= has_handle_fallback

Make it easy to use handles (callsigns/monikers/usernames) in URLs, even if they might be blank.

== Quickstart

  class Person < ActiveRecord::Base
    has_handle_fallback :email
  end

This assumes that <tt>Person</tt> has the fields <tt>handle</tt> and <tt>email</tt>.

  class PeopleController < ActionController::Base
    def object
      @object ||= Person.find_by_id_or_handle(params[:id])
    end
  end

Then you can safely use <tt>Person#to_param</tt> in URLs, etc. because, when in doubt, the finder will use the numeric ID.

  Long forms:  Person.find_by_id_or_handle('pierrebourdieu'), Person.find_by_id_or_handle(1)
  Short forms: Person['pierrebourdieu'], Person[1]

== What's going on?

  def test_only_uses_handle_as_param_when_not_changed_from_value_in_database
    pierre = Person.new :email => 'pierre.bourdieu@example.com'
    
    # not saved, so to_param is just blank
    assert_equal '', pierre.to_param
    assert_equal nil, Person[pierre.to_param]
    
    # no handle set, so to_param is integer primary key
    pierre.save!
    assert_equal pierre.id.to_s, pierre.to_param
    assert_equal pierre, Person[pierre.to_param]
    
    # handle is set, but not saved, so STILL use integer primary key
    pierre.handle = 'pierrebourdieu'
    assert_equal pierre.id.to_s, pierre.to_param
    assert_equal pierre, Person[pierre.to_param]
    
    # now handle is saved, so we can use it as the param
    pierre.save!
    assert_equal 'pierrebourdieu', pierre.to_param
    assert_equal pierre, Person[pierre.to_param]
    
    # handle was changed, so let's use the integer primary key until it's saved again
    pierre.handle = ''
    assert_equal pierre.id.to_s, pierre.to_param
    assert_equal pierre, Person[pierre.to_param]
  end

== Copyright

Copyright (c) 2010 Seamus Abshere. See LICENSE for details.