Ruby Projects and Libraries

Ruby Projects and Libraries Vorleak Chy (vorleak.chy@gmail.com) Software Engineer Yoolk Inc http://groups.google.com/group/khmertech/

Agenda

Projects and Using Code from Other Files

Libraries

RubyGems

Introduction

Using code already written and prepared by other developers within your own applications

Projects and Using Code from Other Files

Basic File Inclusion

Inclusions from Other Directories

Logic and Including Code

Nested Inclusions

Basic File Inclusion

Uses the require or load command to load the external file into the current program

#file: string_extensions.rb class String def vowels self.scan(/[aeiou]/i) end end #file: vowel_test.rb require 'string_extensions' puts "This is a test".vowels.join('-')

Basic File Inclusion (Cont.)

Ruby programmers generally use require rather than load. The effects of load are only useful if the code in the external file has changed or if it contains active code that will be executed immediately

#file: b.rb load 'a' puts "Hello from b.rb" load 'a' puts "Hello again from b.rb" #result output Hello from a.rb Hello from b.rb Hello from a.rb Hello again from b.rb #file: a.rb puts "Hello from a.rb"

Inclusions from Other Directories

The process of require and load

First looks the file in the current folder

Second looks the file in the various folders where Ruby stores its own file and libraries

Lists of directories to search for included files in a special variable called $:.

$:.each { |d| puts d } /usr/local/lib/ruby/site_ruby/1.8 /usr/local/lib/ruby/site_ruby/1.8/i686-darwin8.8.1 /usr/local/lib/ruby/site_ruby ...

Inclusions from Other Directories (Cont.)

Adds extra folders to search the file

$: is an array, so you can push extra items to it

$:.push '/your/directory/here' require 'yourfile'

Logic and Including Code

Adds logic to the require or load command

$debug_mode = 0 require $debug_mode == 0 ? "normal-classes" : "debug-classes" %w{file1 file2 file3 file4 file5}.each { |l| require l }

Nested Inclusions

Code from files that are included into others with require and load has the same freedom as if the code were pasted directly into the original file.

#file: a.rb require 'b' #And b.rb contains the following: require 'c' #And c.rb contains the following: def example puts "Hello!" end #And d.rb contains the following: require 'a' example

Libraries

Collection of routines that can be called by separate programs, but that exist independently of those programs.

A list of all the standard libraries, including documentation, is available at http://www.ruby-doc.org/stdlib/

How to use two standard libraries

net/http Library

HTTP stands for HyperText Transfer Protocol, and it’s the main protocol that makes the World Wide Web work, as it provides the mechanism by which Web pages, files, and other media can be sent between Web servers and clients

require 'net/http' Net::HTTP.get_print('www.rubyinside.com', '/') require 'net/http' url = URI.parse('http://www.rubyinside.com/') response = Net::HTTP.start(url.host, url.port) do |http| http.get(url.path) end content = response.body

OpenStruct Library

More flexible than Struct

Creates data objects without specifying the attributes

Create attributes on the fly

#struct Person = Struct.new(:name, :age) me = Person.new("Fred Bloggs", 25) me.age += 1 #openStruct require 'ostruct' person = OpenStruct.new person.name = "Fred Bloggs" person.age = 25

RubyGems