0

我有点困惑为什么当用户“关注”另一个人时代码工作得很好，但是当用户没有关注任何人时它会抛出下面的错误。

错误：

NoMethodError in Static_pages#home 
undefined method `post' for nil:NilClass

控制器

class StaticPagesController < ApplicationController
  def home
    if signed_in?
      @post = current_user.posts.build
      @activities = PublicActivity::Activity.order("created_at desc").paginate(page: params[:page]) 
      @feed_items = current_user.feed.paginate(page: params[:page]) 
      @items =  (@feed_items + @activities)
      @items.sort_by! {|item| -item.created_at.to_i}
     else
    redirect_to root_path  
    end
  end

当我尝试在视图中使用它时出现错误（views\shared\_items.html.erb）

<%= link_to item.trackable.post.user.name, item.trackable.post.user %>

正如我所提到的，当用户“关注”其他用户时，它可以正常工作

我应该在哪里寻找这样的错误？我试图弄清楚为什么如果用户没有关注任何人，则会引发此错误。

这是完整的跟踪

app/views/shared/_item.html.erb:9:in `_app_views_shared__item_html_erb___832826646_61919064'
actionpack (3.2.3) lib/action_view/template.rb:143:in `block in render'
activesupport (3.2.3) lib/active_support/notifications.rb:125:in `instrument'
actionpack (3.2.3) lib/action_view/template.rb:141:in `render'
actionpack (3.2.3) lib/action_view/renderer/partial_renderer.rb:351:in `block in collection_with_template'
actionpack (3.2.3) lib/action_view/renderer/partial_renderer.rb:348:in `each'
actionpack (3.2.3) lib/action_view/renderer/partial_renderer.rb:348:in `collection_with_template'
actionpack (3.2.3) lib/action_view/renderer/partial_renderer.rb:250:in `render_collection'
actionpack (3.2.3) lib/action_view/renderer/partial_renderer.rb:234:in `block in render'
actionpack (3.2.3) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument'
activesupport (3.2.3) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.3) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.3) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.3) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument'
actionpack (3.2.3) lib/action_view/renderer/partial_renderer.rb:233:in `render'
actionpack (3.2.3) lib/action_view/renderer/renderer.rb:41:in `render_partial'
actionpack (3.2.3) lib/action_view/renderer/renderer.rb:15:in `render'
actionpack (3.2.3) lib/action_view/helpers/rendering_helper.rb:24:in `render'
app/views/shared/_feed.html.erb:5:in `_app_views_shared__feed_html_erb__744481885_62482392'
actionpack (3.2.3) lib/action_view/template.rb:143:in `block in render'
activesupport (3.2.3) lib/active_support/notifications.rb:125:in `instrument'
actionpack (3.2.3) lib/action_view/template.rb:141:in `render'
actionpack (3.2.3) lib/action_view/renderer/partial_renderer.rb:265:in `render_partial'
actionpack (3.2.3) lib/action_view/renderer/partial_renderer.rb:238:in `block in render'
actionpack (3.2.3) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument'
activesupport (3.2.3) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.3) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.3) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.3) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument'
actionpack (3.2.3) lib/action_view/renderer/partial_renderer.rb:237:in `render'
actionpack (3.2.3) lib/action_view/renderer/renderer.rb:41:in `render_partial'
actionpack (3.2.3) lib/action_view/helpers/rendering_helper.rb:27:in `render'
app/views/static_pages/home.html.erb:38:in `_app_views_static_pages_home_html_erb___504558116_37464468'
actionpack (3.2.3) lib/action_view/template.rb:143:in `block in render'
activesupport (3.2.3) lib/active_support/notifications.rb:125:in `instrument'
actionpack (3.2.3) lib/action_view/template.rb:141:in `render'
actionpack (3.2.3) lib/action_view/renderer/template_renderer.rb:47:in `block (2 levels) in render_template'
actionpack (3.2.3) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument'
activesupport (3.2.3) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.3) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.3) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.3) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument'
actionpack (3.2.3) lib/action_view/renderer/template_renderer.rb:46:in `block in render_template'
actionpack (3.2.3) lib/action_view/renderer/template_renderer.rb:54:in `render_with_layout'
actionpack (3.2.3) lib/action_view/renderer/template_renderer.rb:45:in `render_template'
actionpack (3.2.3) lib/action_view/renderer/template_renderer.rb:18:in `render'
actionpack (3.2.3) lib/action_view/renderer/renderer.rb:36:in `render_template'
actionpack (3.2.3) lib/action_view/renderer/renderer.rb:17:in `render'
actionpack (3.2.3) lib/abstract_controller/rendering.rb:110:in `_render_template'
actionpack (3.2.3) lib/action_controller/metal/streaming.rb:225:in `_render_template'
actionpack (3.2.3) lib/abstract_controller/rendering.rb:103:in `render_to_body'
actionpack (3.2.3) lib/action_controller/metal/renderers.rb:28:in `render_to_body'
actionpack (3.2.3) lib/action_controller/metal/compatibility.rb:50:in `render_to_body'
actionpack (3.2.3) lib/abstract_controller/rendering.rb:88:in `render'
actionpack (3.2.3) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:40:in `block (2 levels) in render'
activesupport (3.2.3) lib/active_support/core_ext/benchmark.rb:5:in `block in ms'
C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/benchmark.rb:295:in `realtime'
activesupport (3.2.3) lib/active_support/core_ext/benchmark.rb:5:in `ms'
actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:40:in `block in render'
actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:83:in `cleanup_view_runtime'
activerecord (3.2.3) lib/active_record/railties/controller_runtime.rb:24:in `cleanup_view_runtime'
sunspot_rails (2.0.0) lib/sunspot/rails/railties/controller_runtime.rb:15:in `cleanup_view_runtime'
actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:39:in `render'
actionpack (3.2.3) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (3.2.3) lib/action_controller/metal/implicit_render.rb:5:in `send_action'
actionpack (3.2.3) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.2.3) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.2.3) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.2.3) lib/active_support/callbacks.rb:436:in `_run__762502449__process_action__639804392__callbacks'
activesupport (3.2.3) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.3) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
activesupport (3.2.3) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.3) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.2.3) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.2.3) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.3) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.3) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.2.3) lib/action_controller/metal/params_wrapper.rb:205:in `process_action'
activerecord (3.2.3) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.2.3) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.2.3) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.2.3) lib/action_controller/metal.rb:203:in `dispatch'
actionpack (3.2.3) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.2.3) lib/action_controller/metal.rb:246:in `block in action'
actionpack (3.2.3) lib/action_dispatch/routing/route_set.rb:73:in `call'
actionpack (3.2.3) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
actionpack (3.2.3) lib/action_dispatch/routing/route_set.rb:36:in `call'
journey (1.0.4) lib/journey/router.rb:68:in `block in call'
journey (1.0.4) lib/journey/router.rb:56:in `each'
journey (1.0.4) lib/journey/router.rb:56:in `call'
actionpack (3.2.3) lib/action_dispatch/routing/route_set.rb:600:in `call'
omniauth (1.1.4) lib/omniauth/strategy.rb:184:in `call!'
omniauth (1.1.4) lib/omniauth/strategy.rb:164:in `call'
omniauth (1.1.4) lib/omniauth/builder.rb:49:in `call'
warden (1.2.1) lib/warden/manager.rb:35:in `block in call'
warden (1.2.1) lib/warden/manager.rb:34:in `catch'
warden (1.2.1) lib/warden/manager.rb:34:in `call'
actionpack (3.2.3) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.4.5) lib/rack/etag.rb:23:in `call'
rack (1.4.5) lib/rack/conditionalget.rb:25:in `call'
actionpack (3.2.3) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.2.3) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.2.3) lib/action_dispatch/middleware/flash.rb:242:in `call'
rack (1.4.5) lib/rack/session/abstract/id.rb:210:in `context'
rack (1.4.5) lib/rack/session/abstract/id.rb:205:in `call'
actionpack (3.2.3) lib/action_dispatch/middleware/cookies.rb:338:in `call'
activerecord (3.2.3) lib/active_record/query_cache.rb:64:in `call'
activerecord (3.2.3) lib/active_record/connection_adapters/abstract/connection_pool.rb:467:in `call'
actionpack (3.2.3) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
activesupport (3.2.3) lib/active_support/callbacks.rb:405:in `_run__802127317__call__351719387__callbacks'
activesupport (3.2.3) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.3) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
activesupport (3.2.3) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.3) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (3.2.3) lib/action_dispatch/middleware/reloader.rb:65:in `call'
actionpack (3.2.3) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
actionpack (3.2.3) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
actionpack (3.2.3) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
railties (3.2.3) lib/rails/rack/logger.rb:26:in `call_app'
railties (3.2.3) lib/rails/rack/logger.rb:16:in `call'
actionpack (3.2.3) lib/action_dispatch/middleware/request_id.rb:22:in `call'
rack (1.4.5) lib/rack/methodoverride.rb:21:in `call'
rack (1.4.5) lib/rack/runtime.rb:17:in `call'
activesupport (3.2.3) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.4.5) lib/rack/lock.rb:15:in `call'
actionpack (3.2.3) lib/action_dispatch/middleware/static.rb:62:in `call'
railties (3.2.3) lib/rails/engine.rb:479:in `call'
railties (3.2.3) lib/rails/application.rb:220:in `call'
rack (1.4.5) lib/rack/content_length.rb:14:in `call'
railties (3.2.3) lib/rails/rack/log_tailer.rb:14:in `call'
rack (1.4.5) lib/rack/handler/webrick.rb:59:in `service'
C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'

这是视图的整体结构（错误是由最后的代码引起的）

<% if @feed_items.any? %>

<% if item.class == PublicActivity::Activity %>
   <% if item.trackable_type == "Post" %>
      <%= link_to item.owner.name, item.owner if item.owner %><span class="textname"> posted </span><span class="timestamp"> <%= time_ago_in_words(item.created_at) %> ago.</span>
  <% else %>
   <%= link_to item.owner.name, item.owner if item.owner %><span class="textname"> made a comment </span><span class="timestamp"> <%= time_ago_in_words(item.created_at) %> ago.</span>
  <% end %>
<% else %>
<br>
     <%= link_to item.user.name, item.user %>
      <span class="textname">shared this</span><span class="timestamp"> <%= time_ago_in_words(item.created_at) %> ago.</span>
    <% end %>
<% else %>
<% if item.trackable_type == "Post" %>
  <%= link_to item.owner.name, item.owner if item.owner %><span class="textname"> posted </span><span class="timestamp"> <%= time_ago_in_words(item.created_at) %> ago.
  </span>
  <% else %>
   <%= link_to item.owner.name, item.owner if item.owner %></span><span class="textname"> made a comment on <%= link_to item.trackable.post.user.name, item.trackable.post.user %> </span><span class="timestamp"> <%= time_ago_in_words(item.created_at) %> ago.</span>
  <% end %>
4

1 回答 1

0

如果您的用户没有关注任何内容，我认为trackable是零。如果trackable是 nil，那么它不能有post.

您可能需要添加可追踪检查；

if item.trackable.present?
  -- your code here --
else
  -- perhaps a message that nothing is tracked? --
于 2013-05-03T20:40:05.530 回答