EJ ej2015

In an earlier video we took a look at Rack to build incredibly lightweight web applications with Ruby. Rack's toolkit allowed us to quickly throw to get a working application, but we did have to put a little effort into it once we wanted to build something a little more complex.

Sometimes you want a fast and simple framework for building a simple web application. Perhaps you only need to respond to a handful of routes, or you want the response time for a small part of a bigger application to be lighting fast. The Sinatra framework is made for just these moments.

Today let's take a quick look at this framework and see how quickly we can build lightweight web applications.

To get started we first need to install the Sinatra gem:

gem install sinatra

Apache Kafka is a highly-scalable publish-subscribe messaging system that can serve as the data backbone in distributed applications. With Kafka’s Producer-Consumer model it becomes easy to implement multiple data consumers that do live monitoring as well persistent data storage for later analysis. You can assume that RabbitMQ is similar to Kafka, You do get an option for message-sending or Broadcasting. The installation process for OSX is as below.

The best way to install the latest version of the Kafka server on OS X and to keep it up to date is via Homebrew.
```
 brew search kafka
 brew install kafka 
```
The above commands will install a dependency called zookeeper which is required to run kafka. Start the zookeeper service.

zkserver start

Common Options

-#, --progress-bar Make curl display a simple progress bar instead of the more informational standard meter.

-b, --cookie <name=data> Supply cookie with request. If no =, then specifies the cookie file to use (see -c).

-c, --cookie-jar <file name> File to save response cookies to.

I'm a fan of MiniTest::Spec. It strikes a nice balance between the simplicity of TestUnit and the readable syntax of RSpec. When I first switched from RSpec to MiniTest::Spec, one thing I was worried I would miss was the ability to add matchers. (A note in terminology: "matchers" in MiniTest::Spec refer to something completely different than "matchers" in RSpec. I won't get into it, but from now on, let's use the proper term: "expectations").

Understanding MiniTest::Expectations

Let's take a look in the code (I'm specifically referring to the gem, not the standard library that's built into Ruby 1.9):

# minitest/spec.rb

module MiniTest::Expectations

	//https://play.golang.org/p/9deaMVBwBgm

	package main

	import (
	"fmt"
	"encoding/json"
	)

	type BodyRequest struct {

	Rails cache SQL calls

	So suppose we have a model Author which has_many Book

	expect(author.books).to equal author.books

	If Book has a scope, say by_countries:

	scope :by_countries, -> c { where(countries: c) if c.present? }

	# encoding: UTF-8
	# Place in config/deploy.rb
	# See: https://gist.github.com/joost/9343156
	# Adapted to work with rbenv
	namespace :rails do
	desc "Open the rails console on primary app server"
	task :console do
	on roles(:app), primary: true do
	rails_env = fetch(:stage)
	execute_interactively "#{bundle_cmd} #{current_path}/script/rails console #{rails_env}"


	set nocompatible " be iMproved
	filetype off " required!

	set rtp+=~/.vim/bundle/vundle/
	call vundle#rc()

	" let Vundle manage Vundle
	" required!
	Bundle 'gmarik/vundle'

	#given files a.rb and b.rb in the same directory

	#b.rb
	dir = File.expand_path('.',__dir__)
	# $: is a short form for $LOAD_PATH
	$:.unshift(dir) unless $:.include?(dir)
	require 'a'

	## now we can run b.rb from anywhere and it will require a.rb successfully.