Mostly this is just farting around but I thought I’d post about it because it’s an interesting idea, at least in theory.

GUIDs are good but I wanted to do one better. So I created SUUIDs. Super Universally Unique IDs. The format of the current version, v2.0, is thus:

2/xxxxxxxx-xxxxxxxx-xxxxxxxx-xxxxxxxx-xxxx

Where x is a case-sensitive alphanumeric character. This gives us somewhere in the area of 3.35×10^64 possible combinations, and a lot of interesting characteristics.

• For example, if the address space of a given ID is all hexadecimal, and the last four characters are IPv6, this functions just as well as an IPv6 address format. Thus, The IPv6 address 2001:0db8:0000:0000:0000:0000:1428:57ab is notated as 2/20010db8-00000000-00000000-142857ab-IPv6. If a field contains all the same character, you can replace the ending hyphen with a comma and the field with a single instance of that character, so that IP address could also be 2/20010db8-0,0,142857ab-IPv6.
• In the same token, the same rules apply to a message that ends in 0MD5 — that’s an MD5 checksum as well as a unique address.

An implementation in Ruby:

	module SUUID
	  def self.gen
	   chars = ("a".."z").to_a + ("1".."9").to_a + ("A".."Z").to_a
	   x = [8, 8, 8, 8, 4]
	   x.map! {|i| i = Array.new(i, '').collect{chars[rand(chars.size)]}.join }
	   return "2/" + x.join('-')
	  end
	end

It’s not pretty, but it gets the job done. You could always throw a more random source of entropy at it, use the system date, time, whatever. Don’t particularly care about the implementation.

Here’s what a couple look like — to get used to the idea :-)

2/f9nuBgzm-HGTE4bSK-ZEfkfsRp-T3SXgpXA-5LNC
2/hoyOCd7o-V48NQGvv-OS5RBDIl-CG1FRNqG-Xd3j
2/sUZd6aGa-1J55rs9C-lxH1mvPA-I9PAvkOh-ZLVj

Additionally, you can omit the version number, which so far still allows for distinction between version 1 and version 2 (version 1 didn’t have lowercase letters). This means you have a nice set of directory names at your disposal.

mkdir /DOMejDTy-APESCioG-yyXpXBNL-lYAuQogL-Uep9
mkdir `curl -X POST http://example.com/suuid/provider`

I have no idea how checksums, hashes, verified randomness all fit into something like this. Just something fun and stupid to keep me occupied today.

I’ve spent the past couple of hours futzing around with Sinatra and Rack being hooked up to the latest Phusion Passenger, and I’ve come across a bizarre problem. Let’s see what I can illustrate.

I have a Slicehost VPS, and I threw a DynDNS address at it because I didn’t feel like registering a domain name for something that was essentially supposed to be a playground. I set it up so that subdomains would also get redirected to my slice, since I didn’t want Phusion interfering with some PHP, Trac, and SVN stuff I also have running on it. My configuration basically looks like this:

/etc/apache2/sites-available/phusion-passenger

<VirtualHost *:80>
        ServerAdmin webmaster@localhost
        ServerName  projects.example.com
        DocumentRoot /var/projects
        <Directory /var/projects>
                Options -Indexes
        </Directory>
        RackBaseURI /sinatra_test
</VirtualHost>

Then I set up /webapps/sinatra_test, along with the latest version of Sinatra, as outlined on the “Bleeding Edge” section of the Sinatra website. The Phusion Passenger documentation provides instructions on the proper way to format your Rack directories, which includes a tmp directory, a public directory, and a config.ru. Add my actual Sinatra application, and I have a setup that looks like this:

root@slice:/webapps/sinatra_test# ls -l
total 16
-rw-r--r-- 1 www-data www-data  326 Jul 27 15:19 config.ru
-rw-r--r-- 1 www-data www-data  235 Jul 27 15:44 myapp.rb
drwxr-xr-x 2 www-data www-data 4096 Jul 27 05:54 public
lrwxrwxrwx 1 www-data www-data   10 Jul 27 06:13 sinatra -> ../sinatra
drwxr-xr-x 2 www-data www-data 4096 Jul 27 15:46 tmp

All good to go, right? You’d think. There’s some bizarre things going on with Phusion, or Rack, or Sinatra, in terms of discerning correct actions and mapping them to URL endpoints.

My Sinatra application:

myapp.rb

  $:.unshift File.dirname(__FILE__) + '/sinatra/lib'
  require 'sinatra'
 
  get '' do
    "Rootless test"
  end
 
  get '/' do
    "Root test"
  end
 
  get '/other' do
    "Other application part"
  end
 
  get '/other/' do
    "This is a different endpoint"
  end

As well as the config.ru I’m using for it:

config.ru

  $:.unshift File.dirname(__FILE__) + '/sinatra/lib'
  require 'sinatra'
 
  Sinatra::Application.default_options.merge!(
    :run => false,
    :env => :development,
    :raise_errors => true,
    :app_file => 'myapp.rb'
  )
 
  log = File.new("sinatra.log", "a")
  STDOUT.reopen(log)
  STDERR.reopen(log)
 
  require 'myapp'
  run Sinatra.application

And this is what I get when I play with curl.

~ $ curl http://projects.example.com/sinatra_test/other
Other application part

~ $ curl http://projects.example.com/sinatra_test/other/
This is a different endpoint

~ $ curl http://projects.example.com/sinatra_test
Rootless test

~ $ curl http://projects.example.com/sinatra_test/
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>403 Forbidden</title>
</head><body>
<h1>Forbidden</h1>
<p>You don't have permission to access /sinatra_test/
on this server.</p>
...

What’s going on? other and other/ are considered different endpoints, which makes sense, I imagine. I’m not an HTTP wizard. Even if the root of the sinatra_test directory and the same root with an ending slash are considered different endpoints, then why wouldn’t I be able to access the latter? Especially with it defined explicitly in my Sinatra application? Even more, especially since if this was a distinction, as in the case of other and other/, but isn’t working the same way for the root URL?

Curioser and curioser. I have no idea if the problem is with Sinatra, Rack, Phusion, or my Apache configuration, and I’ve played around with omitting or specifying explicitly an ending forward slash for the DocumentRoot and RackBaseURI. Some of you may point out that I’ve specified -Indexes for the VirtualHost configuration, but if that isn’t specified, then navigating to http://projects.example.com/sinatra_test/ generates an empty directory listing, since it is pointing to my empty public folder.

So that’s where I am. Any insight would be appreciated, but I’ll keep hacking at it.

EDIT Well, there’s some relief for me - disabling mod_autoindex in Apache does the trick. I’m still not sure how I feel about the two endpoints — one with trailing slash and one with — being distinct, but at least there’s a viable solution. If you don’t have a reason to use mod_autoindex, disable it, and it will stop the interference. If you do need it, I’m not entirely sure what you would do.

Why shouldn’t we be allowed to have multiple files with the same name in one directory, so long as they’re all different versions of the same file?

To wit:

$ ls -al
-rw-r--r--   1 ardekantur  staff      60 Jul  6 23:20 hello_world.c
-rw-------   1 ardekantur  staff      62 Jul  5 13:00 hello_world.c
-rw-r--r--   1 ardekantur  staff      61 Jul  7 00:35 hello_world.c

No PHC.

Pixelmator’s lasso tool is all or nothing. That is to say, if you wish to select something with it, you must hold down your mouse button the entirety of the time you are making your selection. This makes it impossible to do anything but the most basic of selections. Nothing refined or nuanced. This is extremely frustrating.