Rails：按类别搜索和筛选书籍

Question

I need some help please. I am building an advanced search feature for my digital library, and I would like to search books by their names or description and then by also filter the search results by the category which the books belongs.

The database is structured this way: Books belongs sub-categories and categories, while sub-categories belongs to the categories only. But I want to filter by categories.

Let's say I have a book named Great Achievers and Great Developers and they belong to the categories Achievers and Developers respectively. I want the search to work this way: when I search using the keyword Great I would see the books Great Achievers and Great Developers , and when I filter by category Achievers I would see only Great Achievers .

Right now my advanced search feature can search for books by their names and descriptions, but cannot filter the books by category in the search results.

This is the code for the book model

class Book < ApplicationRecord
  has_one_attached :upload
  belongs_to :category, required: false
  belongs_to :sub_category, required: false

  def self.search(keywords)
      if keywords
        where("name LIKE ? OR description LIKE ? OR author LIKE ?", "%#{keywords}%", "%#{keywords}%", "%#{keywords}%").order('id DESC')
      else
        order('id DESC') 
      end
    end
end

This is the code for the category model

class Category < ApplicationRecord
  has_many :sub_categories
  has_many :books
end

This is the code for the sub-category model

class SubCategory < ApplicationRecord
  has_many :books
  belongs_to :category, required: false
 end

This is the truncated code for the books controller

class BooksController < ApplicationController
  def index
    @books = Book.search(params[:keywords]).paginate(:page => params[:page], :per_page => 9).order('created_at DESC')
  end

  private
    def set_book
      @book = Book.find(params[:id])
    end

    def book_params
      params.require(:book).permit(:name, :author, :description, :category_id, :sub_category_id, :new_sub_category_name, :upload, :keywords, :deep_keywords)
    end
end

This is the truncated code for the search feature on the books index view

<%= form_tag(books_path, method: :get) do %>
    <%= text_field_tag :keywords, params[:keywords] %>
    <%= collection_select :category, :id, Category.all.order('name ASC'), :id, :name,{include_blank: 'Select Category'} %>
    <%= submit_tag 'Search', name: nil %>
<% end %>

I have attached a screenshot of my console log when a search action is done

Please any form of assistance will be highly appreciated. Thank you.

Answer 1

The best thing is to find the books that are under filter category. Then filter from that books collection based on the search term.

You can modify the books controller code as below.

def index 
if params['category'].blank? or params['category']['id'].blank? 
@books = Book.all 
else 
category = Category.find(params['category']['id']) 
@books = category.books 
end 
@books = @books.search(params[:keywords]).paginate(:page => params[:page], :per_page => 9).order('created_at DESC') 
end

The truncated code for the search feature on the books index view can remain the same

<%= form_tag(books_path, method: :get) do %>
    <%= text_field_tag :keywords, params[:keywords] %>
    <%= collection_select :category, :id, Category.all.order('name ASC'), :id, :name,{include_blank: 'Select Category'} %>
    <%= submit_tag 'Search', name: nil %>
<% end %>

The code for the book model can also remain the same

class Book < ApplicationRecord
  has_one_attached :upload
  belongs_to :category, required: false
  belongs_to :sub_category, required: false

  def self.search(keywords)
      if keywords
        where("name LIKE ? OR description LIKE ? OR author LIKE ?", "%#{keywords}%", "%#{keywords}%", "%#{keywords}%").order('id DESC')
      else
        order('id DESC') 
      end
    end
end

I hope this helps.

Upvote this answer as useful if it helps, or comment below the answer for more clarification.

Answer 2

Searching is something that you can avoid doing on your own if you use ransack . You can even do a one-liner in your controller with it to achieve what you want:

def index
    @books = Book.all.ransack(params[:q]).results.paginate(:page => params[:page], :per_page => 9)
end

Then in your requests you have to pass the params[:q] , doing whatever search you need done for the books resource. IE:

#params[:q] for books with category_id == 10
{ "category_id_eq": 10 }
#params[:q] for books with name or description or author matching "search"
{ "name_or_description_or_author_matches": "%search%" }
#params[:q] for books with name or description or author matching "search" and category_id == 10
{ "name_or_description_or_author_matches": "%search%", "category_id_eq": 10 }
#params[:q] for books with name or description or author matching "search" and category_id == 10, ordered by created_at
{ "name_or_description_or_author_matches": "%search%", "category_id_eq": 10, "s": "created_at desc" }

Check the available matchers so you can build your filters as you wish.

Answer 3

You need a join (untested, but you get the idea):

def self.search(params)
  books = where(nil)
  keywords = params.dig(:keywords)
  if keywords
    books = books.where("name LIKE ? OR description LIKE ? OR author LIKE ?",
                         "%#{keywords}%", "%#{keywords}%", "%#{keywords}%")   
  end

  cat_id = params.dig(:category, :id)
  if cat_id
    books = books.joins(:category).where(category: {id: cat_id})
  end

  books.order('id DESC')
end

EDIT:

  def index
    @books = Book.search(params).
             paginate(page: params[:page], per_page: 9).
             order('created_at DESC') # You already set order on search
  end