Rails和Devise的Gravatar问题

Question

我正在尝试创建一个简单的个人资料标签，其中包含一个使用Devise的gravatar，但是我一直收到一封undefined method电子邮件给nil：NilClass`''看看我哪里出错了

tab_check.html.erb

<div class="tabbable"> <!-- Only required for left/right tabs -->
  <ul class="nav nav-tabs">
    <li class="active"><a href="#tab1" data-toggle="tab">Dashboard</a></li>
    <li><a href="#tab2" data-toggle="tab">Inbox</a></li>
    <li><a href="#tab3" data-toggle="tab">Three</a></li>
    <li><a href="#tab4" data-toggle="tab">Four</a></li>
    <li><a href="#tab5" data-toggle="tab">Profile</a></li>

    <li><a href="#tab6" data-toggle="tab">Account</a></li>
  </ul>
  <div class="tab-content">
    <div class="tab-pane active" id="tab1">
      <p>This will be the Dashboard</p>
    </div>
    <div class="tab-pane" id="tab2">
      <p>This will be the Inbox</p>
    </div>
    <div class="tab-pane" id="tab3">
      <p>This will be tab 3</p>
    </div>
    <div class="tab-pane" id="tab4">
      <p>This will be tab 4/p>
    </div>
    <div class="tab-pane" id="tab5">
      <%= render 'users/show' %>
    </div>
    <div class="tab-pane" id="tab6">
      <p>Account settings sections email etc</p>
    </div>
  </div>
</div>

users_controller.rb

class UsersController < ApplicationController

  def index
    @users = User.all
  end

  def show
    @user = User.find(params[:id])
  end
end

user.rb

class User < ActiveRecord::Base
  # Include default devise modules. Others available are:
  # :token_authenticatable, :confirmable,
  # :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable

  # Setup accessible (or protected) attributes for your model
  attr_accessible :email, :password, :password_confirmation, :remember_me,
                                :first_name, :last_name
  # attr_accessible :title, :body

  has_many :items
end

users_helper.rb

module UsersHelper
  def gravatar_for(user, options = { size: 50})
    gravatar_id = Digest::MD5::hexdigest(user.email.downcase)
    size = options[:size]
    gravatar_url = "http://gravatar.com/avatar/#{gravatar_id}.png?s=#{size}"
    image_tag(gravatar_url, alt: user.name, class: "gravatar")
  end
 end

最后是_show.heml.erb

<div class="row">
  <aside class="span4">
    <section>
      <h1>
        <%= gravatar_for @user %>
        <%= @user.first_name %>
      </h1>
    </section>
  </aside>
</div>

编辑：完整堆栈跟踪：

app/helpers/users_helper.rb:3:in `gravatar_for'
app/views/users/_show.html.erb:5:in `_app_views_users__show_html_erb__248270508__620770878'
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/tab_check.html.erb:25:in `_app_views_static_pages_tab_check_html_erb___410072822_92462190'
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'
/home/toaksie/.rvm/rubies/ruby-1.9.3-p194/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'
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:4: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:414:in `_run__447462369__process_action__180978766__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 (1.0.3) lib/journey/router.rb:68:in `block in call'
journey (1.0.3) lib/journey/router.rb:56:in `each'
journey (1.0.3) lib/journey/router.rb:56:in `call'
actionpack (3.2.3) lib/action_dispatch/routing/route_set.rb:600:in `call'
warden (1.1.1) lib/warden/manager.rb:35:in `block in call'
warden (1.1.1) lib/warden/manager.rb:34:in `catch'
warden (1.1.1) lib/warden/manager.rb:34:in `call'
actionpack (3.2.3) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.4.1) lib/rack/etag.rb:23:in `call'
rack (1.4.1) 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 (1.4.1) lib/rack/session/abstract/id.rb:205:in `context'
rack (1.4.1) lib/rack/session/abstract/id.rb:200: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__496782642__call__984513863__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 (1.4.1) lib/rack/methodoverride.rb:21:in `call'
rack (1.4.1) lib/rack/runtime.rb:17:in `call'
activesupport (3.2.3) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.4.1) 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 (1.4.1) lib/rack/content_length.rb:14:in `call'
railties (3.2.3) lib/rails/rack/log_tailer.rb:14:in `call'
rack (1.4.1) lib/rack/handler/webrick.rb:59:in `service'
/home/toaksie/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
/home/toaksie/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
/home/toaksie/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'

非常感谢任何指针。感谢

Answer 1

您的prbolem是您在tab_check.html.erb中呈现show模板，但未初始化用户。如果在show视图上使用部分渲染，则show动作未运行，用户也必须在tab_check动作中设置。

将@user = User.find(params[:id])添加到您的tab_check操作。