I then came across the parsimonious Scalatra. I love it it’s light elegant and doesn’t require you to do too much to get started. I have not used it long enough to say that this is going to be my weapon of choice for any future developments but it’s a very strong candidate.

I only just now discovered the Play framework and on first glance it’s a brilliant looking MVC framework, honing in on my Zend experience with PHP. It feels like Zend, I have not actually started writing anything in it yet but I am going to attempt a full blown web project in it and see how that goes. Perhaps something for an EC2 instance.

#!/bin/bash

cd ~

echo --------------------------------------------------------------------------------------------
echo - Getting SBT Launcher
echo --------------------------------------------------------------------------------------------
wget http://typesafe.artifactoryonline.com/typesafe/ivy-releases/org.scala-tools.sbt/sbt-launch/0.11.0/sbt-launch.jar

printf 'java -Xmx512M -jar `dirname $0`/sbt-launch.jar "$@"' > sbt

chmod +x ./sbt

echo --------------------------------------------
echo - Move sbt and sbt-lauch to share
echo --------------------------------------------

sudo mv sbt /usr/share/sbt
sudo mv sbt /usr/share/sbt-launch.jar

echo --------------------------------------------------------------------------------------------
echo - symlinking sbt and sbt-lauch to /usr/bin/{sbt, sbt-lanch.jar}
echo --------------------------------------------------------------------------------------------
sudo ln -s /usr/share/sbt /usr/bin/sbt
sudo ln -s /usr/share/sbt-launch.jar /usr/bin/sbt-launch.jar

I suppose, when I get time I can make this accept parameters so you can specify the version of SBT you want and the file name you want to use etc but for now this should suffice…
comments welcome.

Simply copy this and paste into a file, name it whatever you want, and make it executable with chmod +x

#!/bin/bash

cd ~

echo --------------------------------------------------------------------------------------------
echo - Getting Scala 2.9.0.1
echo --------------------------------------------------------------------------------------------
wget http://www.scala-lang.org/downloads/distrib/files/scala-2.9.0.1.tgz

echo --------------------------------------------------------------------------------------------
echo - Decompressing
echo --------------------------------------------------------------------------------------------
tar zxf scala-2.9.0.1.tgz

echo --------------------------------------------------------------------------------------------
echo - moving scala to /usr/share/scala
echo --------------------------------------------------------------------------------------------
sudo mv scala-2.9.0.1 /usr/share/scala

echo --------------------------------------------------------------------------------------------
echo - Symlinking executables
echo --------------------------------------------------------------------------------------------
sudo ln -s /usr/share/scala/bin/scala /usr/bin/scala
sudo ln -s /usr/share/scala/bin/scalac /usr/bin/scalac
sudo ln -s /usr/share/scala/bin/fsc /usr/bin/fsc
sudo ln -s /usr/share/scala/bin/sbaz /usr/bin/sbaz
sudo ln -s /usr/share/scala/bin/sbaz-setup /usr/bin/sbaz-setup
sudo ln -s /usr/share/scala/bin/scaladoc /usr/bin/scaladoc
sudo ln -s /usr/share/scala/bin/scalap /usr/bin/scalap

import sbt._

class MyDataEngineProject(info: ProjectInfo)
    extends DefaultProject(info) {
  // Declare MySQL connector Dependency
  val mysql = "mysql" % "mysql-connector-java" % "5.1.17"
}

Once you have got this in project/build/MyDataEngineProject.scala, you are ready to start the connection stuff. In src/main/scala you can start creating your application here. I use the “def main” approach so when i start from the command line i simply pass in my parameters and I’m ready to go:

import java.sql.{Connection, DriverManager, SQLException, ResultSet}

object DataEngine {

	private var driverLoaded = false

	private def loadDriver()  {
		try{
			Class.forName("com.mysql.jdbc.Driver").newInstance
			driverLoaded = true
		}catch{
			case e: Exception  => {
			    println("ERROR: Driver not available: " + e.getMessage)
			    throw e
			}
		}
	}

	def main(args: Array[String]) {
		if (args.length < 1){
			println("No arguments provided, exitting...")
			return
		}
		println ("Attempting to load MySQL JBDC Driver...")
		println
		this.synchronized {
		  if(! driverLoaded) loadDriver()
		}

		val conString = "jdbc:mysql://localhost:3306/db_name?user="+args(0)+"&password="+args(1)
		classOf[com.mysql.jdbc.Driver]
		val con = DriverManager.getConnection(conString)
		try{
			val handle = con.createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY)
			val rs = handle.executeQuery("select * from auth limit 1")
			println ("Connection established...")
			while(rs.next){
				println("User Handle: "+rs.getString("handle"))
			}
		}catch{
			case e: Exception  => {
		    	println("ERROR: No connection: " + e.getMessage)
		    	throw e
		  	}
			case _ => println("A problem!")
		}finally{
			println("Closing connection and exiting...")
			con.close()
		}
  	}
}

Save the file as Main.scala and you can just type in run with your db username and password as space-separated arguments and you’re ready to go. Of course you will need to change some bits in here to reflect your database schema, but aside that it’s that simple. In my next post I will work on inserting data and updating data as well.

Despite using the correct syntax:

\begin{figure}[htb]
    \begin{center}
        \includegraphics{image.png}
    \end{center}
    \caption{Fig 1: image}
    \label{fig1}
\end{figure}

You may find a box with with only the image path being displayed as your image. Please check that you are not using the “draft” argument at the top of your document when specifying your document class. A bit like

\documentclass[12pt,a4paper,draft]{article}

Make sure there is no “draft” in there so that it reads

\documentclass[12pt,a4paper]{article}

Spent about half an hour trying to figure out why everyone else’s images were displaying except mine.

Not only does it look identical to my favourite text editor / IDE of all time – gEdit. It supports syntax highlighting, decent support for BibTex referencing. It also has a very user friendly interface and it’s also customizable as per any GTK interface in GNOME.

I have not checked if there are versions for other Operating Systems but I am pretty certain anyone wishing to try this out with any Linux distribution can do it with the built in package/software manager, shipped with it.

This is obviously not to say the others do not have advantages over LaTeXila, this is just the one I have felt most at home with. I have tried the LaTex plug-in for gEdit, that is also quite good especially the support you get when using the \cite command, it handily provides a drop down of keys available in any BibTeX files you have referenced in that LaTeX doument. I haven’t played with LaTeXila’s preferences extensively so I am not sure if it has that too.

You can find sourceforge page here http://latexila.sourceforge.net/

$router->addRoute(
                'listingswithpage',
                new Zend_Controller_Router_Route(
                        '/listing/:type/:page',
                        array('controller' => 'listing',
                            'action' => 'index')
                )
        );

Your pagination view helper gets a bit thrown if you go by the documentation. The first thing you need to do is find a way to specify the first page initially. I went with specifying my first page in my route definition so it looked something like this

$router->addRoute(
                'listingswithpage',
                new Zend_Controller_Router_Route(
                        '/listing/:type/:page',
                        array('controller' => 'listing',
                            'action' => 'index',
                            'page' => 1)
                )
        );

And that worked. Failing that you have to figure out a way to pass the complete URL path to you pagination view which might be something like “controls.phtml” or “pagination.phtml”. and constructing the url properly there.

I will perhaps post a more detailed description of what this means but leave a comment if you are impatient and I will try and respond when I get a moment.

What they all say is to make sure it’s loaded and enabled. I will raise my hand and say it wasn’t that easy for me to find because Ubuntu lays out Apache2 a little differently from say Fedora. First of all in the /etc/apache2 folder there are a few folders to take note of.

sites-enabled and mods-enabled actually tell you what has been enabled or not and not an uncommented list in some httpd.conf file. Basically the folders in there have symbolic links that come from sites-available and mods-available. This perhaps is a better idea as you can add new mods and not have to recompile apache or whatever.

I digress, to enable mod_rewrite in apache2 in Ubuntu 10.04.1 you need to create a symbolic link from mods-available to mods-enabled to do this you can either use the command:

sudo ln -s /etc/mods-available/rewrite.load /etc/mods-enabled/rewrite.load

or if you prefer GUIs you have to run nautilus as root so you can try

sudo nautilus

and navigate to “/etc/mods-available”, right-click on rewrite.load and select “make link” and the cut the new file created called “link to rewrite.load” paste it in mods-enabled and rename it to “rewrite.load ”

Now all you need to do is restart your web server and you’re all set to reroute anyhow you want.

sudo /etc/init.d/apache2 restart