DZone Snippets: ruby code

Restore a single table from a large MySQL backup

jnewland (Jesse Newland) — Wed, 28 Nov 2007 14:10:03 GMT

Say, for some reason, you need to restore the entire contents of a single table from a HUGE mysqldump generated backup containing several tables. For example:



create table `baz`;



GIGS OF SQL YOU DON'T WANT;



create table `foo`;



A COUPLE THOUSAND LINES YOU DO WANT;



create table `bar`;



MORE SQL YOU DON'T WANT;

With a little dash 'o ruby, you can extract just the part you want:



$ ruby -ne '@found=true if $_ =~ /^CREATE TABLE `foo`/i; next unless @found; exit if $_ =~ /^CREATE TABLE (?!`foo`)/i; puts $_;' giant_sql_dump.sql > foo.sql

$ cat foo.sql

create table `foo`;



A COUPLE THOUSAND LINES YOU DO WANT;

You can then easily restore that entire table:



$ mysql mydatabase -e 'drop table foo'

$ mysql mydatabase < foo.sql

open_body_tag

jnewland (Jesse Newland) — Thu, 01 Nov 2007 19:24:01 GMT



  #creates a body tag uniquely indentifying this page

  #takes an options Hash with two keys:

  #

  #id::        string that will be used as the body's ID. defaults to controller.controller_name.singularize

  #classes::   an Array of class names. defaults to [params[:action]]

  #

  #Examples:

  #

  # in HomeController#index:

  #

  # <%= open_body_tag %>

  # => 

  #

  # <%= open_body_tag(:id => 'foo') %>

  # => 

  #

  # <%= open_body_tag(:id => 'foo', :classes => %w(one two)) %>

  # => 

  def open_body_tag(options = { :id => controller.controller_name.singularize, :classes => [params[:action]] })

    ""

  end

Rails URL Validation

jnewland (Jesse Newland) — Wed, 12 Sep 2007 14:03:00 GMT

No regexes, allows URLs with ports or IPs. Inspiration from here



  validates_each :href, :on => :create do |record, attr, value|

    begin

      uri = URI.parse(value)

      if uri.class != URI::HTTP

        record.errors.add(attr, 'Only HTTP protocol addresses can be used')

      end

    rescue URI::InvalidURIError

      record.errors.add(attr, 'The format of the url is not valid.')

    end

  end

Mofo - Parse Microformats with Ruby

jnewland (Jesse Newland) — Fri, 30 Mar 2007 16:58:34 GMT



$ sudo gem install mofo 

Successfully installed mofo-0.2.1

$ irb -rubygems

>> require 'mofo'

=> true

>> HResume.find("http://resume.jnewland.com").tags.uniq.sort

=> ["AJAX", "Apache", "CSS", "Capistrano", "DNS", "GNU/Linux", "HTML", "Javascript", "LAMP", "Mongrel", "Movable Type", "MySQL", "PHP", "Perl", "REST", "RSS", "Ruby", "Ruby on Rails", "SEO", "XHTML", "XML", "XSLT", "high availability", "lighttpd", "load-balanced"]

RSS Twitter Bot

jnewland (Jesse Newland) — Thu, 22 Mar 2007 04:20:12 GMT

Republish an RSS feed on a twitter account. This was the source I used to run the Woot Twitter Bot before they took it over.



require 'rubygems'

require 'active_record'

require 'simple-rss'

require 'open-uri'

require 'twitter'



#twitter account to post to

twitter_email = "yourtwitteremail@bla.com"

twitter_password = "secret"



#rss feed to post

rss_url = "http://yoursite.com/index.xml"

rss_user_agent = "http://twitter.com/yourbot"



#sqlite db

path_to_sqlite_db = "/PATH/TO/db.sqlite"





ActiveRecord::Base.logger = Logger.new(STDERR)

ActiveRecord::Base.colorize_logging = false



ActiveRecord::Base.establish_connection(

    :adapter => "sqlite3",

    :dbfile  => path_to_sqlite_db

)



#uncomment this section the first time to create the table

#

#ActiveRecord::Schema.define do

#    create_table :item do |table|

#        table.column :title, :string

#        table.column :link, :string

#    end

#end



class Item < ActiveRecord::Base

  def to_s

    "#{self.title[0..(130-self.link.length)]} - #{self.link}"

  end

end



#run the beast

rss_items = SimpleRSS.parse open(rss_url ,"User-Agent" => rss_user_agent)



for item in rss_items.items

  Item.transaction do

    unless existing_item = Item.find(:all, :conditions => ["link=?", item.link]).first

      twitter ||= Twitter::Base.new(twitter_email, twitter_password)

      new_item = Item.create(:title => item.title, :link => item.link) 

      twitter.post(new_item.to_s)

    end

  end

end

Run this once with the lines uncommented to create the DB, then slap it in your crontab.

Ruby One Time Web Server

jnewland (Jesse Newland) — Wed, 07 Feb 2007 23:45:38 GMT

An interpretation of OneTimeWebServer in Ruby. OneTimeWebServer holds a single "page" in memory, serves it to the first visitor, and evaporates. Useful for all sorts of hijinks.



#!/usr/local/bin/ruby

require 'socket'

t = STDIN.read

while s = TCPServer.new('127.0.0.1', (ARGV[0] or 8080)).accept

  puts s.gets

  s.print "HTTP/1.1 200/OK\rContent-type: text/plain\r\n\r\n" + t

  s.close

  exit

end

Usage:



echo "test" | ./otws.rb [optional port number, defaults to 8080]

Or for recursive fun:



cat otws.rb | ./otws.rb [optional port number, defaults to 8080]

Export del.icio.us links to MT Import Format

jnewland (Jesse Newland) — Wed, 31 Jan 2007 18:36:51 GMT

A friend of mine needed his del.icio.us links in MT Import format for some reason. This solved that problem.



require 'rexml/document'

require 'net/https'

require 'rubygems'



# change credentials!

user = 'username'

pass = 'password'



# User-Agent: required for del.icio.us api

agent = 'delicious-mt'

xml = ''



http = Net::HTTP.new('api.del.icio.us', 443)

http.use_ssl = true

http.start do |http|

  request = Net::HTTP::Get.new('/v1/posts/all', {'User-Agent' => agent})

  request.basic_auth(user, pass)

  response = http.request(request)

  response.value

  xml = response.body

end

 

REXML::Document.new(xml).elements.each('posts/post') do |el|

  puts "TITLE: #{el.attributes['description']}"

  puts "AUTHOR: Author Name"

  puts "DATE: #{DateTime.parse(el.attributes['time']).strftime("%m/%d/%Y %H:%M:%S")}"

  puts "-----"

  puts "BODY:"

  puts el.attributes['extended']

  puts "-----"

  puts "EXCERPT:"

  puts el.attributes['href']

  puts "KEYWORDS:"

  puts el.attributes['tag']

  puts "-----"

  puts "--------"

end

Capistrano : apply local patches when deploying from an external source code repository

jnewland (Jesse Newland) — Wed, 13 Dec 2006 20:51:35 GMT

I've submitted patches to a couple rails apps, and want to run off of their SCM's trunk code, but with my local patches applied. These Capistrano tasks will take any files matching

patches/*.diff

in your local directory, and apply them before restarting your app.



task :after_setup do

  patches_setup

end



task :after_update_code do

  send_and_apply_patches

end



task :patches_setup do

  run "mkdir -p #{deploy_to}/#{shared_dir}/patches" 

end



task :send_and_apply_patches do

  Dir[File.join(File.dirname(__FILE__), '../patches/*.diff')].sort.each do |patch|

    puts "sending #{File.basename(patch)}"

    put(File.read(patch),

       "#{deploy_to}/#{shared_dir}/patches/#{File.basename(patch)}",

       :mode => 0777)

    puts "applying #{File.basename(patch)}"

    run "cd #{release_path}; patch -p0 < #{deploy_to}/#{shared_dir}/patches/#{File.basename(patch)}"

  end

end

redirect or render

jnewland (Jesse Newland) — Fri, 03 Mar 2006 08:04:07 GMT

Quick method to help your XHR requests degrade gracefully - via the caboo.se



def redirect_or_render( redirect_to_hash, render_page  )  

  if @request.xhr?

    render(render_page)

  else

    redirect_to(redirect_to_hash)

  end

end

Use like this:



redirect_or_render(  

  {:action=>'foo'},

  { :partial => 'monkey', :locals => { :obj = > 'x' } }

)