我需要制作一个高级搜索系统，但我不懂ruby，我有问题

Question

我正在做一个高级搜索系统，但我没有结果，搜索根本不起作用，我是rails的新手，从未应用过它。

我的型号

class Product < ActiveRecord::Base
    has_attached_file :image, :styles => { :medium => "300x300>", :thumb => "100x100>" }, :default_url => "default.jpg" 
    validates_attachment_content_type :image, :content_type => ["image/jpg", "image/jpeg", "image/png", "image/gif"]
    belongs_to :category
    belongs_to :user

     def self.search(params)
          conditions_query = []
          conditions_value = []
         if params[:title].present? 
            conditions_query << 'title LIKE ?'
            conditions_value << "%#{params[:title]}%"
         end
         if params[:category].present?
           conditions_query << 'category LIKE ?'
           conditions_value << "%#{params[:category]}%"
         end
         if params[:price].present?
           conditions_query << 'price LIKE ?'
           conditions_value << "%#{params[:price]}%"
         end
            conditions = [conditions_query.join(" AND "), conditions_value]
      end
    end       

我的控制器：

class ProductsController < ApplicationController
  before_action :set_product, only: [:show, :edit, :update, :destroy]
  before_action :set_user, only: [:show, :edit, :update, :destroy, :create, :update, :new]

  # GET /products
  # GET /products.json
  def index
    @products = Product.all
    @user = User.all
  end
  # GET /products/1
  # GET /products/1.json
  def show
  end


  # GET /products/new
  def new
    @product = Product.new
  end
  # GET /products/1/edit
  def edit
  end
  # POST /products
  # POST /products.json
  def create
    @product = Product.new(product_params)
    respond_to do |format|
      if @product.save
         @product.update(user_id: params[:user_id])
        format.html { redirect_to user_products_path(@user.id ,params[:product_id]), notice: 'Product was successfully created.' }
        format.json { render 'show', status: :created, location: @product }
      else
        format.html { render :new }
        format.json { render json: @product.errors, status: :unprocessable_entity }
      end
    end
  end
def update
respond_to do |format|
if @product.update(product_params)
  format.html { redirect_to user_product_path, notice: 'Product was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @product.errors, status: :unprocessable_entity }
      end
    end
  end

# PATCH/PUT /products/1
# PATCH/PUT /products/1.json
  # PATCH/PUT /products/1
  # PATCH/PUT /products/1.json


  # DELETE /products/1
  # DELETE /products/1.json
  def destroy
    @product.destroy
    respond_to do |format|
      format.html { redirect_to user_products_url, notice: 'Product was successfully destroyed.' }
      format.json { head :no_content }
    end
  end
  private
    # Use callbacks to share common setup or constraints between actions.
    def set_product
      @product = Product.find(params[:id])
    end
    # Never trust parameters from the scary internet, only allow the white list through.
    def product_params
      params.require(:product).permit(:title, :price, :local, :description, :category_id, :contacts, :image, :user_id)
    end

    def set_user
      @user = User.find(params[:user_id])
    end

end

我的应用程序：

class ApplicationController < ActionController::Base
  # Prevent CSRF attacks by raising an exception.
  # For APIs, you may want to use :null_session instead.
  protect_from_forgery with: :exception
  helper_method :current_user
  helper_method :cate
   def cate
    Category.all
   end
  private
   def current_user
    User.find_by id: session[:user_id] if session[:user_id] if session[:user_id]
   end
end

Answer 1

看起来你走在了正确的轨道上，但搜索方法实际上并不执行任何查询，即使你已经构建了所有条件。对最后一行进行小的调整，你可以得到这样的结果：

def self.search(params)
  conditions_query = []
  conditions_value = []
  if params[:title].present?
    conditions_query << 'title LIKE ?'
    conditions_value << "%#{params[:title]}%"
  end
  if params[:category].present?
    conditions_query << 'category LIKE ?'
    conditions_value << "%#{params[:category]}%"
  end
  if params[:price].present?
    conditions_query << 'price LIKE ?'
    conditions_value << "%#{params[:price]}%"
  end
  where(conditions_query.join(" AND "), *conditions_value)
end

您缺少where，应该将conditions_value数组泼掉。

尽管我认为写这篇文章的更好方法是使用这样的范围：

scope :title_like, -> (title) { where('title LIKE ?', "%#{title}%") if title.present? }
scope :category_like, -> (category) { where('category LIKE ?', "%#{category}%") if category.present? }
scope :price_like, -> (price) { where('price LIKE ?', "%#{price}%") if price.present? }
def self.search(params)
  title_like(params[:title])
    .category_like(params[:category])
    .price_like(params[:price])
end