我对 Rails 很陌生，我有一个基于论坛怪物的简单论坛应用程序。我目前正在将它从 rails 3.0.9 更新到 3.2.11。在解决了这个自我造成的问题后，我遇到了另一个问题。
似乎当我尝试显示一个主题时，用户（来自 post.user）对象不应该是 nil。
这是错误
Extracted source (around line #17):
14: <% @topic.posts.each do |post| %>
15: <tr>
16: <td class="post_author" rowspan="2">
17: <span class="name"><%= post.user.username %></span>
18: <span class="avatar"><%= image_tag post.user.gravatar_url %></span>
19: <span class="info smaller">
20: <p><strong><%= "Administrator" if post.user.admin? %></strong></p>
这是我的观点 app/views/topics/show.html.erb
<div class="right controls"><%= link_to "Back to Forum", forum_path(@topic.forum) %></div>
<div class="module">
<div class="module_header">
<%= @topic.title %>
<span class="right controls">
<%= link_to "Edit", edit_topic_path(@topic) if can? :manage, @topic %>
<%= link_to "Delete", @topic, :confirm => "Are you sure?", :method => :delete if can? :manage, @topic %>
<%= link_to @topic.sticky ? "Unstick" : "Sticky", {:controller => 'topics', :action => 'update', :topic => {:sticky => @topic.sticky ? "false" : "true" }}, :method => :put if can? :moderate, @topic %>
<%= link_to @topic.locked ? "Unlock" : "Lock", {:controller => 'topics', :action => 'update', :topic => {:locked => @topic.locked ? "false" : "true" }}, :method => :put if can? :moderate, @topic %>
</span>
</div>
<div>
<table>
<% @topic.posts.each do |post| %>
<tr>
<td class="post_author" rowspan="2">
<span class="name"><%= post.user.username %></span>
<span class="avatar"><%= image_tag post.user.gravatar_url %></span>
<span class="info smaller">
<p><strong><%= "Administrator" if post.user.admin? %></strong></p>
Posts <%= post.user.posts.size %><br />
Registered <%=l post.user.created_at %><br />
</span>
</td>
<td class="post_header">
<span class="left post_date smaller">Posted <%=l post.created_at %></span>
<span class="right controls">
<%= link_to "Reply", new_topic_post_path(@topic) if can? :create, @topic.posts.new %>
<%= link_to "Quote", new_topic_post_path(@topic, :quote => post) if can? :create, @topic.posts.new %>
<%= link_to "Edit", edit_post_path(post) if can? :update, post %>
<%= link_to "Delete", post, :confirm => "Are you sure?", :method => :delete if can? :destroy, post %>
</span>
</td>
</tr>
<tr>
<td class="post_body">
<%= post.body.bbcode_to_html().html_safe %>
</td>
</tr>
<% end %>
</table>
</div>
</div>
<div class="right controls"><p><%= link_to "Back to Forum", forum_path(@topic.forum) %></p></div>
这是控制器 app/controlers/topics_controller.rb
class TopicsController < ApplicationController
load_and_authorize_resource :forum
load_and_authorize_resource :topic, :through => :forum, :shallow => true
def show
@topic.hit! if @topic
end
def create
@topic.user ||= current_user
if @topic.save
flash[:notice] = "Topic was successfully created."
redirect_to topic_url(@topic)
else
render :action => 'new'
end
end
def update
if @topic.update_attributes(params[:topic])
flash[:notice] = "Topic was updated successfully."
redirect_to topic_url(@topic)
end
end
def destroy
if @topic.destroy
flash[:notice] = "Topic was deleted successfully."
redirect_to forum_url(@topic.forum)
end
end
end
Rails 控制台输出确认视图中的代码应该可以工作，并且帖子确实有用户。
ricky ~/forum $ rails c
Loading development environment (Rails 3.2.11)
irb(main):001:0> Topic.find(1).posts.each do |p|
irb(main):002:1* puts p.user.username
irb(main):003:1> end
Topic Load (0.5ms) SELECT `topics`.* FROM `topics` WHERE `topics`.`id` = 1 ORDER BY sticky DESC, updated_at DESC LIMIT 1
Post Load (0.4ms) SELECT `posts`.* FROM `posts` WHERE `posts`.`topic_id` = 1 ORDER BY created_at ASC
User Load (0.5ms) SELECT `users`.* FROM `users` WHERE `users`.`id` = 1 LIMIT 1
admin
=> [#<Post id: 1, body: "Forum Monster is a simple forum generator written i...", forum_id: 1, topic_id: 1, user_id: 1, created_at: "2013-01-19 06:57:23", updated_at: "2013-01-19 06:57:23">]
irb(main):004:0>
我想我可能需要为 cancan can :read User 添加一个功能，但我不太确定。
在此先感谢您帮助这个困惑的 android 开发人员 0.o
编辑
在这里查看完整的源代码
正如您在下面看到的那样，post 模型确实验证了用户的存在
应用程序/模型/post.rb
class Post < ActiveRecord::Base
# Associations
belongs_to :forum, :counter_cache => true
belongs_to :topic, :counter_cache => true, :touch => true
belongs_to :user, :class_name => "User", :counter_cache => true
# Accessors
attr_accessible :body
# Validations
validates :body, :presence => true
validates :user, :presence => true
# Default Scope
default_scope :order => 'created_at ASC'
# Scope to display only the last n posts. Used for "Recent Posts" display
scope :recent, lambda {
|c| reorder('created_at desc').limit(c)
}
# Callbacks
before_save :topic_locked?
# Methods
private
def topic_locked?
if topic.locked?
errors.add(:base, "That topic is locked")
false
end
end
end
是什么让我知道在已播种的数据库中仅存在 1 个帖子，并且它是通过
@current_user = User.find_by_username("admin")
@current_user.topics.create!(...)