ruby-on-rails - 如何在 rails 服务对象中显示 flash 消息

Question

我想将服务对象添加到我的 Controller 中。是否有机会将 flash 消息包含到该服务对象中？

user_stocks_controller

class UserStocksController < ApplicationController
  def create
    @user_stock = UserStocksCreator.new(current_user, params).call
    redirect_to my_portfolio_path
  end
end

服务对象user_stocks_creator

class UserStocksCreator
  def initialize(current_user, params)
    @current_user = current_user
    @params = params[:stock_ticker]
  end

  def call
    stock = Stock.find_by_ticker(params)
    if stock.blank?
      stock = Stock.new_from_lookup(params)
      stock.save
    end
    @user_stock = UserStock.create(user: current_user, stock: stock)
    flash[:success] = "Stock #{@user_stock.stock.name} was successfully added to portfolio"
  end

  private

  attr_accessor :current_user, :params
end

使用这段代码我有一个错误:

undefined local variable or method `flash'

Answer 1

flash 方法仅在 Controller 中可用。当你想在服务对象中设置 flash 时，你需要将 flash 传递给服务对象。

# in the controller
def create
  @user_stock = UserStocksCreator.new(current_user, params, flash).call
  redirect_to my_portfolio_path
end

# in the service
class UserStocksCreator
  def initialize(current_user, params, flash)
    @current_user = current_user
    @params = params[:stock_ticker]
    @flash = flash
  end

  def call
    # unchanged...
  end

  private

  attr_accessor :current_user, :params, :flash
end