DZone Snippets: Nicwilliams's Code Snippets

Pretty print in Nu

nicwilliams (Dr Nic Williams) — Fri, 18 Jul 2008 00:27:26 GMT

I miss the 'pp' helper method in Ruby. Fortunately Nu has "-description" method on objects, which is like a #to_pretty_print method in Ruby. So, implementing "pp" takes one line of code:



(function pp (obj) (puts (obj description)))

And for a demonstration:



$ nush

Nu Shell.

% (function pp (obj) (puts (obj description)))

(do (obj) ((puts (obj description))))

% (pp (array 1 2 3 (array "a" "b" 10)))

(

    1,

    2,

    3,

        (

        a,

        b,

        10

    )

)

Thanks to Patrick Thomson for this!

Exploring context and globals with Nu

nicwilliams (Dr Nic Williams) — Fri, 18 Jul 2008 00:19:43 GMT

From Tim in mailing list:

Global name definitions are put into the symbol table; that is
slightly more efficient than normal assignments (such as those made
with the set, macro, and function operators), which are kept in
NSDictionaries. It also makes them easier to use in Nu code that is
called from Objective-C without specifying a context, which you can do
by sending the evalWithContext: message to a parsed code object with a
nil argument. Usually that happens in Objective-C, but since you can
send nearly any ObjC message from Nu, here's a little demo in nush
[ed: I expanded it to show more information]:



$ nush

Nu Shell.

% (parse "(puts 22)")

(progn (puts 22))

% (set prog (parse "(puts 22)"))

(progn (puts 22))

% (prog class)

NuCell

% (set progx (parse "(puts x)"))

(progn (puts x))

% (progx class)

NuCell

% (set x 23)

23

% (x class)

NSCFNumber

% (eval progx)

23

()

% (prog evalWithContext: nil)

22

()

% (progx evalWithContext: nil)

NuUndefinedSymbol: undefined symbol: x

% (progx evalWithContext: (context))

23

()

% (global x 50)

50

% (progx evalWithContext: (context))

23

()

% (progx evalWithContext: nil)

50

()

Find ports used by applications on Mac OS X (i.e. netstat for os x)

nicwilliams (Dr Nic Williams) — Mon, 30 Jun 2008 00:06:33 GMT

netstat on os x doesn't do what you hope it does - show port numbers for applications.

Here's a snippet for your .bash_profile:



# replacement netstat cmd to find ports used by apps on OS X

alias netstat_osx="sudo lsof -i -P"

(thx Lachie Cox)

Convert cp1252-> utf-8 character set (python and ruby)

nicwilliams (Dr Nic Williams) — Wed, 16 Apr 2008 11:39:47 GMT

Oooh, I hate character sets. Specifically that there are more than one of them. Here is a Ruby version of a Python script I found to convert cp1252 (aka windows-1252) into utf-8.



  def clean_up dirty_text

    newstr = ""

    dirty_text.length.times do |i|

      character = dirty_text[i]

      newstr += if character < 0x80

        character.chr

      elsif character < 0xC0

        "\xC2" + character.chr

      else

        "\xC3" + (character - 64).chr

      end

    end

    newstr

  end

The original Python script was (http://miscoranda.com/96):



#!/usr/bin/python

import sys

for c in sys.stdin.read(): 

   if ord(c) < 0x80: sys.stdout.write(c)

   elif ord(c) < 0xC0: sys.stdout.write('\xC2' + c)

   else: sys.stdout.write('\xC3' + chr(ord(c) - 64))

Array#pad!

nicwilliams (Dr Nic Williams) — Mon, 07 Apr 2008 10:44:20 GMT

My ri docco says there is an Array#pad! but runtime Ruby says there isn't. Bah. So I wrote one:



class Array

  def pad!(expected_length, pad_item = nil)

    while expected_length > length

      self << pad_item

    end

    self

  end

end

TextMate snippet for load_model methods in Rails controllers

nicwilliams (Dr Nic Williams) — Mon, 07 Jan 2008 00:26:45 GMT

With nested routes, I find I create a lot of controller methods like:



def load_user

  @user = User.find(params[:user_id]) if params[:user_id]

Here's a TextMate snippet, so you can just type: defmodel, TAB, user, TAB, and you're done.

Snippet:



def load_${1:model}

	@$1 = ${1/[[:alpha:]]+|(_)/(?1::\u$0)/g}.find(params[${2::$1_}id])${3: if params[:$1_id]}

end

Activation: defmodel
Scope: source.ruby.rails

I have this in the Ruby on Rails bundle, but you can put it anywhere. Its the scope that is important.

Upgrade rubygems and/or specific gems themselves via capistrano

nicwilliams (Dr Nic Williams) — Wed, 19 Dec 2007 22:10:32 GMT

When a latest RubyGems is released (e.g. 0.9.5 recently) or Rails (e.g. 2.0.2) you might want to push those upgrades to all your production machines.

Add these two tasks to your deploy.rb capistrano file (add namespaces for cap2.0 if you like)



  desc "Updates RubyGems version"

  task :gem_update_system do

    sudo "gem update --system"

  end



    

  desc "Install a RubyGem from remote source"

  task :gem_install do

    puts "USAGE: GEM=gemname cap gems_install" and next unless ENV['GEM']

    sudo "gem install #{ENV['GEM']} --no-ri --no-rdoc"

  end

To upgrade rubygems and rails, for example:



cap gem_update_system

GEM=rails cap gem_install

Checkout a Git clone of an SVN repository in parent folder

nicwilliams (Dr Nic Williams) — Thu, 22 Nov 2007 22:35:30 GMT

Here is a quick executable cmd that you run inside a folder checked out with Subversion. It will clone the repository using Git into the parent folder as <projname>.git

Stick this code into ~/bin/gitify and add ~/bin to your path:



#!/usr/bin/env ruby -wKU



# get svn info location

svnurl = `svn info | grep "^URL:"`.gsub('URL: ','').chomp



# project = basename

project = File.basename(Dir.pwd)



puts cmd = "git-svn clone #{svnurl} ../#{project}.git"



`#{cmd}`

Auto-populate socket value in rails database.yml using TextMate snippet

nicwilliams (Dr Nic Williams) — Mon, 16 Jul 2007 07:30:51 GMT

When using mysql for rails apps, you may need a socket: value. I can never remember mine. So I added a TextMate snippet to find it. (read below for non-TextMate)

Snippet text:



socket: `mysql_config --socket`

Activation: socket:

Scope selector: source.yaml - string

Usage:

In your database.yml, go to the line socket: , delete any blank spaces til the cursor is at the colon, then press TAB and wait. The line will be updated with the socket location.

Non-TextMate

If you don't have textmate, you can get your socket location using:



mysql_config --socket

And paste the result into your database.yml

Dump postgres production data into development database

nicwilliams (Dr Nic Williams) — Sun, 06 May 2007 09:00:17 GMT

When bug requests come in, its great to grab a copy of the current production (or system test env) data and sync it into your development database.

Here's a capistrano recipe for postgresql:



desc "Dumps target database into development db"

task :sync_db do

  env   = ENV['RAILS_ENV'] || ENV['DB'] || 'production'

  file  = "#{application}.sql.bz2"

  remote_file = "#{shared}/log/#{file}"

  run "pg_dump --clean --no-owner --no-privileges -U#{db_user} -h#{db_host} #{db_name}_#{env} | bzip2 > #{file}" do |ch, stream, out|

    ch.send_data "#{db_password}\n" if out =~ /^Password:/

    puts out

  end

  puts rsync = "rsync #{user}@#{domain}:#{file} tmp"

  `#{rsync}`

  puts depackage = "bzcat tmp/#{file} | psql #{local_db_dev}"

  `#{depackage}`

end