SearchModel

The plugin helps to build search forms in your rails application. It allows to have complex search parameters, restful and easily testable controller and clean and standard forms in the view.

It expects that your model has a named scope for every search parameter that you'd like to have. I've figured that using named scopes is convenient for search parameters cause it allows you to encapsulate db specific stuff:

class Post < ActiveRecord::Base has_and_belongs_to_many :categories

named_scope :by_categories, lambda { |categories| { :include => :categories, :conditions => ['categories.id IN (?)', categories] } }

named_scope :by_keyword, lambda { |value| { :conditions => ['(title like ? OR body like ?)', "%#{value}%", "%#{value}%"]
} } end

In this example by_categories named scope allows to search by ids of categories so you could have a list of categories as a bunch of check boxes in your search form.

To make a search form restful I usually create a separate controller for it with new and create actions:

The new action displays a search form and the create action (after the user submits the form) displays the same form with the values entered and the search results.

To make the controller easily testable the plugin provides a SearchModel class that encapsulates all search related logic and which you can subclass to create your own search class:

class PostSearch < SearchModel search_attributes :categories, :keyword end

The search_attribute method is used to define which search parameters you would like to have. There needs to be a named scope for each parameter in the model.

SearchModel provides a constructor that supports mass assignment and creates attributes for every search parameter. That means that it can be used like an ActiveRecord object in the controller:

class PostSearchesController < ApplicationController def new @search = PostSearch.new end

def create @search = PostSearch.new(params[:search]) @posts = @search.results end end

The results method returns records that match the search criteria.

In the view you just build a form as you would do for any ActiveRecord instance:

<% form_for :search, @search do |form| -%>

<%= form.label :keyword %> <%= form.text_field :keyword %>

.... <% end -%>

SearchModel gets all parameters from the request and generated a query using the named scopes for the parameters that are not blank. All logic is in the search object which makes the controller skinny and easily testable. The search object has attributes for every search parameter which makes it easy to display the search form with the parameters entered on the search results page. The fact that it uses named scope for search parameters allows to have any kind of search parameters - just define a named scope for it. It supports search parameters which are arrays (like a group of check boxes) or hashes (like complex attributes which consist of several attributes).

Copyright (c) 2008 Eugene Bolshakov, released under the MIT license