Rails csv与协会的导入

Question

我正在构建一个将应用程序与许多不同类别关联的应用程序。例如，我有一个帖子，需要能够通过csv导入通过rake任务将其分配到体育，新闻和科学类别。

我的问题是如何将多个category_ids的数组导入到Post模型中？我有它的工作，我可以手动创建一个新的职位，并指定多个类别的职位，但我很困惑，如何通过CSV完成。我需要帮助找出实现这一目标的最佳方法。

这是我到目前为止有：

模式

create_table "posts", force: :cascade do |t| 
    t.string "name" 
    t.text  "description" 
    end 

    create_table "styles", force: :cascade do |t| 
    t.datetime "created_at", null: false 
    t.datetime "updated_at", null: false 
    t.integer "post_id" 
    t.integer "category_id" 
    end 

    create_table "categories", force: :cascade do |t| 
    t.string "name" 
    t.datetime "created_at",  null: false 
    t.datetime "updated_at",  null: false 
    end 

Post.rb

class Post < ApplicationRecord 
    has_many :styles 
    has_many :categories, through: :styles 
end 

Category.rb

class Category < ApplicationRecord 
    has_many :styles 
    has_many :posts, through: :styles 
end 

Style.rb

class Style < ApplicationRecord 
    belongs_to :post 
    belongs_to :category 
end 

Rake任务

require 'csv' 
require 'open-uri' 
namespace :post_import do 
    desc "Import posts daily" 
    task posts: :environment do 
    filename = File.join Rails.root, "posts.csv" 
    counter = 0 

    CSV.foreach(filename) do |row| 
     name, category, description = row 
     post = Post.create(name: name, category_ids: category, description: description) 
     counter += 1 if post.persisted? 
    end 

    puts "Imported #{counter} [posts]" 
    end 
end 

Answer 1

我能够从克里斯的帮助，在gorails.com来解决这个问题。这是我的（粗糙的）工作解决方案。希望这可以帮助其他人解决这个问题！

require 'csv' 
require 'open-uri' 
namespace :post_import do 
    desc "Import posts daily" 
    task posts: :environment do 
    filename = File.join Rails.root, "posts.csv" 
    counter = 0 

    CSV.foreach(filename) do |row| 
     name, category_ids, description = row 
     post = Post.new(name: name, description: description) if post == nil 
     post.save 

     #separate string of category ids into array 
     a_categories = category_ids.split(",") 

     a_categories.each do |category_id| 
     post.styles.where(category_id: category_id).first_or_create 
     end 

     counter += 1 if post.persisted? 
    end 

    puts "Imported #{counter} [posts] 
    end 
end 

Answer 2

require 'csv' 
require 'open-uri' 
namespace :post_import do 
    desc "Import posts daily" 
    task posts: :environment do 
    filename = File.join Rails.root, "posts.csv" 
    counter = 0 

    CSV.foreach(filename) do |row| 
     name, category, description = row 

     #you can user find or create, but for clarity I split it 
     post = Post.where(name: name).first 
     post = Post.new(name: name, description: description) if post == nil 

     #now we can simply add the style which joins to the category 
     post.styles.build(category_id: category) 
     post.save 
     counter += 1 if post.persisted? 
    end 

    puts "Imported #{counter} [posts]" 
    end 
end