check if a webserver is reachable, if not send an email, can be used via cron...

gistfile1.rb

require 'rubygems'
require 'action_mailer'
require 'mechanize'

# Delivery
SENDER_MAIL = "[email protected]"
ActionMailer::Base.delivery_method = :smtp
ActionMailer::Base.smtp_settings = {
  :address => "mail.gmx.de",
  :port => 25,
  :domain => "www.gmx.de",
  :authentication => :login,
  :user_name => "[email protected]",
  :password => "...",
}

# Recipients
MAIL_ADDRESS = ["[email protected]","..."]

# What to look for
URLS_TO_CHECK = [
  "http://www.....de"
]

class Mailer < ActionMailer::Base
  def exception_notification(text)
    content_type "text/plain"
    recipients MAIL_ADDRESS
    from SENDER_MAIL
    subject "Warning"
    body :text => text   
  end
end
Mailer.template_root = File.dirname(__FILE__)

exception = ""
URLS_TO_CHECK.each do |url|
  begin 
    a = Mechanize.new.get(url)
  rescue
    exception += "Can not reach #{url}. #{$!.inspect}\n"
  end
end
if exception != ""
  Mailer.deliver_exception_notification(exception)
end

Thanks, I wrote a nifty server-side script for periodic status mails based on your code: https://github.com/dmke/cronmail

(Besides, I erased the deprecation warnings you'll get, if you are using actionmailer >= 3.0.0)