Jnewland's Code Snippets

Restore a single table from a large MySQL backup

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

to ruby mysql backup mysqldump restore by jnewland on Nov 28, 2007

open_body_tag

  #creates a body tag uniquely indentifying this page
  #takes an options Hash with two keys:
  #
  #<tt>id</tt>::        string that will be used as the body's ID. defaults to <tt>controller.controller_name.singularize</tt>
  #<tt>classes</tt>::   an Array of class names. defaults to <tt>[params[:action]]</tt>
  #
  #Examples:
  #
  # in HomeController#index:
  #
  # <%= open_body_tag %>
  # => <body id='home' class='index'>
  #
  # <%= open_body_tag(:id => 'foo') %>
  # => <body id='foo' class='index'>
  #
  # <%= open_body_tag(:id => 'foo', :classes => %w(one two)) %>
  # => <body id='foo' class='one two'>
  def open_body_tag(options = { :id => controller.controller_name.singularize, :classes => [params[:action]] })
    "<body id='#{options[:id]}' class='#{options[:classes].join(' ')}'>"
  end

to ruby rails rubyonrails helper by jnewland on Nov 01, 2007

Test Trackback using cURL

I've Googled this about 20 times - documenting it here for convenience.

curl -d url=TRACKBACK_URL -d title=TRACKBACK_TITLE -d blog_name=TRACKBACK_BLOG_NAME -d excerpt=TRACKBACK_EXCERPT URL

A correct response:

<?xml version="1.0" encoding="utf-8"?>
<response>
<error>0</error>
</response>

to curl blog trackback by jnewland on Sep 13, 2007

Rails URL Validation

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

to ruby rails url uri rubyonrails validation by jnewland on Sep 12, 2007

Mofo - Parse Microformats with Ruby

$ 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"]

to ruby gem mofo microformats by jnewland on Mar 30, 2007

RSS Twitter Bot

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.

to ruby rss xml activerecord twitter by jnewland on Mar 22, 2007

Takes a screenshot and a webcam snapshot and emails them to flickr. Requires isightcapture. Hacked up to spy on the Apple repair team as they try to repair my Mac Book Pro's backlight for the second time.

#!/bin/bash
# requires isightcapture http://www.intergalactic.de/hacks.html

# path to save the images
PATH=/Users/default/

# flickr email address
EMAIL="yourflickremail+private@photos.flickr.com"

# tags to attach to each picture uploaded
TAGS="repair_spy"

TIMESTAMP=`/bin/date "+%y%m%d%H%M%S"`
FRIENDLY_TIMESTAMP=`/bin/date "+%Y/%m/%d %H:%M"`

#take pics
/usr/sbin/screencapture -mxC $PATHscreen_$TIMESTAMP.png
/usr/local/bin/isightcapture -t png $PATHisight_$TIMESTAMP.png

#post to flickr
/usr/bin/uuencode $PATHscreen_$TIMESTAMP.png $PATHscreen_$TIMESTAMP.png | /usr/bin/mail -s "Repair Spy Screenshot - $FRIENDLY_TIMESTAMP tags: $TAGS" $EMAIL
/usr/bin/uuencode $PATHisight_$TIMESTAMP.png $PATHisight_$TIMESTAMP.png | /usr/bin/mail -s "Repair Spy iSight Cature - $FRIENDLY_TIMESTAMP tags: $TAGS" $EMAIL

Toss this in your crontab like so, making sure to run it as the user that you provide to the Apple Techs

*/1    *       *       *       *       default /Users/default/repair_spy >& /dev/null

to apple osx bash by jnewland on Feb 26, 2007

Ruby One Time Web Server

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]

to ruby http by jnewland on Feb 07, 2007

Export del.icio.us links to MT Import Format

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

to ruby delicious del.icio.us movabletype by jnewland on Jan 31, 2007

Synchronizing Rails DB Contents via Fixtures

The following rake task will dump the contents of the current environment's database to YAML fixtures. Stick the following in lib/tasks/fixtures.rake:

namespace :db do
  namespace :fixtures do
    
    desc 'Create YAML test fixtures from data in an existing database.  
    Defaults to development database.  Set RAILS_ENV to override.'
    task :dump => :environment do
      sql  = "SELECT * FROM %s"
      skip_tables = ["schema_info"]
      ActiveRecord::Base.establish_connection(:development)
      (ActiveRecord::Base.connection.tables - skip_tables).each do |table_name|
        i = "000"
        File.open("#{RAILS_ROOT}/test/fixtures/#{table_name}.yml", 'w') do |file|
          data = ActiveRecord::Base.connection.select_all(sql % table_name)
          file.write data.inject({}) { |hash, record|
            hash["#{table_name}_#{i.succ!}"] = record
            hash
          }.to_yaml
        end
      end
    end
  end
end

After making changes to the database that you'd like to dump to fixtures:

rake db:fixtures:dump

After checking out updated fixtures from SVN:

rake db:migrate
rake db:fixtures:load

to rails mysql rubyonrails activerecord fixtures by jnewland on Jan 30, 2007 3 Comments

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