Rails：将数据从一个控制器中的实例变量传递到另一个控制器中的实例变量

Question

I have a Rails app which has 2 databases.

1. Legacy DB with table called : Businesses
2. regular development DB that comes with the rails app.

I have data in the Businesses table that I want to put into the development DB. To accomplish this I have taken the following steps:

1. Set up the app so that I can read from the Businesses DB and see the output in the browser. I accomplished this by creating a model Business and a BusinessesController class which reads all the data from the businesses table and stores the entries in an instance variable @businesses

2. Then I created a model called Listing and a ListingsController . I would like to read all the entries from @businesses in the BusinessesController and store them in @listings in the ListingsController .

Thus essentially all I need to do is take data stored in one instance variable and save it in another instance variable. I'm not sure how to do this in Rails.

So far I have the following classes:

Buisiness

class Business < ActiveRecord::Base  
  establish_connection "Listings_development"
end

class BusinessesController < ApplicationController
  def get_all
    @businesses = Business.all
  end

  def index
    self.get_all
    respond_to do |format|
      format.html #index.html.erb
    end
  end
end

index.html.erb

<h1>Listing businesses</h1>

<table>
  <tr>
    <th>Index</th>
    <th>Name</th>
    <th>Phone Number</th>
    <th>Suite</th>
    <th>Address</th>
    <th>City</th>
    <th>Province</th>
    <th>Postal Code</th>
    <th>Fax</th>
    <th>Latitude</th>
    <th>Longitude</th>
    <th>Website</th>
  </tr>

  <% count = 0 %>
  <% @businesses.each do |business| %>
  <!--<%=business.inspect %> <br> <br>-->
  <%count = count.to_i + 1 %> 
  <tr>
    <td><%= business.bid %></td>
    <td><%= business.company_name %></td>
    <td><%= business.phone_number %></td>
    <td><%= business.suite_number %></td>
    <td><%= business.address %></td>
    <td><%= business.city %></td>
    <td><%= business.province %></td>
    <td><%= business.postal_code %></td>
    <td><%= business.fax_number %></td>
    <td><%= business.latitude %></td>
    <td><%= business.longitude %></td>
    <td><%= business.website %></td>    
  <% end %>
</table>

<br />
<%= link_to 'New Business', new_business_path %>

Listings

class Listing < ActiveRecord::Base
  attr_accessor :name, :telephone

  def initialize(attributes = {})
    @name = attributes[:name]
    @telephone = attributes[:telephone]
    @latitude = attributes[:latitude]
    @longitude = attributes[:longitude]

    puts 'Created a new Listing'
  end
end

class ListingsController < ApplicationController
  def get_all
    @listings = @businesses
    # @listings = businesses_controller.get_all
  end

  def index   
    self.get_all

    respond_to do |format|
      format.html #index.html.erb
    end
  end
end

index.html.erb

<h1>Listings</h1>

<p>This is where all Listings will show up</p>
<%= @listings.inspect %> <br/>
<%= @businesses.inspect %>

When I go to url

http://localhost:3000/businesses

I can see the table of all the entries in my legacy DB - businesses table in the browser

But when I go to url:

http://localhost:3000/listings

I just see the place holder text and for values of @businesses & @listings I see nil .

So clearly the @businesses variable is not accessible within the ListingsController class. I'm wondering how to best pass data between these 2 controllers.

Answer 1

You are doing it wrong! You never should need a controller to talk to another controller in a MVC pattern. Your model should be the only responsible to know how to get the data, and so you would use that model in both controllers. Business logic lives at models.

You should use Business model inside Listings controller

@listings = Business.all