Cron Job to clear Rails Cache

The rails file cache is something that keeps growing.
Here are some 'handy' snippets.

Delete all files older then 7 days. (replace -delete with -print to test it)

find ./tmp/cache/ -type f -mtime +7 -delete

Delete all empty folders. (mindepth prevents the deletion of the root folder)

find ./tmp/cache/ -type d -empty -delete -mindepth 1

The whenever.rb I use

job_type :command_in_path, "cd :path && :task :output"

every :day, at: "0:40" do
  command_in_path "find ./tmp/cache/ -type f -mtime +7 -delete"

every :day, at: "1:10" do
  command_in_path "find ./tmp/cache/ -type d -empty -delete -mindepth 1"

Rails Email Preview

Just a short post for myself to remember the ActionMailer Preview functionality.


class MailerPreview < ActionMailer::Preview
  def mailer_method_name
    TeamPersonMailer.mailer_method_name( email_method_argument ) 

And view your preview emails at: http://localhost:3000/rails/mailers

Fix rails database collations

Today I discovered my Ruby on Rails development environment database migrated with the wrong character encoding. It was using the MySQL default encoding latin1.
I didn't feel throwing my database away because it contains a lot of stuff.

I used the following snippet to convert all columns to utf8

    ActiveRecord::Base.connection.tables.each do |table|
      ActiveRecord::Base.connection.execute( &quot;ALTER TABLE `#{table}` CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci&quot;)

A copy of has been removed from the module tree but is still active

I'm working on a rails website that requires me to specify a class in an initializer.


spree.searcher_class = MySearcherClass

I'm currently developing this searcher class. Every time I change this class I get the following message:

A copy of MySearcherClass has been removed from the module tree but is still active

This sucks big time! Because I need to restart my rails application every time I change something.

My workaround for the moment is this:

spree.searcher_class = do
    def new(*args,&block)
      return *args, &block )

I'm not very keen on this, but it does the trick for now :)

Ruby on Rails Json Serialization – To Infinity and beyond!

Wel the title says it all :)

There's a subtile, but very important difference between Ruby on Rails 3 and 4 with json serialization.

Rails 3

(1..10).as_json => [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Rails 4

(1..10).as_json => "1..10"

I had a piece of Ruby code that modeled the business rules of the application like this:

  brackets: [
    { income: 0..19_645,               perc: 37 },
    { income: 19_646..55_991,          perc: 42 },
    { income: 55_992..Float::INFINITY, perc: 52 }

Try serializing this to the browser with to_json in Rails 3 and prepare for a long wait ;)

The workaround I used to this was creating an initalizer "/config/initializer/range_to_json_monkey_patch.rb"

# This initializer requires some explanation
# In the ruby version installed (Rails 3.2.13)  the json encoding method works like this:
#   ActiveSupport::JSON::encode(1..10)  => [1,2,3,4,5,6,7,8,9,10]
# Doing this with a large range  is not nice!!
# Ruby on rails works like this:
#   ActiveSupport::JSON::encode(1..10)  => "1..10"
# This initializer modifies the Range#as_json method so it works like rails 4
# this method first checks if this adjustment is required
if (1..4).as_json.kind_of?(Array)

  class Range
    def as_json( options=nil )


Now the json-serialization of Ranges will behave like the one in Rails 4.