我可以删除分配给每个用户的链接，除非他们被投票。如果链接上有任何投票，则调用的删除方法不再有效。
这是在heroku上部署的网站的链接。如果您注册。提交链接，向上或向下投票然后尝试删除您将看到我遇到的错误。
https://salty-eyrie-2549.herokuapp.com/
编辑：启动应用程序后，我发现只要应用程序没有在本地托管，代码就可以运行...非常奇怪......这是我得到的错误。
LinksController＃destroy中的NoMethodError
nil的未定义方法`name'：NilClass
提取的来源（第59行）：
# DELETE /links/1.json
def destroy
@link.destroy
respond_to do |format|
format.html { redirect_to links_url, notice: 'Link was successfully destroyed.' }
format.json { head :no_content }
Rails.root：/ Users / ipbyrne / FirstRailsApp / raddit
应用程序跟踪|框架跟踪|完整追踪 app / controllers / links_controller.rb：59：在`destroy'中 请求
参数：
{"_method"=>"delete",
"authenticity_token"=>"3JyyNGNPHhdVcQ7tZQ64t+ouQjiNFnwxQXw25fgJGX4=",
"id"=>"5"}
我正在使用act_as_votable ruby gem。
下面的第一个块是我的show.html.erb，其中从
调用destroy方法第二个块是我的links_controller.rb文件。
<div class="page-header">
<h1><a href="<%= @link.url %>"><%= @link.title %></a><br> <small>Submitted by <%= @link.user.name %></small></h1>
</div>
<div class="btn-group">
<%= link_to 'Visit URL', @link.url, class: "btn btn-primary" %>
</div>
<div class="btn-group pull-right">
<%= link_to like_link_path(@link), method: :put, class: "btn btn-default btn-sm" do %>
<span class="glyphicon glyphicon-chevron-up"></span>
Upvote
<%= @link.get_upvotes.size %>
<% end %>
<%= link_to dislike_link_path(@link), method: :put, class: "btn btn-default btn-sm" do %>
<span class="glyphicon glyphicon-chevron-down">
Downvote
<%= @link.get_downvotes.size %>
<% end %>
</div>
<% if @link.user == current_user -%>
<div class="btn-group">
<%= link_to 'Edit', edit_link_path(@link), class: "btn btn-default" %>
<%= link_to 'Destroy', @link, method: :delete, data: { confirm: 'Are you sure?' }, class: "btn btn-default" %>
</div>
<% end %>
<h3 class="comments_title">
<%= @link.comments.count %> Comments
</h3>
<div id="comments">
<%= render :partial => @link.comments %>
</div>
<%= simple_form_for [@link, Comment.new] do |f| %>
<div class="field">
<%= f.text_area :body, class: "form-control" %>
</div>
<br>
<%= f.submit "Add Comment", class: "btn btn-primary" %>
<% end %>class LinksController < ApplicationController
before_action :set_link, only: [:show, :edit, :update, :destroy]
before_action :authenticate_user!, except: [:index, :show]
before_action :authorized_user, only: [:edit, :update, :destroy]
# GET /links
# GET /links.json
def index
@links = Link.all
end
# GET /links/1
# GET /links/1.json
def show
end
# GET /links/new
def new
@link = current_user.links.build
end
# GET /links/1/edit
def edit
end
# POST /links
# POST /links.json
def create
@link = current_user.links.build(link_params)
respond_to do |format|
if @link.save
format.html { redirect_to @link, notice: 'Link was successfully created.' }
format.json { render :show, status: :created, location: @link }
else
format.html { render :new }
format.json { render json: @link.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /links/1
# PATCH/PUT /links/1.json
def update
respond_to do |format|
if @link.update(link_params)
format.html { redirect_to @link, notice: 'Link was successfully updated.' }
format.json { render :show, status: :ok, location: @link }
else
format.html { render :edit }
format.json { render json: @link.errors, status: :unprocessable_entity }
end
end
end
# DELETE /links/1
# DELETE /links/1.json
def destroy
@link.destroy
respond_to do |format|
format.html { redirect_to links_url, notice: 'Link was successfully destroyed.' }
format.json { head :no_content }
end
end
def upvote
@link = Link.find(params[:id])
@link.upvote_by current_user
redirect_to :back
end
def downvote
@link = Link.find(params[:id])
@link.downvote_from current_user
redirect_to :back
end
private
# Use callbacks to share common setup or constraints between actions.
def set_link
@link = Link.find(params[:id])
end
def authorized_user
@link = current_user.links.find_by(id: params[:id])
redirect_to links_path, notice: "Not authorized to edit this link" if @link.nil?
end
# Never trust parameters from the scary internet, only allow the white list through.
def link_params
params.require(:link).permit(:title, :url)
end
end
完整跟踪错误
activerecord (4.0.0) lib/active_record/associations/has_many_association.rb:80:in `cached_counter_attribute_name'
activerecord (4.0.0) lib/active_record/associations/has_many_association.rb:103:in `inverse_updates_counter_cache?'
activerecord (4.0.0) lib/active_record/associations/has_many_association.rb:113:in `delete_records'
activerecord (4.0.0) lib/active_record/associations/collection_association.rb:493:in `remove_records'
activerecord (4.0.0) lib/active_record/associations/collection_association.rb:486:in `block in delete_or_destroy'
activerecord (4.0.0) lib/active_record/associations/collection_association.rb:152:in `block in transaction'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/database_statements.rb:200:in `transaction'
activerecord (4.0.0) lib/active_record/transactions.rb:209:in `transaction'
activerecord (4.0.0) lib/active_record/associations/collection_association.rb:151:in `transaction'
activerecord (4.0.0) lib/active_record/associations/collection_association.rb:486:in `delete_or_destroy'
activerecord (4.0.0) lib/active_record/associations/collection_association.rb:247:in `destroy'
activerecord (4.0.0) lib/active_record/associations/collection_association.rb:170:in `destroy_all'
activerecord (4.0.0) lib/active_record/associations/has_many_association.rb:26:in `handle_dependency'
activerecord (4.0.0) lib/active_record/associations/builder/association.rb:97:in `has_many_dependent_for_votes_for'
activesupport (4.0.0) lib/active_support/callbacks.rb:377:in `_run__4103742494544083763__destroy__callbacks'
activesupport (4.0.0) lib/active_support/callbacks.rb:80:in `run_callbacks'
activerecord (4.0.0) lib/active_record/callbacks.rb:289:in `destroy'
activerecord (4.0.0) lib/active_record/transactions.rb:265:in `block in destroy'
activerecord (4.0.0) lib/active_record/transactions.rb:326:in `block in with_transaction_returning_status'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/database_statements.rb:202:in `block in transaction'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/database_statements.rb:210:in `within_new_transaction'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/database_statements.rb:202:in `transaction'
activerecord (4.0.0) lib/active_record/transactions.rb:209:in `transaction'
activerecord (4.0.0) lib/active_record/transactions.rb:323:in `with_transaction_returning_status'
activerecord (4.0.0) lib/active_record/transactions.rb:265:in `destroy'
app/controllers/links_controller.rb:59:in `destroy'
actionpack (4.0.0) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (4.0.0) lib/abstract_controller/base.rb:189:in `process_action'
actionpack (4.0.0) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.0.0) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (4.0.0) lib/active_support/callbacks.rb:443:in `_run__1823692881447443679__process_action__callbacks'
activesupport (4.0.0) lib/active_support/callbacks.rb:80:in `run_callbacks'
actionpack (4.0.0) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (4.0.0) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.0.0) lib/action_controller/metal/instrumentation.rb:31:in `block in process_action'
activesupport (4.0.0) lib/active_support/notifications.rb:159:in `block in instrument'
activesupport (4.0.0) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.0.0) lib/active_support/notifications.rb:159:in `instrument'
actionpack (4.0.0) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.0.0) lib/action_controller/metal/params_wrapper.rb:245:in `process_action'
activerecord (4.0.0) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.0.0) lib/abstract_controller/base.rb:136:in `process'
actionpack (4.0.0) lib/abstract_controller/rendering.rb:44:in `process'
actionpack (4.0.0) lib/action_controller/metal.rb:195:in `dispatch'
actionpack (4.0.0) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.0.0) lib/action_controller/metal.rb:231:in `block in action'
actionpack (4.0.0) lib/action_dispatch/routing/route_set.rb:80:in `call'
actionpack (4.0.0) lib/action_dispatch/routing/route_set.rb:80:in `dispatch'
actionpack (4.0.0) lib/action_dispatch/routing/route_set.rb:48:in `call'
actionpack (4.0.0) lib/action_dispatch/journey/router.rb:71:in `block in call'
actionpack (4.0.0) lib/action_dispatch/journey/router.rb:59:in `each'
actionpack (4.0.0) lib/action_dispatch/journey/router.rb:59:in `call'
actionpack (4.0.0) lib/action_dispatch/routing/route_set.rb:655:in `call'
warden (1.2.3) lib/warden/manager.rb:35:in `block in call'
warden (1.2.3) lib/warden/manager.rb:34:in `catch'
warden (1.2.3) lib/warden/manager.rb:34:in `call'
rack (1.5.5) lib/rack/etag.rb:23:in `call'
rack (1.5.5) lib/rack/conditionalget.rb:35:in `call'
rack (1.5.5) lib/rack/head.rb:11:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/flash.rb:241:in `call'
rack (1.5.5) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.5.5) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/cookies.rb:486:in `call'
activerecord (4.0.0) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:626:in `call'
activerecord (4.0.0) lib/active_record/migration.rb:369:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.0.0) lib/active_support/callbacks.rb:373:in `_run__1414070385979111640__call__callbacks'
activesupport (4.0.0) lib/active_support/callbacks.rb:80:in `run_callbacks'
actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/reloader.rb:64:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.0.0) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.0.0) lib/rails/rack/logger.rb:21:in `block in call'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `block in tagged'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:25:in `tagged'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `tagged'
railties (4.0.0) lib/rails/rack/logger.rb:21:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.5.5) lib/rack/methodoverride.rb:21:in `call'
rack (1.5.5) lib/rack/runtime.rb:17:in `call'
activesupport (4.0.0) lib/active_support/cache/strategy/local_cache.rb:83:in `call'
rack (1.5.5) lib/rack/lock.rb:17:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/static.rb:64:in `call'
railties (4.0.0) lib/rails/engine.rb:511:in `call'
railties (4.0.0) lib/rails/application.rb:97:in `call'
rack (1.5.5) lib/rack/lock.rb:17:in `call'
rack (1.5.5) lib/rack/content_length.rb:14:in `call'
rack (1.5.5) lib/rack/handler/webrick.rb:60:in `service'
/Users/ipbyrne/.rvm/rubies/ruby-2.2.1/lib/ruby/2.2.0/webrick/httpserver.rb:138:in `service'
/Users/ipbyrne/.rvm/rubies/ruby-2.2.1/lib/ruby/2.2.0/webrick/httpserver.rb:94:in `run'
/Users/ipbyrne/.rvm/rubies/ruby-2.2.1/lib/ruby/2.2.0/webrick/server.rb:294:in `block in start_thread'
Link.rb
class Link < ActiveRecord::Base
acts_as_votable
belongs_to :user
has_many :comments
end
模式
# encoding: UTF-8
# This file is auto-generated from the current state of the database. Instead
# of editing this file, please use the migrations feature of Active Record to
# incrementally modify your database, and then regenerate this schema definition.
#
# Note that this schema.rb definition is the authoritative source for your
# database schema. If you need to create the application database on another
# system, you should be using db:schema:load, not running all the migrations
# from scratch. The latter is a flawed and unsustainable approach (the more migrations
# you'll amass, the slower it'll run and the greater likelihood for issues).
#
# It's strongly recommended that you check this file into your version control system.
ActiveRecord::Schema.define(version: 20150722133429) do
create_table "comments", force: true do |t|
t.integer "link_id"
t.text "body"
t.integer "user_id"
t.datetime "created_at"
t.datetime "updated_at"
end
add_index "comments", ["link_id"], name: "index_comments_on_link_id"
add_index "comments", ["user_id"], name: "index_comments_on_user_id"
create_table "links", force: true do |t|
t.string "title"
t.string "url"
t.datetime "created_at"
t.datetime "updated_at"
t.integer "user_id"
end
add_index "links", ["user_id"], name: "index_links_on_user_id"
create_table "users", force: true do |t|
t.string "email", default: "", null: false
t.string "encrypted_password", default: "", null: false
t.string "reset_password_token"
t.datetime "reset_password_sent_at"
t.datetime "remember_created_at"
t.integer "sign_in_count", default: 0, null: false
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string "current_sign_in_ip"
t.string "last_sign_in_ip"
t.datetime "created_at"
t.datetime "updated_at"
t.string "name"
end
add_index "users", ["email"], name: "index_users_on_email", unique: true
add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
create_table "votes", force: true do |t|
t.integer "votable_id"
t.string "votable_type"
t.integer "voter_id"
t.string "voter_type"
t.boolean "vote_flag"
t.string "vote_scope"
t.integer "vote_weight"
t.datetime "created_at"
t.datetime "updated_at"
end
add_index "votes", ["votable_id", "votable_type", "vote_scope"], name: "index_votes_on_votable_id_and_votable_type_and_vote_scope"
add_index "votes", ["voter_id", "voter_type", "vote_scope"], name: "index_votes_on_voter_id_and_voter_type_and_vote_scope"
end
链接模型
class Link < ActiveRecord::Base
acts_as_votable
belongs_to :user
has_many :comments
end
答案 0 :(得分：0)
错误必须位于index.html.erb文件中。你在一些零对象上调用'name'。
答案 1 :(得分：0)
听起来你无法删除它，因为该链接已经关联了投票。您必须更新Link模型中的关系，以便它允许allow_destroy: true，在这种情况下，它也会删除关联。