DZone Snippets: Technoweenie's Code Snippets

backuping up/restring pgsql

technoweenie (Rick Olson) — Wed, 31 May 2006 00:53:36 GMT

I always forget this, or get it mixed up with MySQL:



pg_dump dbname > dbname.sql

cat dbname.sql | psql dbname

deploy your rails apps on edge rails

technoweenie (Rick Olson) — Tue, 07 Feb 2006 11:07:28 GMT

lib/tasks/rails.rake



desc "Checks out rails"

task :init do

  ENV['SHARED_PATH']  = '../../shared' unless ENV['SHARED_PATH']

  ENV['RAILS_PATH'] ||= File.join(ENV['SHARED_PATH'], 'rails')

 

  checkout_path = File.join(ENV['RAILS_PATH'], 'trunk')

  export_path   = "#{ENV['RAILS_PATH']}/rev_#{ENV['REVISION']}"

  symlink_path  = 'vendor/rails'



  # do we need to checkout the file?

  unless File.exists?(checkout_path)

    puts 'setting up rails trunk'    

    get_framework_for checkout_path do |framework|

      system "svn co http://dev.rubyonrails.org/svn/rails/trunk/#{framework}/lib #{checkout_path}/#{framework}/lib --quiet"

    end

  end



  # do we need to export the revision?

  unless File.exists?(export_path)

    puts "setting up rails rev #{ENV['REVISION']}"

    get_framework_for export_path do |framework|

      system "svn up #{checkout_path}/#{framework}/lib -r #{ENV['REVISION']} --quiet"

      system "svn export #{checkout_path}/#{framework}/lib #{export_path}/#{framework}/lib"

    end

  end



  puts 'linking rails'

  rm_rf   symlink_path

  mkdir_p symlink_path



  get_framework_for symlink_path do |framework|

    ln_s File.expand_path("#{export_path}/#{framework}/lib"), "#{symlink_path}/#{framework}/lib"

  end

end



def get_framework_for(*paths)

  %w( railties actionpack activerecord actionmailer activesupport actionwebservice ).each do |framework|

    paths.each { |path| mkdir_p "#{path}/#{framework}" }

    yield framework

  end

end

Switchtower recipe code:



set :rails_version, 3517

desc "Checks out rails rev ##{rails_version}"

task :after_symlink do

  run <<-CMD

    cd #{current_release} &&

    rake init REVISION=#{rails_version} RAILS_PATH=/home/username/projects/rails

  CMD

end

regex matching in lighttpd configs

technoweenie (Rick Olson) — Thu, 24 Nov 2005 07:44:21 GMT

Match the host name and rewrite paths like /images to blah.com/images:



$HTTP["host"] =~ "^.*\.([^.]+\.[^.:]+)(:|^)" {

  url.rewrite = ( "^/images/(.*)" => "/%1/images/$1",

                 "^/files/(.*)" => "/%1/files/$1",

 "^/$" => "index.html", "^([^.]+)$" => "$1.html")

}

provided by Dreamer3 and annotated here so I can quit bugging him about it.

measure map tags for typo

technoweenie (Rick Olson) — Tue, 08 Nov 2005 03:18:51 GMT

See my associated blog post.



# /app/views/articles/_article.rhtml







# /app/views/articles/_comment.rhtml







# /app/views/articles/read.rhtml

# This is the same as the _article.rhtml snippet, but using the @article instance var instead of the article local var

There's also a javascript include to add to the bottom of your typo theme, but there's no customization required...

freeze_edge for switchtower deployments

technoweenie (Rick Olson) — Sat, 05 Nov 2005 05:14:43 GMT

I run this rake task in the after_symlink event of switchtower to set up the newly deployed app's config files. I rewrote the freeze_edge task to be a little more efficient:

1. checks out rails trunk to shared/rails/trunk if needed
2. updates rails trunk to revision used by the app
3. exports that revision to shared/rails/rev_xxxx
4. links that revision to current/vendor/rails

This way, my app only has a single checkout of the rails trunk. Multiple deployments do not checkout fresh copies, but update to the desired revision and export. If you make multiple deployments using the same rails revision, then only the symlink action is performed. This speeds the task up considerably, and conserves disk space and network traffic.

Set rails version in deploy.rb:
set :rails_version, 2871

Create after_symlink task:

desc "Checks out rails rev ##{rails_version}"

task :after_symlink do

  run "cd #{current_release} && rake init SHARED_PATH=#{shared_path} CURRENT_RELEASE=#{current_release} REVISION=#{rails_version}"

end

init task:

desc "Performs an export of the rails trunk"

task :init do

  return unless ENV['SHARED_PATH'] and ENV['CURRENT_RELEASE']

  puts 'copying files...'

  cp "#{ENV['SHARED_PATH']}/database.yml",  "#{ENV['CURRENT_RELEASE']}/config"

  cp "#{ENV['SHARED_PATH']}/dispatch.fcgi", "#{ENV['CURRENT_RELEASE']}/public"



  puts 'setting permissions...'

  chmod 0600, "#{ENV['CURRENT_RELEASE']}/config/database.yml"

  chmod 0700, "#{ENV['CURRENT_RELEASE']}/public/dispatch.fcgi"

  

  checkout_path = "#{ENV['SHARED_PATH']}/rails/trunk"

  export_path = "#{ENV['SHARED_PATH']}/rails/rev_#{ENV['REVISION']}"

  symlink_path = "#{ENV['CURRENT_RELEASE']}/vendor/rails"



  # do we need to checkout the file?

  unless File.exists?(checkout_path)

    puts 'setting up rails trunk'    

    get_framework_for checkout_path do |framework|

      system "svn co http://dev.rubyonrails.org/svn/rails/trunk/#{framework}/lib #{checkout_path}/#{framework}/lib --quiet"

    end

  end



  # do we need to export the revision?

  unless File.exists?(export_path)

    puts "setting up rails rev #{ENV['REVISION']}"

    get_framework_for export_path, symlink_path do |framework|

      system "svn up #{checkout_path}/#{framework}/lib -r #{ENV['REVISION']} --quiet"

      system "svn export #{checkout_path}/#{framework}/lib #{export_path}/#{framework}/lib"

    end

  end



  puts 'linking rails'

  rm_rf   "vendor/rails"

  mkdir_p "vendor/rails"



  get_framework_for checkout_path, export_path, symlink_path do |framework|

    ln_s File.expand_path("#{export_path}/#{framework}/lib"), "#{ENV['CURRENT_RELEASE']}/vendor/rails/#{framework}/lib"

  end

end



def get_framework_for(*paths)

  %w( railties actionpack activerecord actionmailer activesupport actionwebservice ).each do |framework|

    paths.each { |path| mkdir_p "#{path}/#{framework}" }

    yield framework

  end

end

restart rails app in switchtower on textdrive

technoweenie (Rick Olson) — Sat, 05 Nov 2005 05:06:56 GMT

You'll have to override the standard Switchtower restart task if you don't have sudo access:

desc "Restart the FCGI processes on the app server."

task :restart, :roles => :app do

  run "ruby #{current_path}/script/process/reaper"

end

Set an ActionController's template root on each request

technoweenie (Rick Olson) — Fri, 04 Nov 2005 15:53:59 GMT

Set an ActionController's template root on each request for a domain acts as account key pattern. Careful with this code though. It relies on the behavior of a private rails method and could change 50 times in the next week. (see my blog post)

class MyController < ActionController::Base

  before_filter :set_site_template_root

  def set_site_template_root

    self.class.template_root = "#{RAILS_ROOT}/#{app}/#{views}/#{current_site.domain}")

    @template.base_path = template_root

  end

end

module ActionView

  class Base

    private

    alias_method :rails_assign_method_name, :assign_method_name



    # add a domain prefix at the end

    def assign_method_name(extension, template, file_name)

      rails_method_name = rails_assign_method_name(extension, template, file_name)

      @@method_names[file_name || template] = respond_to?(:current_site) ?

        "#{rails_method_name}_#{current_site.domain}".intern :

        rails_method_name

    end

  end

end

transparent pngs in IE

technoweenie (Rick Olson) — Thu, 03 Nov 2005 10:47:44 GMT

Keep in mind that the AlphaImageLoader takes a relative path to the HTML page, not the CSS file (which is in contrast to normal css behavior). Absolute positioning causes it to act funky, so I wouldn't recommend it.

* html #blah {

  filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(src='/full/path/to/img.png', sizingMethod='crop');

  background:none;

  cursor:hand; /* only if this is a link */

  position:relative;

}

css opacity in IE

technoweenie (Rick Olson) — Thu, 03 Nov 2005 10:45:06 GMT

opacity:.7; /* css standard */

filter:alpha(opacity=70); /* IE patch */

using map on an array of elements

technoweenie (Rick Olson) — Mon, 10 Oct 2005 00:37:26 GMT

I wanted to use prototype's map function on a listing of elements like:

document.getElementsByTagName('div').map(function(el) {});

Object.extend(String.prototype, {

  tags_in: function(el) {

    nodes = [];

    elems = $(el).getElementsByTagName(this);

    for(var i = 0; i < elems.length; i++)

      nodes.push(elems[i]);

    return nodes;

  }

});

'div'.tags_in(document).map(function(el) {});