:39:47.983222",
"sign_in_count":11,"current_sign_in_at":"2016-11-18T11:47:01.946542",
"last_sign_in_at":"2016-11-16T20:46:31.110257",
"current_sign_in_ip":"::1","last_sign_in_ip":"::1",
"created_at":"2016-11-06T08:38:46.193417",
"updated_at":"2016-11-18T11:47:01.956152",
"first_name":"Super","last_name":"Admin","role":3}

select row_to_json(results)
from (
  select id, email from users
) as results

{"id":1,"email":"hsps@redpanthers.co"}

select row_to_json(result)
from (
  select id, email,
    (
      select array_to_json(array_agg(row_to_json(user_projects)))
      from (
        select id, name
        from projects
        where user_id=users.id
        order by created_at asc
      ) user_projects
    ) as projects
  from users
  where id = 1
) result

{"id":1,"email":"hsps@redpanthers.co", "project":["id": 3, "name": "CSnipp"]}

array_to_json(array_agg(row_to_json(user_projects)))

json_agg(user_projects)

json_build_object('foo',1,'bar',2)

{"foo": 1, "bar": 2}

References

[].each
[1, 3, 4].each
file.each
{}.each

fib = Enumerator.new do |y|
  a = b = 1
  loop do
    y << a
    a, b = b, a + b
  end
end

[1,2,3].map { |i| i*i }

foo.map { |i| i * * }

foo.lazy.map { |i| i * i }

fille = File.open('OurHugeFile.log')

file.each_line.lazy.take(3).to_a

 file.each_line.lazy.select { |line| line.match(/INFO/) }.first(2)

file.each_line.lazy.each_with_index.map { |l, i| "#{i}: #{l}" }.select { |i| match(/INFO/) }.first(3)

CREATE INDEX index_name
ON prices (user_id);

add_index :prices, :user_id

CREATE INDEX index_name
ON user_views (user_id, article_id);

add_index :user_views, [:user_id, :article_id]

scope :articles, where(:spam => 'true')

CREATE INDEX index_name
on articles (spam is true);

add_index :articles, :spam, name: "index_articles_on_spam", where: "(spam IS true)"

DROP INDEX index_name;

remove_index :books, :created_at

• Index Primary key
• Index Foreign key
• Index all columns you would be passing into where clause
• Index the keys used to Join tables
• Index the date column (if you are going to call it frequent, like rankings of a particular date)
• Index the type column in an STI or polymorphism.
• Add partial index to scopes
• Do not index tables with a lot of read, write
• Do not index tables you know that will remain small, all through out its life time
• Do not index columns where you will be manipulating lot of its values.

# app/controllers/application_controller.rb
around_action :set_time_zone, if: :current_user
private
def set_time_zone(&block)
  Time.use_zone(current_user.time_zone)
end

config.time_zone = 'Central Time (US & Canada)'

• System timezone
• Database timezone
• Rails applications own timezone

  * Time.now
  * Date.today
  * Date.today.to_time
  * Time.parse("2015-07-04 17:05:37")
  * Time.strptime(string, "%Y-%m-%dT%H:%M:%S%z")

* Time.current
* 2.hours.ago
* Time.zone.today
* Date.current
* 1.day.from_now
* Time.zone.parse("2015-07-04 17:05:37")
* Time.strptime(string, "%Y-%m-%dT%H:%M:%S%z").in_time_zone

after_create Is called after Base.save on new objects that haven‘t been saved yet (no record exists) after_save Is called after Base.save (regardless of whether it‘s a create or update save) after_commit Is called after the database transaction is completed.

User.transaction do
    # update company
    # update hr_department
    # update user_table
end

Q) How to learn Ruby on Rails?

Q) Is it required to know Ruby before you learn rails?

NO

Q) How can I learn Ruby?

1. http://rubymonk.com/
2. http://tryruby.org/
3. http://rubykoans.com/

 Q) How long will it take to learn Ruby/Ruby on Rails?

PS: this is just my list, if you know some good online resources. Please do add them as comments, it would help those who are starting out with Ruby and Rails. Also sorry for any typo or grammatical errors.