Kevin Tran duykhoa

Originally published in June 2008

When hiring Ruby on Rails programmers, knowing the right questions to ask during an interview was a real challenge for me at first. In 30 minutes or less, it's difficult to get a solid read on a candidate's skill set without looking at code they've previously written. And in the corporate/enterprise world, I often don't have access to their previous work.

To ensure we hired competent ruby developers at my last job, I created a list of 15 ruby questions -- a ruby measuring stick if you will -- to select the cream of the crop that walked through our doors.

What to expect

Candidates will typically give you a range of responses based on their experience and personality. So it's up to you to decide the correctness of their answer.

Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

Setting up a SSL Cert from Comodo

I use Namecheap.com as a registrar, and they resale SSL Certs from a number of other companies, including Comodo.

These are the steps I went through to set up an SSL cert.

Purchase the cert

In Rails 3

NOTE: This post now lives (and kept up to date) on my blog: http://hakunin.com/rails3-load-paths

If you add a dir directly under app/

Do nothing. All files in this dir are eager loaded in production and lazy loaded in development by default.

If you add a dir under app/something/

Opening and closing an SSH tunnel in a shell script the smart way

I recently had the following problem:

From an unattended shell script (called by Jenkins), run a command-line tool that accesses the MySQL database on another host.
That tool doesn't know that the database is on another host, plus the MySQL port on that host is firewalled and not accessible from other machines.

We didn't want to open the MySQL port to the network, but it's possible to SSH from the Jenkins machine to the MySQL machine. So, basically you would do something like

ssh -L 3306:localhost:3306 remotehost

Description

This simple script will take a picture of a whiteboard and use parts of the ImageMagick library with sane defaults to clean it up tremendously.

The script is here:

#!/bin/bash
convert "$1" -morphology Convolve DoG:15,100,0 -negate -normalize -blur 0x1 -channel RBG -level 60%,91%,0.1 "$2"

	#ack is a tool like grep, designed for programmers with large trees of heterogeneous source code

	#to install ack, see http://betterthangrep.com/
	#to use ack, launch terminal (mac osx) and type 'ack <some_keywords>'
	#ack will search all files in the current directory & sub-directories

	#here's how I have my config file setup. this file is located on mac osx here
	# ~/.ackrc

	# Always sort the files

	# STEP 1: VERIFY THAT YOU DO NOT ALREADY HAVE POSTGRESQL INSTALLED ON YOUR SYSTEM
	ps ax \| grep postgres

	# STEP 2: INSTALL POSTGRESQL ON YOUR SYSTEM
	sudo apt-get update
	sudo apt-get install postgresql-9.1

	# List All Postgres related packages
	dpkg -l \| grep postgres

	require 'mina/bundler'
	require 'mina/rails'
	require 'mina/git'
	require 'mina/rvm'

	# Usually mina focuses on deploying to one host and the deploy options are therefore simple.
	# In our case, there is a number of possible servers to deploy to, it is therefore necessary to
	# specify the host that we are targeting.
	server = ENV['server']
	# Since the same host can have multiple applications running in parallel, it is necessary to

	require 'fileutils'

	desc "Create nondigest versions of all ckeditor digest assets"
	task "assets:precompile" => :environment do
	fingerprint = /\-([0-9a-f]{32})\./
	for file in Dir["public/assets/ckeditor/*/"]
	# Skip file unless it has a fingerprint
	next unless file =~ fingerprint

	# Get filename of this file without the digest