Random Ruby Thoughts

Deploy Rails+Unicorn+Nginx+God using Mina

Thu, 23 Aug 2012 22:44:31 +0400

Deploy Rails+Unicorn+Nginx+God using Mina:

No Cap, go Mina!

"Some like TDD, others prefer BDD, I prefer BMDD. Black Magic Driven Development that is."

Thu, 26 Jul 2012 17:05:21 +0400

“Some like TDD, others prefer BDD, I prefer BMDD. Black Magic Driven Development that is.”

- leprosorium.ru

OpenSSL::SSL::SSLError & SSL_set_tlsext_host_name

Mon, 06 Feb 2012 17:20:00 +0400

In case you’ve hit OpenSSL::SSL::SSLError or SSL_set_tlsext_host_name error, and you have installed PostgreSQL using official installer - please, read on.

It seems that official PostgreSQL installer somehow modifies openssl and gems that was built upon it.

You should try to remove your PG installation completely (you may want to backup your pg data directory first, usually it’s ‘/Library/PostgreSQL/<version>/data’), and then re-install postgres using Homebrew. It helped in my case.

And, if you backed up your data directory, do the following:

sudo chmod -R <your_username> <backup_path>

Now you can run your PG server with all your data intact:

postgres -D <backup_path>

Full script for the lazy (it may not be fully working tho, I don’t remember it completely, so use at your own risk and check every step):

sudo chmod -R <your_username> /Library/PostgreSQL/<version>/data
cp /Library/PostgreSQL/<version>/data /usr/local/var/postgres
open /Library/PostgreSQL/9.0/uninstall-postgresql.app
...perform uninstall...
brew install postgresql # for the install of the latest version. See "man brew" for versions info
createuser
...create postgres user or superuser...
postgres -D /usr/local/var/postgres/data

…well, something like that. It should be working now. Good luck!

Want to know actual amount of time your tests run?

Thu, 28 Jul 2011 17:33:00 +0400

Have you often seen this?

~/project$ rspec spec/controllers/some_controller.rb
.......

Finished in 1.01159 seconds
7 examples, 0 failures

Is that supposed to be less than a second? You wish! Actually, your tests will run 20+ seconds or so: launching an instance and preparing stuff for testing is quite time consuming.

But what if you want to now exactly how long your tests run? The simplest and quickest solution is to add the following line to your ~/.profile:

alias rake="time rake"

Your tests will now output something like this:

~/project$ rspec spec/controllers/some_controller.rb
.......

Finished in 1.01159 seconds
7 examples, 0 failures

real	0m28.330s
user	0m18.682s
sys	0m1.886s

Not too pretty, but it does the job.

Disable window shadows in Mac OS X

Thu, 02 Jun 2011 11:29:31 +0400

TL;DR: Nocturne, night mode, disable shadows.

Some time ago I’ve noticed that my screen on MacBook Pro starting to show a horizontal line across the whole screen, left to right, just above the dock. It’s like, if you leave a monitor turned on for a very long time with high-contrast wallpaper on desktop, image will be burned up on the screen and it will take weeks of white glow to get rid of it.

Reason for such a weird artifact was found shortly after. If you open 2+ windows on “full-screen”, stretched from menu bar to dock, they’ll be dropping very, very dark and strong shadow. And if you live with that on daily basis (on work I have a browser, code editor, and console stretched at max), and if you have a light wallpaper that contrasts with the shadow, you’ll have the same problem as I do: usually barely visible (but very annoying when watching movies) contrast dark bar at about 2 inches from the bottom edge of monitor, just above your dock.

There’s two solutions to this: 1. don’t use light wallpapers, instead try some dark ones, at least at bottom part of the screen; 2. Use Nocturne to disable shadows. It’s very easy to get on with it, really.

Restart all Pow instances

Wed, 18 May 2011 12:16:00 +0400

As I recently switched from Passenger to Pow to serve all my local Rails, Sinatra and Rack projects in development, it became obvious that I need a command to restart ALL Pow instances at once. And instead of doing "touch tmp/restart.txt" every time in project root, I’ve ended up with this simple bash alias:

alias reall='touch ~/.pow/restart.txt; echo "Touch."'

Hope you’ll find it usefull.

Recursively Setting Deep Hash Value

Fri, 15 Apr 2011 21:22:00 +0400

ilovemetaprogramming:

I’ve always wanted to be able to do something like:
my_hash = {}
my_hash["Cloud"]["Stats"]["Strength"] = 100
p my_hash # => {"Cloud"=>{"Stats"=>{"Strength"=>100}}}
So I whipped up the code below and now I can! Metaprogramming wins again!
class SuperHash < Hash
  def initialize
    super { |h, k| h[k] = SuperHash.new }
  end
end

sh = SuperHash.new
sh["foo"]["bar"]["baz"] = "wtf"
pp sh
All this does is set the default value for the SuperHash to a new instance of SuperHash. Very…very cool.

Photo

Mon, 07 Mar 2011 14:02:10 +0300

Ruby's "method" method

Thu, 10 Feb 2011 10:54:00 +0300

Ever wanted to know, where exactly in code a method was defined?

>> String.new.method(:underscore).source_location => ["/path/to/gems/activesupport-3.0.3/lib/active_support/core_ext/string/inflections.rb", 82]

InnoDB vs MyISAM

Thu, 10 Feb 2011 10:43:00 +0300

TL;DR: writes.count > reads.count ? InnoDB : MyISAM;

There’s a lot of articles all over teh internetz about comparing InnoDB vs MyISAM, but this note is rather like ‘note to self’. TL;DR says it all.

Decision QA, I’ve found here:

InnoDB if:

your table is going to be inserted, deleted, and updated much much more than it is going to be selected
you prefer/require relational database design

MyISAM if:

you need full-text search
disk-space or ram is an issue
in doubt?..

Evalulate multiple methods using send method

Sat, 21 Aug 2010 01:43:00 +0400

Ever wanted to pass a list of methods to an object? Send allows you to call one method on an object, but what if you need to call a few methods depending on object’s type?

I like to be short and straightforward in my speeches, so here’s the hack of the Object class:

class Object
  def sends(method_chain='')
    method_chain = method_chain.to_s
    return self if method_chain.empty?
    self.instance_eval { eval method_chain }
  end

  def try_sends(method_chain='')
    begin
      self.sends method_chain
    rescue NoMethodError
      nil
    end
  end
end

Now you can pass a string as param, which gets evaluated on an object’s instance.

# Example:
methods = "power!(2).div(57).+(12).to_f"
42.instance_eval { eval methods } #=> 42.0

# Real world example:
s = Subject.last
s.sends 'site.country.name' #=> 'United kingdom'

# And in case of possible nils...
s.site.country_id = 0
s.site.save
s = Subject.last
s.try_sends 'site.country.name' #=> nil

There is also another way to achieve the same result - passing an array instead of string, or even more complex structures, if needed, but it’s a matter of taste. I prefer using strings.

class Object
  # obj.call_method_chain_array ['method1', 'method2', 'method3', ...]
  def call_method_chain_array(method_chain)
    return self if method_chain.empty?
    method_chain.inject(self){|object,method| object.send(method.intern)}
  end

  # obj.call_method_chain_string 'method1.method2.method3'
  def call_method_chain_string(method_chain)
    return self if method_chain.empty?
    method_chain.split('.').inject(self){|object,method| object.send(method.intern)}
  end
end

Downside of this approach is that calling send for each method in chain is less effective, depending on chain length: up to 30 times slower on some ActiveRecord objects with many relations. So I’ll stick with evals.

PS. This hack is already included in my CorX gem

CorX – Handful set of ruby Core eXtensions

Thu, 12 Aug 2010 12:22:00 +0400

Just published a handful set of extensions to core ruby classes I use every day. Got tired of copying them over and over again, so I’ve just packaged ‘em as a gem and published.

They are not yet tested nor well documented, so if you’re willing to help, I will be thankful for any assistance. Just drop a line to alfuken on gmail box.

Links: Gem, Github

Markaby is better than Haml!

Thu, 29 Jul 2010 13:56:00 +0400

Markaby is better than Haml!:

And it looks and feels much better in ruby-ish world (and code), rather than python-ish haml. And what is most important — it’s readable.

JavaScript Console without browser

Thu, 29 Jul 2010 13:50:00 +0400

Ever wanted to run/test/debug JavaScript in console without having to launch your web browser? Well, now you can!

Run this line of code in your terminal and you’re good to go (just make sure /opt/local/bin is in your PATH system variable):

sudo ln -s /System/Library/Frameworks/JavaScriptCore.framework/Versions/A/Resources/jsc /opt/local/bin

Restart your Terminal, and type jsc --help:

$ jsc --help
Usage: jsc [options] [files] [-- arguments]
  -d         Dumps bytecode (debug builds only)
  -e         Evaluate argument as script code
  -f         Specifies a source file (deprecated)
  -h|--help  Prints this help message
  -i         Enables interactive mode (default if no files are specified)
  -s         Installs signal handlers that exit on a crash (Unix platforms only)

You can eval piece of code when running console:

$ jsc -i -e 'function foo(arg){return arg ? arg+"ed!" : "bar!";}' -i
> foo()
bar!
> foo("baz")
bazed!

or even eval whole files (test.js contains foo() function from above)

$ jsc -i test.js
> foo("k'")
k'ed!

That’s it. Have fun!

Upload and download files in Sinatra

Thu, 29 Jul 2010 12:28:00 +0400

List

get '/' do
  list = Dir.glob("./files/*.*").map{|f| f.split('/').last}
  # render list here
end

Upload

post '/' do
  tempfile = params['file'][:tempfile]
  filename = params['file'][:filename]
  File.copy(tempfile.path, "./files/#{filename}")
  redirect '/'
end

Download

get '/download/:filename' do |filename|
  send_file "./files/#{filename}", :filename => filename, :type => 'Application/octet-stream'
end

Delete

get '/remove/:filename' do |filename|
  File.delete("./files/#{filename}")
  redirect '/'
end

A pseudo-intellisense for Textmate

Wed, 28 Jul 2010 19:02:00 +0400

A pseudo-intellisense for Textmate

How to Use Mongrel as default server for Rails 3

Wed, 28 Jul 2010 16:42:00 +0400

Just add following line to Gemfile:

gem "mongrel"

Photo

Wed, 28 Jul 2010 15:12:00 +0400

Invoke rake task from within rake task

Wed, 28 Jul 2010 13:14:00 +0400

namespace :afternoon do
  task :make_coffee do
    Rake::Task['morning:make_coffee'].invoke
    puts "Ready for the rest of the day!"
  end
end

Taken from Jason Seifer’s great Rake Tutorial

Foo, bar, and friends.

Wed, 28 Jul 2010 12:50:00 +0400

When foo, bar, and baz is just not enough. ;)

Foo, bar, baz, qux, quux, corge, grault, garply, waldo, fred, plugh, xyzzy, thud, wibble, wobble, wubble, flob.