Rails 4/ ajax - NoMethodError - nil:NilClass 的未定义方法`id' - 将变量传递给 js 模态

Question

我在 Rails 上有一个非常简单的 Ruby 应用程序，前端为 bootstrap 3：我有优惠，每个优惠 has_many 机会。

在每个交易页面上（交易页面的 url 例如 myapp.com/id=1），我想要一个文本 link，上面写着 "view deal's opportunities"单击时，它会在单击 Bootstrap 模态内的内容外观时触发。

我搞混了，因为在这个 Deal 页面上，我使用了名为 "showcase" 的 Deal 控制器操作。但是为了通过 ajax 生成模式，如下所示，我使用了另一个名为 "show_opportunities" 的操作，在其中，应用程序似乎不知道 @deal（因为@deal 是在不同的 Deal 操作中定义的). 我认为问题出在哪里，但我不太确定。

这是我遇到的错误和我的代码：

Completed 404 Not Found in 3ms

ActiveRecord::RecordNotFound - Couldn't find Deal without an ID:
 activerecord (4.2.0) lib/active_record/relation/finder_methods.rb:433:in `find_with_ids'
  activerecord (4.2.0) lib/active_record/relation/finder_methods.rb:71:in `find'
  friendly_id (5.1.0) lib/friendly_id/finder_methods.rb:20:in `find'
  app/controllers/deals_controller.rb:70:in `show_opportunities'

这一行 70 错误是“@deal = Deal.friendly.find(params[:id])”（见下文）

controller/deals_controller.rb (using @Pavan feedback)
    # used so that old urls created for deals redirects to the new ones created
    # indeed with friendly_id, the url is taken from the title :/deals/title
    # but if we edit the deal title to deal/title2, the old url was still    working
    # we need to redirect the old url
    # source - github.com/norman/friendly_id/issues/385
    before_filter :find_deal,
       :only => [  :showcase ]
    before_filter :ensure_canonical_deal_path!,
      :only => [  :showcase ] 

def showcase    
    @deal = Deal.friendly.find(params[:id])   

    respond_to do |format|
      format.html # showcase.html.erb
      format.json { render json: @deal }
    end
end 

def show_opportunities
    @deal = Deal.friendly.find(params[:deal])
    @opportunity = Opportunity.where('deal_id = ? AND deal_type = ?',
                             @deal.id, "high tech").first

    respond_to do |format|
      format.js
    end
end

protected

def find_deal
   @deal = Deal.friendly.find params[:id]
end
def ensure_canonical_deal_path!
   if request.path != deal_page_path(@deal)
        redirect_to deal_page_path(@deal, :format => params[:format]), :status => :moved_permanently
        return false
   end
end

app/views/deals/showcase.html.erb

<% if @deal.present? %>
   this is the beginning
   <%= render 'deals/deal_info_zone', locals:{deal: @deal} %>
   this is the end
<% end %>

views/deals/_deal_info_zone.html.erb

<div id="zoneA">      
  <div style="color:red;padding-top: 150px;">
    <%= link_to "view infos of Opportunities", deal_opportunities_modal_path, deal: @deal, remote: true %>
  </div>
</div>

views/deals/deal_opportunities_modal.js.erb

这是通过 ajax 的模态触发器：views/deals/opportunity_modal。请注意我在这里是如何尝试通过 Deal 但没有成功的，因此行

$('body').append('<%= j render partial: "deals/deal_opportunities_modal", locals:{deal: @deal} %>'); 
$('#myModal').modal('show');

/app/views/deals/_deal_opportunities_modal.html.erb

<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
  <div class="modal-dialog">
    <div class="modal-content">

      <div class="modal-body"> 

          <%= @opportunity.name %> <br/>     

      </div>

    </div>
  </div>
</div>

routes.rb

match '/deals/:id', # this is the Deal page
    to:   'deals#showcase',
    via:  'get',
    as:   :deal_page

match '/opportunity_modal',
    to:   'deals#show_opportunities',
    via:  'get',
    as:   :deal_opportunities_modal

如何进行这项工作？

用 Pavan 反馈编辑了我的问题

解决方案

我终于找到了我的错误：

我做错了：事实上，当我悬停在 link 'view opportunities' 上方时，我可以看到 linking 指向的 url 是 localhost:3000/opportunity_modal。但这是不可能的！我无法将相同的 url 分配给将出现在所有不同交易页面（id=1、id=2、...）中的所有 links 'view opportunities'。

所以我把路线改为：

 match '/deals/:id/opportunity_modal',
 to: 'deals#show_opportunities',
 via: 'get',
 as: :deal_opportunities_modal

而且有效！！！

Answer 1

NoMethodError - undefined method `id' for nil:NilClass

@deal为nil，需要在show_opportunities方法中定义

def show_opportunities
  @deal = Deal.friendly.find(params[:id])
  @opportunity = Opportunity.where('deal_id = ? AND deal_type = ?', @deal.id, "high tech").first
   respond_to do |format|
     format.js
   end
end

更新：

首先，将showcase方法中的deals = Deal.friendly.find(params[:id])改为@deal = Deal.friendly.find(params[:id])。

并将其作为 locals 在 <%= render 'deals/deal_info_zone' %> 中传递，例如

<%= render 'deals/deal_info_zone', locals:{deal: @deal} %>，然后在_deal_info_zone.html.erb

中传给link_to

<div id="zoneA">      
  <div style="color:red;padding-top: 150px;">
    <%= link_to "view infos of Opportunities", deal_opportunities_modal_path, deal: @deal, remote: true %>
  </div>
</div>

最后在 show_opportunities 方法中访问它，如 @deal = Deal.friendly.find(params[:deal])

Rails 4/ ajax - NoMethodError - nil:NilClass 的未定义方法`id' - 将变量传递给 js 模态

Rails 4/ ajax - NoMethodError - undefined method `id' for nil:NilClass - Passing variable to js modal

javascript

ruby

ajax

ruby-on-rails

ruby-on-rails-3