89 lines
2.6 KiB
Text
89 lines
2.6 KiB
Text
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= acts_as_ordered
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If you find this plugin useful, please consider a donation to show your support!
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http://www.paypal.com/cgi-bin/webscr?cmd=_send-money
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Email address: jonathan.viney@gmail.com
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== Instructions
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This plugin gives ActiveRecord models an easy way to find their neighbours in a given order.
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== Resources
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Install
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* script/plugin install http://svn.viney.net.nz/things/rails/plugins/acts_as_ordered
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== Usage
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class Person < ActiveRecord::Base
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acts_as_ordered :order => 'first_name'
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end
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Say you have people with first names of Adam, Jonathan and Robert:
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p = Person.find_by_first_name('Jonathan')
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p.next # Robert
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p.previous # Adam
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p.previous.previous # Adam (does not wrap around to end)
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p.next.next # Robert (does not wrap around to start)
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If you want the next and previous methods to wrap around the ends, use:
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acts_as_ordered :order => 'first_name', :wrap => true
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You can also jump by more than one at a time:
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# Without wrapping (clamps to ends)
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p = Person.find_by_first_name('Jonathan')
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p.next(:number => 2) # Robert
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p.next(:number => 100) # Robert
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p.previous(:number => 100) # Jonathan
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# With wrapping (wraps around ends as many times as you like)
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p = Person.find_by_first_name('Jonathan')
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p.next(:number => 8) # Adam
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p.previous(:number => 17) # Robert
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You can use this to get the next/previous model that matches some condition:
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class Person < ActiveRecord::Base
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acts_as_ordered :condition => proc { |p| p.age > 10 }
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# Or check that a method on the model returns true
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acts_as_ordered :conditions => :male?
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end
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In this case, the next and previous methods will return the closest adjacent object that matches the condition.
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You can use this in a application to be able to quickly browse through people. Eg:
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class PersonController < ApplicationController
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def view_neighbour
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# params[:direction] is passed off the page as 'next' or 'previous'
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@person = Person.find(params[:id]).find_by_direction(params[:direction])
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render :action => 'view'
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end
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# Or alternatively...
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def view_next
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@person = Person.find(params[:id]).next
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render :action => 'view'
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end
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def view_previous
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@person = Person.find(params[:id]).previous
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render :action => 'view'
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end
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end
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Problems, comments, and suggestions all welcome. jonathan.viney@gmail.com
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== Credits
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Atelier Fabien - Support for :scope =>
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Rick Olson - I borrowed some of the testing code from acts_as_versioned
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