更新＃

Question

我试图在嵌套属性表单更新后发送电子邮件通知，但我一直碰到这个错误，我认为是因为我在委员会模型更新数据库中的对象之前发送电子邮件通知因此我获得Property.councils.email的nil，非常感谢任何帮助。

物业邮件程序

class PropertyMailer < ActionMailer::Base
  default from: "myemail@gmail.com"

  def welcome_email(property, tenants, councils)
    @property = property
    @tenants = tenants
    @councils = property.councils
    mail(:to => property.councils.first.email, subject: 'Here are your property details')
  end
end

property.rb

class Property < ActiveRecord::Base

has_many :council_histories
  accepts_nested_attributes_for :council_histories, :reject_if => :send_email


  has_many :councils, through: :council_histories, :foreign_key => :council_id
  accepts_nested_attributes_for :councils

def send_email
    if council_histories.where(council_id_changed?)
      PropertyMailer.welcome_email(self, tenants, councils).deliver
    end
  end
end

更新＃

'属性/构建控制器'嵌套控制器，使用邪恶的向导表单gem，构建一个多步骤表单。

class Properties::BuildController < ApplicationController
  include Wicked::Wizard

   steps :tenant, :meter, :council, :confirmed 

  def show
    @property = Property.find(params[:property_id])
    @tenants = @property.tenants.new(params[:tenant_id])
    @meter = @property.build_meter
    @property.council_histories.build do |council_history| 
    @council = council_history.build_council 
    end
    render_wizard
  end


  def update
    @property = Property.find(params[:property_id])
    params[:property][:status] = step.to_s
    params[:property][:status] = 'active' if step == steps.last
    @property.update_attributes(params[:property])
    render_wizard @property
  end
end

表单视图

<%= simple_form_for @property, url: wizard_path, :method => 'put' do |f|  %>


  <%= f.simple_fields_for :council_histories do |builder| %>
      <%= builder.input :property_id, as: :hidden, input_html: { value: @property.id } %> 
      <%= builder.input :council_id, :collection => Council.all  %>

      <%= builder.submit %>
    <% end %>
<% end %>

Answer 1

正如Marek Lipka所说，property.councils最有可能返回一个空哈希，但这只是故事的一部分。我认为问题出在您的Property模型中，使用此行：

has_many :council_histories
accepts_nested_attributes_for :council_histories, :reject_if => :send_email
                                                   ^^
                                                   This is the problem here

您的原始假设是正确的，我相信您是在:councils关系有机会填充之前尝试发送电子邮件的。顾名思义，:reject_if方法用于在某些情况下丢弃数据（我自己从不使用它，所以不能想到任何好的例子，但我确信有很多）。 Check here for more info

您是否绝对需要在对象保留之前发送电子邮件？如果没有，可能另一种方法是使用ActiveRecord::Callback方法之一，例如after_commit，如下所示：

class Property < ActiveRecord::Base
    after_commit :send_email
    # Remainder of model code....

Answer 2

您的property.councils调用返回空集。

未定义的方法`email'代表nil：NilClass错误

更新＃

2 个答案: