ActiveRecord::MultiConditions

MultiConditions is a simple ActiveRecord plugin for storing ActiveRecord find conditions and make complex queries painless.

*DISCONTINUED PROJECT*: as of April 2009, I decided to discontinue the development of this library to concentrate my efforts on other projects.

If you are looking for a good alternative, I encourage you to have a look at Ben Johnson’s SearchLogic library. SearchLogic provides all ActiveRecord::Multiconditions features along with many other cool stuff.

Overview

This plugin doesn’t replace ActiveRecord#with_scope method, nor the basic :condition usage but extends it with the ability of storing illimitate conditions in multiple step.

  class Task < ActiveRecord::Base; end

  # create a new MultiConditions instance
  conditions = Task.multicondition

  # append a condition
  conditions.append_condition(['active = ? AND query LIKE ?', true, '%foo'])

  # conditional-append a condition
  conditions.append_condition(['name = ?', 'aname']) if admin?

  # get the final condition list ...
  conditions.to_conditions
  # => "active = true AND query LIKE '%foo' AND name = 'aname'"

  # ... compatible with ActiveRecord finders
  Task.find(:all, :conditions => conditions.to_conditions)

Dependencies

• Ruby 1.8.6
• ActiveRecord >= 2.0 (tested up to AR 2.3)

If you want to run the test suite:

• sqlite3-ruby

Download and Installation

Installing ActiveRecord MultiConditions as a GEM is probably the best and easiest way. You must have RubyGems installed for the following instruction to work:

    $ sudo gem install activerecord-multiconditions

To install the library manually grab the source code from the website, navigate to the root library directory and enter:

    $ sudo ruby setup.rb

If you need the latest development version you can download the source code from the GIT repositories listed above. Beware that the code might not as stable as the official release.

Usage

First, don’t forget to require the library.

    require 'rubygems'
    require 'activerecord-multiconditions'

Now MultiConditions object is automatically available as subclass of any ActiveRecord object.

    class Task < ActiveRecord::Base
      # your Task model
    end

    multiconditions = Task.multiconditions(:status => 'active')
    # => new instance

Creating a new instance

If you use ActiveRecord from Rails, this is just a matter of creating a new Model.

    # create the Task model
    class Task < ActiveRecord::Base
    end

Now MultiConditions is automatically available within your Task namespace. You can use it in whatever class method, for example:

    class Task < ActiveRecord::Base

      def complex_search()
        c = multiconditions(:foo => 'bar')
        Task.find(:all, c.to_conditions)
      end

    end

But you can create a new instance from an other library, class or model as well. Just remember to initialize MultiConditions from its own namespace.

    class Foo
      class << self
        def my_cool_conditions
          Task::multiconditions(:foo => 1).to_conditions
        end
      end
    end

    Foo.my_cool_conditions
    # => 'foo = 1'

Appending conditions

You can append new conditions with the following methods, passing the conditions you want to append or prepend as parameters.

• #append_condition
• #prepend_condition

See Condition Types section to lean more about supported objects.

  conditions.append_condition(['active = ? AND query LIKE ?', true, '%foo']
  conditions.prepend_condition(['name = ?', 'aname']

  conditions.to_conditions
  # => "name = 'aname' AND active = true AND query LIKE '%foo'"

Condition types

The MultiConditions object accepts any type of conditions supported by ActiveRecord, including Strings, Arrays and Hashes, and merges them alltogether just before sending the final :condition value to ActiveRecord search method.

  conditions.append_conditions(:foo => 1, :bar => 2)
  conditions.append_conditions('active = 1')
  conditions.append_conditions(['name LIKE ?', '%foo'])

  conditions.to_conditions
  # => 'foo = 1 AND :bar = 2 AND active = 1 AND name LIKE '%foo'

See ActiveRecord::Base#find documentation for more conditions examples.

Important

Once loaded, this library become part of ActiveRecord package and creates its own namespace at ActiveRecord::Base::MultiConditions.

  require 'multi_conditions'

For various reason, you cannot initialize a new ActiveRecord::Base::MultiConditions but you MUST initialize a MultiConditions instance from a Model or using the ActiveRecord::Base#multiconditions method (preferred way).

  # The wrong way
  # raises Message: <"undefined method `abstract_class?' for Object:Class">
  ActiveRecord::Base::MultiConditions.new

  # The right way
  class Model < ActiveRecord::Base
    def a_method()
      c = MultiConditions.new(Model, ['foo = ?', 'bar'])
      find(:all, :conditions => c.to_conditions)
    end
  end

  # The best way
  class Model < ActiveRecord::Base
  end
  conditions = Model.multiconditions(['foo = ?', 'bar'])

Author

• Simone Carletti <weppos@weppos.net>

Resources

• Homepage
• API
• GitHub
• RubyForge

FeedBack and Bug reports

Feel free to email Simone Carletti with any questions or feedback.

Please use the Ticket System to submit bug reports or feature request.

Changelog

See the CHANGELOG.rdoc file for details.

License

Copyright © 2008-2009 Simone Carletti, ActiveRecord::MultiConditions is released under the MIT license.