Ruby basics

• Install Ruby
• Setup gems
• gem install nokogiri
• gem install builder
• Database: SQLite (docs)
• Database driver:
• ! gem install dbi (docs don't work, but these docs do)
• ! gem install dbd-sqlite3

• ? gem install sqlite-ruby (docs)

• Write script offline
• Host on Heroku

Save URL to a file

require 'open-uri'
open('image.png', 'wb') do |file|
    file << open('http://example.com/image.png').read
end

is this the same as:

require 'open-uri'
file = open('image.png', 'wb')
file << open('http://example.com/image.png').read

Fetch URL through a proxy

print Net::HTTP::Proxy(proxy_addr, proxy_port, proxy_user, proxy_pass).get URI.parse('http://www.compufer.com/')

Hello world

puts "Hello, what's your name?"
STDOUT.flush
name = gets.chomp
puts 'Hello, ' + name + '.'

Blocks

def try  

  if block_given?  

    yield  

  else  

    puts "no block"  

  end  

end  

try # => "no block"  

try { puts "hello" } # => "hello"  

try do puts "hello" end # => "hello" 

Notes

• Whichever variables(s) you pass into the block, the method will fill them with something, depending on what its function is. e.g. "open" puts a file handle in there.
• List of file modes
• Hash, Hashes
• ---------------
• Builder tut1, tut2, tut3

• Read docs
• open-uri docs
• open returns an IO like object
• File
• Ruby blocks (closures)