Development on Justin Langhorst

Handling contact forms on static sites

Sat, 03 Sep 2016 22:17:34 -0500

I originally went the route of rolling my own contact form handler. But instead of setting up my own server (even if mostly already written the way I would want it, see contact-form on GitHub), daemonizing it, proxying requests from Nginx, and then remembering how I set it all up 6 months from now, I found another service.

FormKeep look awesome, but their lowest pricing option is way more expensive than I need for a paltry little contact form on a site that barely gets any traffic.

Creating and rotating log files from piped input

Mon, 06 Apr 2015 11:15:31 -0500

On using the rotatelogs tool to rotate files based on time and/or size

Wiki on BeagleBone Black

Sat, 03 Jan 2015 18:00:00 +0000

How to set-up a wiki for home or business use on the BeagleBone Black computer.

Hosting multiple domains with Nginx in Ubuntu 14.04 on Digital Ocean

Sat, 12 Jul 2014 10:04:15 +0000

How to set-up a VPS on Digital Ocean to host multiple sites with the Nginx web-server on top of the Ubuntu 14.04 operating system.

Octopress on S3

Thu, 11 Jul 2013 16:23:23 +0000

How to set-up Octopress, a static blogging engine, on the Amazon S3 service.

Using AirPort Utility 5.6.1 in Lion

Fri, 18 Jan 2013 00:34:34 +0000

How to use AirPort Utility to configure an AirPort Express within OS X Lion.

pbcopy | pbpaste, and opening a new terminal tab in the current working directory

Mon, 31 Oct 2011 15:59:59 +0000

Using the OS X command-line utilities pbcopy and pbpaste within the terminal.

A Big Smile ... Ruby and Erlang

Fri, 25 Aug 2006 12:34:11 -0600

A big smile appeared on my face tonight after typing the following:

-module(math1).
-export([factorial/1]).

factorial(0) -> 1;
factorial(N) -> N * factorial(N-1).

def factorial(n)
  return 1 if n == 0
  n * factorial(n-1)
end

Maybe not so obvious. But check this out:

-module(temp).
-export([convert/2]).

convert({fahrenheit, Temp}, celsius) ->
        {celsius, 5 * (Temp -32) / 9};
convert({celsius, Temp}, fahrenheit) ->
        {fahrenheit, 32 + Temp * 9 / 5};
convert({reaumur, Temp}, celsius) ->
        {celsius, 10 * Temp / 8};
convert({celsius, Temp}, reaumur) ->
        {reaumur, 8 * Temp / 10};
convert({X, _}, Y) ->
        {cannot,convert,X,to,Y}.

This a simple temperature conversion program. Done in Ruby with methods, although not normally the way that I would introduce such functionality into a program:

def convert(from, temp, to)
  case to
    when :celsius     : to_celsius(from, temp)
    when :fahrenheit  : to_fahrenheit(from, temp)
    when :reaumur     : to_reaumur(from, temp)
    else                "cannot convert #{from} to #{to}"
  end
end

def to_celsius(from, temp)
  case from
    when :fahrenheit  : 5.0 * (temp - 32.0) / 9.0
    when :reaumur     : 10.0 * temp / 8.0
    when :celsius     : temp
    else                "cannot convert #{from} to celsius"
  end
end

def to_fahrenheit(from, temp)
  case from
    when :celsius     : 32.0 + temp * 9.0 / 5.0
    when :fahrenheit  : temp
    else                "cannot convert #{from} to fahrenheit"
  end
end

def to_reaumur(from, temp)
  case from
    when :celsius     : 8.0 * temp / 10.0
    when :reaumur     : temp
    else                "cannot convert #{from} to reamur"
  end
end

Yikes! The pattern matching in Erlang functions really comes in handy. Here is the output from both terminals (Erlang then Ruby):

Adding to the Ruby Logger

Fri, 23 Jun 2006 12:34:11 -0600

I’ve been working on some new code at work for a new install. Unfortunately, I’m unable to use the new framework just yet (mainly because it’s not complete), and I needed a workaround for the Ruby Logger to be able to accept .trace calls (we usually use Log4r. Here’s my workaround:

require 'logger'

# Redefine the Logger to allow for TRACE calls.
class Logger
  module Severity
    TRACE = -1
  end
  
  def trace?; @level <= TRACE; end
  
  def trace(progname = nil, &block)
    add(TRACE, nil, progname, &block)
  end
  
  NEW_SEV_LABEL = %w(TRACE DEBUG INFO WARN ERROR FATAL ANY)
  
  def format_severity(severity)
    NEW_SEV_LABEL[severity+1] || 'ANY'
  end
end

Usage example: