Ruby Script to Add Apache Virtual Host Entry

Aug 10, 2009  -  Comments

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.



host_dir  = '/etc/hosts/index.html'            # path to your hosts file
sites_dir = '/Library/Webserver/index.html'    # path to the directory where you keep your sites (NO TRAILING SLASH!!!)
conf_dir  = '/etc/apache2/sites/index.html'    # 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"

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!"

# 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 "\t#{hostname}"
  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
  puts "Conf entry added!\n"
  puts "Restarting apache.\n"
  system "apachectl graceful"
  puts "Done!"

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: rubyscriptapache

Rails DELETE requests with JQuery

May 20, 2009  -  Comments

When I write admin controls for for a Rails app, I like to make the delete links just fire off an Ajax request, delete the record, and remove the element from the page. This is easy with the Rails default setup using Prototype. All you have to do is use link_to_remote with a :method => 'delete' to make Rails do all the work. The problem is, this is the code that Rails generates:

<%= link_to_remote("Delete", :url => admin_post_path(post), :method => :delete) %>
<!- turns into: -->
<a href="#" onclick="new Ajax.Request('/users/63', {asynchronous:true, evalScripts:true, method:'delete'});); return false;">Delete</a>

While this isn't terrible, it's certainly not very pretty. Surely we can make the code cleaner and simpler!

Well, we've recently switched to using JQuery for all of our new apps at Plexus. Unless you use the JRails plugin, the link_to_remote helper no longer works when using JQuery. I figured this would be a good time to switch the remote calls to be handled separately by JavaScript, instead of spitting out a ton of script in the HTML.

It's easy to just hijack links via JavaScript and have them submit via Ajax, but how do we handle REST requests that require the DELETE method?

I decided to just add a specific class to all links that I wanted to be hijacked by JavaScript, then add the code in my js file to handle the links with Ajax. My DELETE links would look like this:

<!- Link that uses DELETE method -->
<%= link_to 'Delete', entry_path(entry), :class => 'remote-delete' %>

The key to hijacking the link is to include the hidden _method attribute set to 'delete'. My JavaScript to hijack the link would look like this:

$(document).ready(function() {
  $('a.remote-delete').click(function() {
    // we just need to add the key/value pair for the DELETE method
    // as the second argument to the JQuery $.post() call
    $.post(this.href, { _method: 'delete' }, null, "script");
    return false;

This converts every link that has the remote-delete class to an Ajax request with the DELETE method!

Tagged: jquerydeleterest

Twitter Gem Examples

Apr 22, 2009  -  Comments

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}"

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')
    puts "Destroyed friendship with #{friend.screen_name}"

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: twittertutorialruby

Better Text Replacement with CSS

Apr 16, 2009  -  Comments

There are several methods for rendering non-web fonts (eg. Cufón and sIFR). Both are tedious to set up and implement. The easiest alternative is the good old image-instead-of-text trick, but that's not good for SEO, even with alt tags.

There is a way to have SEO text AND use an image as the text. With a little CSS trickery, you can easily achieve the desired effect. Worth noting, however, is that this method is really only good for non-dynamic, fixed width text (such as headings). It's not practical for blocks of text.

The first thing you need is an image for the text you want to replace (and yes, I'm using Comic Sans):

Now for the html code that we'll be working with:

<h1 class="replace heading">My Heading</h1>

The CSS does all the work.

.replace {
.heading {
  padding:26px 0 0 0;
  background:url('/images/custom_header.png') no-repeat 0 0;

First, we make the h1 virtually invisible via CSS by assigning a height and font-size of 0. Then we make sure it's invisible in all browsers by setting the letter-spacing and text-indent. The heading class has a top-padding which creates just enough space to show the image, which we set as the background. Super easy and effective!

You'll notice that I made two classes. I use the replace class as a global for the styles that are common to all replaced text, then the heading class has the unique styles.

Tagged: csstext replacementtutorial

Ruby Net::FTP Tutorial

Mar 29, 2009  -  Comments

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:

require 'net/ftp'

# 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

# 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

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

require 'net/ftp'

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

Pretty straightforward and simple.

Tagged: net ftptutorialftpruby