Question

I have built a blog application w/ ruby on rails and I am trying to implement a search feature. The blog application allows for users to tag posts. The tags are created in their own table and belong_to :post. When a tag is created, so is a record in the tag table where the name of the tag is tag_name and associated by post_id. Tags are strings.

I am trying to allow a user to search for any word tag_name in any order. Here is what I mean. Lets say a particular post has a tag that is ‘ruby code controller’. In my current search feature, that tag will be found if the user searches for ‘ruby’, ‘ruby code’, or ‘ruby code controller’. It will not be found if the user types in ‘ruby controller’.

Essentially what I am saying is that I would like each word entered in the search to be searched for, not necessarily the ‘string’ that is entered into the search.

I have been experimenting with providing multiple textfields to allow the user to type in multiple words, and also have been playing around with the code below, but can’t seem to accomplish the above. I am new to ruby and rails so sorry if this is an obvious question and prior to installing a gem or plugin I thought I would check to see if there was a simple fix. Here is my code:

View: /views/tags/index.html.erb

<% form_tag tags_path, :method => 'get' do %>
    <p>
      <%= text_field_tag :search, params[:search], :class => "textfield-search" %>
      <%= submit_tag "Search", :name => nil, :class => "search-button" %>
    </p>
  <% end %>

TagsController

 def index
    @tags = Tag.search(params[:search]).paginate :page => params[:page], :per_page => 5
    @tagsearch = Tag.search(params[:search])
    @tag_counts = Tag.count(:group => :tag_name, 
       :order => 'count_all DESC', :limit => 100)

    respond_to do |format|
      format.html # index.html.erb
      format.xml  { render :xml => @tags }
    end
  end

Tag Model

class Tag < ActiveRecord::Base
  belongs_to :post
  validates_length_of :tag_name, :maximum=>42
  validates_presence_of :tag_name

  def self.search(search)
    if search
      find(:all, :order => "created_at DESC", :conditions => ['tag_name LIKE ?', "%#{search}%"])
    else
      find(:all, :order => "created_at DESC")
    end
  end

end

Answer 1

If I read your problem correctly, you want to return a row if the tag names for the row matches one of the words passed in the query string.

You can rewrite your search method as follows:

def self.search(search)
  all :conditions =>  (search ? { :tag_name => search.split} : [])
end

If you need partial matching then do the following:

def self.search(str)
  return [] if str.blank?
  cond_text   = str.split.map{|w| "tag_name LIKE ? "}.join(" OR ")
  cond_values = str.split.map{|w| "%#{w}%"}
  all(:conditions =>  (str ? [cond_text, *cond_values] : []))
end

Edit 1
If you want pass multiple search strings then:

def self.search(*args)
  return [] if args.blank?
  cond_text, cond_values = [], []
  args.each do |str|
    next if str.blank?  
    cond_text << "( %s )" % str.split.map{|w| "tag_name LIKE ? "}.join(" OR ")
    cond_values.concat(str.split.map{|w| "%#{w}%"})
  end
  all :conditions =>  [cond_text.join(" AND "), *cond_values]
end

Now you can make calls such as:

Tag.search("Ruby On Rails")

Tag.search("Ruby On Rails", "Houston")

Tag.search("Ruby On Rails", "Houston", "TX")

Tag.search("Ruby On Rails", "Houston", "TX", "Blah")

Tag.search("Ruby On Rails", "Houston", "TX", "Blah", ....) # n parameters

Caveat:

The wild card LIKE searches are not very efficient(as they don’t use the index). You should consider using Sphinx (via ThinkingSphinx) OR Solr(via SunSpot) if you have lot of data.