A bunch of handy ruby and rails snippets

rails.rb

# This is used in Rails migrations to update ActiveRecord after adding/removing a column from a table
# so that the column can be used in the migration. Doesn't take any arguments, will update the AR
# model that it is called on.
ActiveRecord#reset_column_information

# Reload rails env while in script/console
reload!

# Rails field types
# :type  MySQL type  options
:binary  TINYBLOB, BLOB, MEDIUMBLOB, or LONGBLOB  :limit => 1 to 4294967296 (default = 65536)
:boolean  TINYINT(1)
:date  DATE
:datetime  DATETIME
:decimal  DECIMAL  :precision => 1 to 63 (default = 10), :scale => 0 to 30 (default = 0)
:float  FLOAT
:integer  INT  :limit => 1 to 11 (default = 11)
:primary_key  INT(11) AUTO_INCREMENT PRIMARY KEY
:string  VARCHAR  :limit => 1 to 255 (default = 255)
:text  TINYTEXT, TEXT, MEDIUMTEXT, or LONGTEXT  :limit => 1 to 4294967296 (default = 65536)
:time  TIME
:timestamp  DATETIME

# Rails migrations quick reference
create_table :table_name do |t|
  t.column :name, :type, :options
  t.timestamps # adds created_at and updated_at
end
drop_table :name
rename_table :old, :new
add_column :table, :name, :type, :options
remove_column :table, :name
rename_column :old, :new
change_column :table, :name, :new_type, :options
add_index :table, [:columns], :options
remove_index :table, :index_name

# Run tests with verbose output
rake test TESTOPTS=-v

# Run specific test file, the :units is required or it will try to run other tests too
rake test:units TEST="test/unit/client_test.rb"

ruby.rb

# Use a regex in square brackets to capture
beginning_numbers = "12345gist"[/^\d+/] # => "12345"

# Convert a UNIX timestamp to a Time object ...
Time.at(timestamp)

# ... and vice versa
Time.new(params).to_i