Download Files with Ruby

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This weekend, I remembered an old podcast I used to listen to that I wanted to hear again. It wasn't available on iTunes anymore, so I did a Google search for it. I found the show's Web site, and saw that they had a complete archive of all four seasons of the podcast (20 episodes per season). The problem was, each episode was on it's own page, with a separate page to access the download link. I started to manually try to download each episode, but that got old REALLY quickly. Why not write a simple script to do the work for me?

Here's the Ruby script I whipped up in about 15 minutes:

require 'net/http'

1.upto(4) do |season|
  1.upto(20) do |episode|
    episode = '%02d' % episode
    puts "Downloading Season ##{season}, Episode ##{episode}"
    Net::HTTP.start("website.com") do |http|
      resp = http.get("/episode_archive/s#{season}ep#{episode}.mp3")
      open("s#{season}ep#{episode}.mp3", "w") do |file|
        file.write(resp.body)
      end
    end
    puts "Episode downloaded!"
    puts
  end
end

puts "All files downloaded!!"

An explanation of what's going on here:

Lines #3-4: There are 4 seasons and 20 episodes per season, so iterate through them.
Line #5: We need to left pad the episode numbers, because that's how the files are named.
Line #7: Connect to the host.
Line #8: Get the episode (named like "s1ep05.mp3").
Lines #9-11: Save the file using the same name.

Tagged: ruby, script

BarCamp Nashville 09 Presentation - Symfony vs Rails

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Brent Shaffer and I gave a presentation at the 2009 Nashville BarCamp titled "Test Your Might - Framework Combat" comparing Ruby/Rails with PHP/Symfony. Below is a copy of the slides we presented.

Tagged: symfony, php, rails, ruby, presentation, barcamp

Ruby Script to Add Apache Virtual Host Entry

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When you're working with Rails, you never really have to add a virtual host entry for development (unless you use Passenger). You can always just fire up script/server and navigate to http://localhost:3000.

At my new job, I'm doing a lot of work on PHP and Drupal sites, which require you to add an entry to your host file and add a virtual host conf file for Apache. After only going through this process twice, I was already tired of it. I wrote the following script to automate the process for me.

#!/usr/bin/ruby

########################################
##### VARIABLES YOU NEED TO CHANGE #####
########################################

host_dir  = '/etc/hosts'            # path to your hosts file
sites_dir = '/Library/Webserver'    # path to the directory where you keep your sites (NO TRAILING SLASH!!!)
conf_dir  = '/etc/apache2/sites'    # path to directory where named conf files live

########################################

unless ARGV[0]
  puts "Usage: add_site sitename [hostname_for_url]"
  puts "Example: add_site sample sample.dev"
  exit
end

name = ARGV[0].strip
hostname = ARGV[1].nil? ? ARGV[0] : ARGV[1].strip

# first things first: make sure named conf file doesn't exist already
if File.exists?("#{conf_dir}/#{name}.conf")
  puts "Conf file named #{name}.conf already exists!"
  exit
end

# check to make sure host file exists
if File.exists?(host_dir)
  
  puts "Adding entry to #{host_dir}."
  File.open(host_dir, 'a') do |host_file|
    # append host entry to end of file
    host_file.puts "127.0.0.1\t#{hostname}"
  end
  puts "Host entry added!"
  
  puts "Adding named conf file."
  File.open("#{conf_dir}/#{name}.conf", 'a') do |host_file|
    # add entry
    host_file.puts <<EOF
<VirtualHost *:80>
  ServerName #{hostname}

  DocumentRoot "#{sites_dir}/#{name}"
	DirectoryIndex index.php
	<Directory "#{sites_dir}/#{name}">
		Options FollowSymLinks MultiViews Includes
		AllowOverride All
		Order allow,deny
		Allow from all
	</Directory>
</VirtualHost>
EOF
  end
  puts "Conf entry added!\n"
  
  puts "Restarting apache.\n"
  system "apachectl graceful"
  puts "Done!"
  
end

What you need to do to get this to work:

1. Change the variables at the top of the file (path to your hosts file, path to the folder where you keep your development site, and path to the directory where you want to keep your named conf files).
2. Rename the file to add_site(with no extension) and move to your /usr/bin directory.
3. Chmod the file to be executable.

Now you can run the add_site command and provide it with the name of the site folder and optionally the name of the local domain you'd like to use.

Tagged: ruby, script, apache

Twitter Gem Examples

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I recently set up a Twitter account for a monthly bill and task tracking application that I built a few months back. My intent was to try and drive traffic to my site (which had been sitting unused by the general public). To do this, I decided to mass-follow around 350 accounts in hopes of having them follow me back and checking out the site. It worked pretty well, and I even had quite a few users cold follow the account. At first, I would follow the users that followed me when I got the notification from Twitter. After a few days, I got a little behind and the followers started to build up. I figured this would be a good time to check out the Twitter gem to see if I could automate some of my tasks. The gem had exactly what I needed: a way to talk to Twitter via Ruby. I've included below two of the tasks that I created to work with my Twitter account.

First things first, I needed to set up my authentication. To do this, I just created a YAML file in my home directory called .twitter that contains my user email and password. The . means that it's a hidden file (I'm on a Mac). The YAML file is extremely simple, and looks like this:

email: my_twitter_email
password: my_twitter_password

Now, I could use this YAML file for any of the scripts that I wrote.

Task #1: Follow Users Who Follow Me

I wanted to get a list of all my followers and check to see if I'm already following them. If I'm not, I want to create a friendship with them.

#!/usr/bin/env ruby
require 'rubygems'
require 'twitter'

config = YAML::load(open("#{ENV['HOME']}/.twitter"))

httpauth = Twitter::HTTPAuth.new(config['email'], config['password'])
base = Twitter::Base.new(httpauth)

base.followers.each do |follower|
  if !follower.following
    # make sure to rescue in case there is anything wrong with the account
    base.friendship_create(follower.id, true) rescue next
    puts "Created friendship with #{follower.screen_name}"
  end
end

Task #2: Stop Following Users Who Aren't Following Me

I followed about 350 accounts initially, and after about a week, I figured that if they weren't following me by then, they'd probably never follow me. So, since I'm all about reciprocation, I decided to stop following them.

#!/usr/bin/env ruby
require 'rubygems'
require 'twitter'

config = YAML::load(open("#{ENV['HOME']}/.twitter"))

httpauth = Twitter::HTTPAuth.new(config['email'], config['password'])
base = Twitter::Base.new(httpauth)

base.friends.each do |friend|
  if !base.friendship_exists?(friend.screen_name, 'listode')
    base.friendship_destroy(friend.id)
    puts "Destroyed friendship with #{friend.screen_name}"
  end
end

A Quick Note

Keep in mind that, unless you've been white-listed, your account is limited to 100 API calls per hour. That shouldn't be an issue with the first script, since it only makes one call to get the list and one call for each friend creation. You should stay below the cap (unless you have more than 100 followers who you aren't following).

The second script is a different story. It makes one call to get the list of friends, one call for each friend to check following, and one call to destroy the friendship if they aren't following. This can easily burn up the API limit if you have more than 100 friends. I haven't figured out a way to reduce the number of API calls for that script. If you have any tips, leave them in the comments.

Tagged: twitter, tutorial, ruby

Ruby Net::FTP Tutorial

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Recently, at Plexus, a client needed the ability to import photos to their site from a remote FTP server. Perfect opportunity for me to learn about Net::FTP. Turns out it was surprisingly simple.

Let's say we want to login to the server 'ftp.sample.com' with the username 'test' and the password 'pass', then switch to the directory 'source/files' and get the file 'photos.zip'. There are a couple ways to do this. First, we have to create and FTP connection with:

# Login to the FTP server
ftp = Net::FTP.new('ftp.sample.com', 'test', 'pass')
# OR
ftp = Net::FTP.new('ftp.sample.com')
ftp.login('test', 'pass')

# Switch to the desired directory
ftp.chdir('source/files')

# Get the file we need and save it to our 'ftp_photos' directory
ftp.getbinaryfile('photos_2009-03-29.zip', 'ftp_photos/photos.zip')

# We're done, so we need to close the connection
ftp.close

You can also accomplish the same thing by passing a block to the open method, like so:

Net::FTP.open('ftp.sample.com') do |ftp|
  ftp.login('test', 'pass')
  ftp.chdir('source/files')
  ftp.getbinaryfile('photos_2009-03-29.zip', 'ftp_photos/photos.zip')
end

Pretty straightforward and simple.

Tagged: ruby, ftp, tutorial, net ftp