我希望用户能够评论其他人的微博，但我不断收到以下错误：无法将 nil 转换为确切的数字
它来自下面 View/comments/_form 文件中的时间戳。出于某种原因，@comment.created_at 以 nil 的形式返回
View/comments/_form:(这个部分在每个微博结束时调用）
<span class="content"><%= @comment.content %></span>
<span class="timestamp">Said <%= time_ago_in_words(@comment.created_at) %> ago.</span
<%= form_for(@comment) do |f| %>
<%= f.text_field :content, placeholder: "Say Something..." if signed_in? %>
<% end %>
用户模型：
attr_accessible :name, :email, :password, :password_confirmation #is this secure with password there?
attr_protected :admin #attr_protected necessary?
has_many :microposts, dependent: :destroy
has_many :comments, :through => :microposts, dependent: :destroy
微贴模型：
attr_accessible :comment #basically the content of the post
attr_protected :user_id
has_many :comments, dependent: :destroy
评论型号：
attr_accessible :content, :micropost
belongs_to :user
belongs_to :micropost
validates :user_id, presence: true
validates :micropost_id, presence: true
validates :content, presence: true
default_scope order: 'comments.created_at ASC' #is this necessary?
评论控制器：
def create
@micropost = Micropost.find_by_id(params[:id]) #is this necessary?
@comment = current_user.comments.create(:micropost => @micropost)
redirect_to :back
end
用户控制器：
def show
@user = User.find_by_id(params[:id])
@microposts = @user.microposts.paginate(page: params[:page])
@micropost = current_user.microposts.build
@comments = @micropost.comments
@comment = current_user.comments.create(:micropost => @micropost) #build, new or create??
end
路线：
resources :users
resources :microposts, only: [:create, :destroy]
resources :comments, only: [:create, :destroy]
SQL：
"comment"=>{"content"=>"EXAMPLE"}} 用户负载 (0.8ms) SELECT "users".* FROM "users" WHERE "users"."remember_token" = 'H09yZpAv5qhmT3ok5fXfnQ' LIMIT 1 Micropost Load (0.7 ms) SELECT "microposts".* FROM "microposts" WHERE "microposts"."id" IS NULL