How to model a custom search form in Rails

Often you need to create a search form to filter the rows in a table that corresponds to a specific model.

SearchLogic can be a valid solution but maybe you want to bet on a more customizable alternative.

The solution I propose is to create a Search.rb class that is able to collect the search parameters and to create the “where conditions” to be applied on our find query.

Suppose you want to filter events records defined by an Event.rb model with the following attributes:

name, string
address, string
start_at, datetime
end_at, datetime

The search mask will propose two text fields for name and address and possibly two DatePicker for start_at and end_at.

You may decide to put AND conditions rather than OR conditions or to define intervals based on the presence of one or both date fields.

Let’s now see how to shape our support class Search.rb (eg create app/models/)

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class Search
attr_reader :options

def initialize(model, options)
@model = model
@options = options || {}
end

def name
options[:name]
end

def address
options[:address]
end

def event_date_after
date_from_options(:event_date_after)
end

def event_date_before
date_from_options(:event_date_before)
end

def has_name?
name.present?
end

def has_address?
address.present?
end

def conditions
conditions = []
parameters = []

return nil if options.empty?

if has_name?
conditions << "#{@model.table_name}.name LIKE ?"
parameters << "%#{name}%"
end

if has_address?
conditions << "#{@model.table_name}.address LIKE ?"
parameters << "%#{address}%"
end

if event_date_after
conditions << "#{@model.table_name}.start_at >= ?"
parameters << event_date_after.to_time
end

if event_date_before
conditions << "#{@model.table_name}.end_at <= ?"
parameters << event_date_before.to_time.end_of_day
end

unless conditions.empty?
[conditions.join(" AND "), *parameters]
else
nil
end
end

private

def date_from_options(which)
part = Proc.new { |n| options["#{which}(#{n}i)"] }
y, m, d = part[1], part[2], part[3]
y = Date.today.year if y.blank?
Date.new(y.to_i, m.to_i, d.to_i)
rescue ArgumentError => e
return nil
end

end

Now we can see how to write the controller that will apply the search.

Specifically, I would make a search that responds to the action index of EventsController.

At this point, an URL without parameters (such as http://localhost:3000/events) will call an Event.find(:all), a request with parameters (such http://localhost:3000/events?name=rock+contest) will apply the search.
This requires that our search form responds to the GET method. We will see this aspect in detail later.

The controller code looks like this:

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class EventsController < ApplicationController

def index
@events = []
@search = Search.new(Event, params[:search])
if is_search?
@events = Event.search(@search, :page => params[:page])
else
@events = Event.paginate(:page => params[:page])
end
end

private

def is_search?
@search.conditions
end

end

As you can see, in the case of search, the class method search will be called.
Let’s see how it was defined in the model Event.rb

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class Event < ActiveRecord::Base

def self.search(search, args = {})
self.build_search_hash search, args
self.paginate(:all, @search_hash)
end

private

def self.build_search_hash(search, args = {})
@search_hash = {:conditions => search.conditions,
:page => args[:page],
:per_page => args[:per_page],
:order => 'events.created_at'}
end
end

At this ponit we can code the search form in this way (using formtastic).

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<% semantic_form_for :search, @search, :html => { :method => :get } do |form| %>
<% form.inputs do %>
<% form.inputs do %>
<%= form.input :name, :label => t('search_form.name') %>
<%= form.input :address, :label => t('search_form.address') %>
<%= form.input :event_date_after,
:as => :date,
:label => t('search_form.event_date_after') %>
<%= form.input :event_date_before,
:as => :date,
:label => t('search_form.event_date_before') %>
<% end %>
<% end %>

<% form.buttons do %>
<%= pretty_positive_button t('search') %>
<% end %>
<% end %>

The search method is GET, so it will append search parameters to the url and will invoke the index method of EventsController.

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Tags: rails, ruby, ruby on rails, search

About Stefano

Stefano Mancini is a co-founder of DevInterface.

After graduating in Computer Science, he first specialized in Java/J2EE development by participating in several international projects in the pharmaceutical and banking ambits.

Enthusiast of agile development, like SCRUM for project management and eXtreme Programming for code writing, he then moved to dynamic languages like Ruby and Python.

About DevInterface

We are an information and communication technology agency. Our mission is to provide web application development, design services and communication strategies. We specialize in building web applications with modern and efficient frameworks.

10 Responses to “How to model a custom search form in Rails”

How to model a custom search form in Rails « XP on Rails says:

Monday May 24th, 2010 at 12:13 PM

[...] ORIGINAL POST [...]
Ale says:

Monday May 24th, 2010 at 03:14 PM

nitpicking:

not address.nil? and not address.empty?

better to user

address.present? #returns true unless address is nil, “”, [] or {} (and maybe some other classes have custom implementations as well)

address.blank? # opposite of address.present?

lots of lovely goodness like this in activesupport, worth reading the code for it to find loads of little cool bits like this
Stefano says:

Monday May 24th, 2010 at 05:18 PM

Thanks Ale.

I’ve updated the post with your suggestions.

Sometimes I’m too Java oriented
Stephan Wehner says:

Monday May 24th, 2010 at 09:29 PM

I think it would be good to include validations in your search class. For example,
start date and end date cannot be more than 1 month apart, price has to be positive,
need to choose some option, etc.

Would the Search class need some connection to the Event class? Call it EventSearch, or bind in some other way ?

Stephan
Stefano says:

Monday May 24th, 2010 at 09:52 PM

Hi Stephan.

Of course you can add all validations you need. I didn’t add them to keep the code readable and simpler.

In my project, the Search class is a bit more complex, because it covers not only the Event model but also other 2 models (Artist and LiveClub).
They have some attributes with the same name (name and address for example) so I’ve used the same Search class to build the where conditions (If I search for Artists, the event_date_after and event_date_before will be false).
Then I’ve extracted the search form as a partial and included it in the right template. In this way I can call the index method of the proper controller.

That’s why I didn’t call this class EventSearch but simply Search.
Finally note that I’ve binded the model class in the constructor.
Tweets that mention How to model a custom search form in Rails « DevInterface Blog -- Topsy.com says:

Tuesday May 25th, 2010 at 08:34 AM

[...] This post was mentioned on Twitter by Dev Interface, Stefano Mancini. Stefano Mancini said: How to model a custom search form in Rails http://bit.ly/aOgx0P [...]
Steve says:

Saturday May 29th, 2010 at 07:21 AM

[...] This post was mentioned on Twitter by Dev Interface, Stefano Mancini. Stefano Mancini said: How to model a custom search form in Rails http://bit.ly/aOgx0P [...]
Boris Rorsvort says:

Friday January 7th, 2011 at 10:29 AM

Awesome, just tried it and it works perfectly =)
No need of searchlogic anymore !
Globolus says:

Tuesday June 28th, 2011 at 10:39 PM

Sorry, but how can I get it work under rails 3?
Ratheesh R says:

Wednesday January 25th, 2012 at 06:11 AM

Im new to Ruby on Rails. SO please help me, I have followed the below forum to make a REST api for my app. “http://digg.com/newsbar/topnews/How_to_create_a_REST_API_for_Ruby_on_Rails_applications”.

But the ‘map.connect_resource :book’(mentioned in the 3rd page of the doc) causes the following error, when executes ‘rake test:functionals.

Error: undefined local variable or method `map’ for #.

In my app, Im trying to implement RoR with mysql DB with the following table data. Table Name: Object Fields: object_id, Object_name, Object_description etc…

I would like to create REST api object for querying the above database and retrieving the data as api object…

DevInterface