One of the books which are still in my wishlist is “Patterns of Enterprise Application Architecture”. It is a phenomenal book, or rather catalog, of design patterns specifically for enterprise software, but most of them are universally usable. I first heard about this book when the FLOW3 project started, and now having read the book I find it easier to understand some of the architectural decisions made by the FLOW3 team. Furthermore the FLOW3 framework made it a lot easier to understand a lot of the patterns from the book. since many of them has a implementation in the framework.

The author, Martin Fowler, has published a short overview of each of the patterns at http://www.martinfowler.com/eaaCatalog/.

It is hard to go into detail about the book, since it would involve discussing a lot of the patterns – but I would just recommend it for any developer, you will learn something!

The two scripts are almost identical. Actually the only difference is the action the shell script should call (add or remove). The rest of the scripts are completely the same.

I call this file addhost.

using terms from application "Quicksilver"
	on process text txt
		set the_password to "YOURPASSWORD"
		repeat with delimiter_position from 1 to (length of txt)
			if character delimiter_position of txt = " " then exit repeat
		end repeat
		if delimiter_position = (length of txt) then
			set hostname to txt as string
			set ipaddress to ""
		else
			set hostname to characters 1 thru (delimiter_position - 1) of txt as string
			set ipaddress to characters (delimiter_position + 1) thru (length of txt) of txt as string

		end if

		do shell script "sudo hosts.sh add " & hostname & " " & ipaddress password the_password with administrator privileges

		return nothing
	end process text
end using terms from

I call this file removehost.

using terms from application "Quicksilver"
	on process text txt
		set the_password to "YOURPASSWORD"
		repeat with delimiter_position from 1 to (length of txt)
			if character delimiter_position of txt = " " then exit repeat
		end repeat
		if delimiter_position = (length of txt) then
			set hostname to txt as string
			set ipaddress to ""
		else
			set hostname to characters 1 thru (delimiter_position - 1) of txt as string
			set ipaddress to characters (delimiter_position + 1) thru (length of txt) of txt as string

		end if

		do shell script "sudo hosts.sh remove " & hostname & " " & ipaddress password the_password with administrator privileges

		return nothing
	end process text
end using terms from

Now I am able to create a local domain by opening Quicksilver (double-control in my case) press period, write the domain name, press tab, and select the addhost action (ad is enough in my case). Removing is just as easy – the last step is just to select the removehost action (re is enough in my case).

#! /bin/bash
DEFAULT_IP=127.0.0.1
IP=${3:-$DEFAULT_IP}

case "$1" in
  add)
        echo "$IP $2"  >> /etc/hosts
        ;;
  remove)
        sed -ie "\|^$IP $2\$|d" /etc/hosts
        ;;

  *)
        echo "Usage: "
		echo "hosts.sh [add|remove] [hostname] [ip]"
		echo
		echo "Ip defaults to 127.0.0.1"
		echo "Examples:"
		echo "hosts.sh add testing.com"
		echo "hosts.sh remove testing.com 192.168.1.1"
        exit 1
        ;;
esac

exit 0

As you can see the script defaults the ip to 127.0.0.1 for easy creation of local domains. Next step is to create a quicksilver (and a gnome do) plugin for easy creation without ever touching the terminal. (Even though we all love the terminal, right?)

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