Building web applications and fighting the daily madness
ActiveRecord loads the xxx_type in your model, making it blow up when doing includes / using the belongs_to on a missing type.
So we make it un-missing.
Usage
class Waldo < MissingType
end
Code
class MissingType < ActiveRecord::Base
default_scope :conditions => "1 = 2", :limit => 0
self.table_name = "schema_migrations"
def self.primary_key
"version"
end
def readonly?
true
end
end
Repeatedly entering password is quiet annoying, luckily most vagrant base boxes come with the same insecure ssh key 
curl https://raw.github.com/mitchellh/vagrant/master/keys/vagrant > vagrant.key chmod 600 vagrant.key knife solo cook --ssh-identity vagrant.key vagrant@vagrant
We want to enqueue jobs, but do not want to blow up the app with sidekiq and it’s dependencies.
Usage
RawSidekiq.enqueue("XyzJob", [1,2,3], :namespace => "custom")
Code
# http://grosser.it/2013/01/17/enqueue-into-sidekiq-via-pure-redis-without-loading-sidekiq
require "json"
require "redis"
require "securerandom"
class RawSidekiq
def self.enqueue(queue, klass, args, options={})
payload = {
'class' => klass,
'args' => args,
'jid' => SecureRandom.hex(12),
#'retry' => true
}.to_json
conn = Redis.new
conn.multi do
conn.sadd([options[:namespace], "queues"].compact.join(":"), queue)
conn.lpush([options[:namespace], "queue", queue].compact.join(":"), payload)
end
end
end
Killing observers
Before:
# config/environment.rb
config.observers = [:foo_observer]
# app/observers/foo_observer.rb
class FooObserver < ActiveRecord::Observer
observes :user
def after_save(user)
....
end
end
After:
# app/models/user.rb
class User < ActiveRecord::Base
include FooObserver
end
# app/observers/foo_observer.rb
module FooObserver
class << self
def included(base)
this = self
base.after_save{|user| this.more_descriptive_name(user) }
end
def more_descriptive_name(user)
...
end
end
end
Normal headers like Accept or :authorization do not work in rails 3 integration tests and you need to convert everything to HTTP_ACCEPT etc, to help find all those places and make sure you do not introduce new bugs in rails 2 add this:
# http://grosser.it/2012/10/19/upgrading-to-rails-3-0-making-sure-you-use-rack-headers-everywhere/
# message can be changed on rails 3, but keep the warning, it's so hard to track down missing headers
# maybe try to remove in rails 3.1+
# can be tested by e.g. changing header to Accept instead of HTTP_ACCEPT
class ActionController::Integration::Session
# headers that are only used by our code and not rails/rack can be whitelisted, but make sure they work on rails 2 and 3
HEADER_WHITELIST = ['Funky-Headers-You-Have-To-Use']
def process_with_header_warning(*args)
if args[3] && bad = args[3].keys.detect{|k| !k.is_a?(String) || (!HEADER_WHITELIST.include?(k) && k !~ /^[A-Z_\d]+$/) }
raise "Header #{bad} will not work on rails 3, please uppercase (Content-Type -> CONTENT_TYPE) and prefix HTTP_ (Accept -> HTTP_ACCEPT)"
end
process_without_header_warning(*args)
end
alias_method_chain :process, :header_warning
end
