问题将参数从erb模板传递到Rails中的控制器

【问题标题】：Issue Passing parameters from erb template to controller in Rails问题将参数从erb模板传递到Rails中的控制器
【发布时间】：2019-12-24 04:21:39
【问题描述】：

我正在尝试从其各自的控制器调用视图模板中的一个方法，该控制器根据不同的条件表现得很奇怪。

请注意，我在此操作失败后尝试过此操作 Triply nested model's form in rails showing error

首先将控制器方法定义为->

  helper_method :find_feature

  def find_feature(fid)
    @project.features.find(fid)
  end

以及调用该方法的视图文件代码->

<% @project.features.each do |fet| %>
  <%= "#{fet.name} #{fet.id} " %>  #It does work!!

  <%= render partial: "taskform",locals: { fetr: find_feature(fet.id) } %>
<% end %>

这会引发错误为Couldn't find Feature without an ID

在屏幕截图中显示了 params[:id] 是不对的 抱歉，我使用了上面写的方法 find_feature(fid) 非常抱歉，一旦我得到，我将更新屏幕截图到我的mqchine

**

错误显示在 find_feature(fet.id) 调用时无法找到没有 id 的功能

**

但是当我手动使用 id 显式测试时，例如->

&lt;%= render partial: "taskform", locals: { fetr: find_feature(7) } %&gt;

这行得通！

完整的堆栈跟踪-

activerecord (5.2.3) lib/active_record/relation/finder_methods.rb:433:in `find_with_ids'
activerecord (5.2.3) lib/active_record/relation/finder_methods.rb:69:in `find'
activerecord (5.2.3) lib/active_record/associations/collection_association.rb:100:in `find'
activerecord (5.2.3) lib/active_record/associations/collection_proxy.rb:140:in `find'
app/controllers/projects_controller.rb:7:in `find_feature'
actionpack (5.2.3) lib/abstract_controller/helpers.rb:67:in `find_feature'
app/views/projects/show.html.erb:66:in `block in _app_views_projects_show_html_erb__3383934460746758134_70317115637280'
activerecord (5.2.3) lib/active_record/relation/delegation.rb:71:in `each'
activerecord (5.2.3) lib/active_record/relation/delegation.rb:71:in `each'
app/views/projects/show.html.erb:56:in `_app_views_projects_show_html_erb__3383934460746758134_70317115637280'
actionview (5.2.3) lib/action_view/template.rb:159:in `block in render'
activesupport (5.2.3) lib/active_support/notifications.rb:170:in `instrument'
actionview (5.2.3) lib/action_view/template.rb:354:in `instrument_render_template'
actionview (5.2.3) lib/action_view/template.rb:157:in `render'
actionview (5.2.3) lib/action_view/renderer/template_renderer.rb:54:in `block (2 levels) in render_template'
actionview (5.2.3) lib/action_view/renderer/abstract_renderer.rb:44:in `block in instrument'
activesupport (5.2.3) lib/active_support/notifications.rb:168:in `block in instrument'
activesupport (5.2.3) lib/active_support/notifications/instrumenter.rb:23:in `instrument'
activesupport (5.2.3) lib/active_support/notifications.rb:168:in `instrument'
actionview (5.2.3) lib/action_view/renderer/abstract_renderer.rb:43:in `instrument'
actionview (5.2.3) lib/action_view/renderer/template_renderer.rb:53:in `block in render_template'
actionview (5.2.3) lib/action_view/renderer/template_renderer.rb:61:in `render_with_layout'
actionview (5.2.3) lib/action_view/renderer/template_renderer.rb:52:in `render_template'
actionview (5.2.3) lib/action_view/renderer/template_renderer.rb:16:in `render'
actionview (5.2.3) lib/action_view/renderer/renderer.rb:44:in `render_template'
actionview (5.2.3) lib/action_view/renderer/renderer.rb:25:in `render'
actionview (5.2.3) lib/action_view/rendering.rb:103:in `_render_template'
actionpack (5.2.3) lib/action_controller/metal/streaming.rb:219:in `_render_template'
actionview (5.2.3) lib/action_view/rendering.rb:84:in `render_to_body'
actionpack (5.2.3) lib/action_controller/metal/rendering.rb:52:in `render_to_body'
actionpack (5.2.3) lib/action_controller/metal/renderers.rb:142:in `render_to_body'
actionpack (5.2.3) lib/abstract_controller/rendering.rb:25:in `render'
actionpack (5.2.3) lib/action_controller/metal/rendering.rb:36:in `render'
actionpack (5.2.3) lib/action_controller/metal/instrumentation.rb:46:in `block (2 levels) in render'
activesupport (5.2.3) lib/active_support/core_ext/benchmark.rb:14:in `block in ms'
/home/ayan/.rvm/rubies/ruby-2.6.3/lib/ruby/2.6.0/benchmark.rb:308:in `realtime'
activesupport (5.2.3) lib/active_support/core_ext/benchmark.rb:14:in `ms'
actionpack (5.2.3) lib/action_controller/metal/instrumentation.rb:46:in `block in render'
actionpack (5.2.3) lib/action_controller/metal/instrumentation.rb:87:in `cleanup_view_runtime'
activerecord (5.2.3) lib/active_record/railties/controller_runtime.rb:31:in `cleanup_view_runtime'
actionpack (5.2.3) lib/action_controller/metal/instrumentation.rb:45:in `render'
actionpack (5.2.3) lib/action_controller/metal/implicit_render.rb:35:in `default_render'
actionpack (5.2.3) lib/action_controller/metal/basic_implicit_render.rb:6:in `block in send_action'
actionpack (5.2.3) lib/action_controller/metal/basic_implicit_render.rb:6:in `tap'
actionpack (5.2.3) lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
actionpack (5.2.3) lib/abstract_controller/base.rb:194:in `process_action'
actionpack (5.2.3) lib/action_controller/metal/rendering.rb:30:in `process_action'
actionpack (5.2.3) lib/abstract_controller/callbacks.rb:42:in `block in process_action'
activesupport (5.2.3) lib/active_support/callbacks.rb:132:in `run_callbacks'
actionpack (5.2.3) lib/abstract_controller/callbacks.rb:41:in `process_action'
actionpack (5.2.3) lib/action_controller/metal/rescue.rb:22:in `process_action'
actionpack (5.2.3) lib/action_controller/metal/instrumentation.rb:34:in `block in process_action'
activesupport (5.2.3) lib/active_support/notifications.rb:168:in `block in instrument'
activesupport (5.2.3) lib/active_support/notifications/instrumenter.rb:23:in `instrument'
activesupport (5.2.3) lib/active_support/notifications.rb:168:in `instrument'
actionpack (5.2.3) lib/action_controller/metal/instrumentation.rb:32:in `process_action'
actionpack (5.2.3) lib/action_controller/metal/params_wrapper.rb:256:in `process_action'
activerecord (5.2.3) lib/active_record/railties/controller_runtime.rb:24:in `process_action'
actionpack (5.2.3) lib/abstract_controller/base.rb:134:in `process'
actionview (5.2.3) lib/action_view/rendering.rb:32:in `process'
actionpack (5.2.3) lib/action_controller/metal.rb:191:in `dispatch'
actionpack (5.2.3) lib/action_controller/metal.rb:252:in `dispatch'
actionpack (5.2.3) lib/action_dispatch/routing/route_set.rb:52:in `dispatch'
actionpack (5.2.3) lib/action_dispatch/routing/route_set.rb:34:in `serve'
actionpack (5.2.3) lib/action_dispatch/journey/router.rb:52:in `block in serve'
actionpack (5.2.3) lib/action_dispatch/journey/router.rb:35:in `each'
actionpack (5.2.3) lib/action_dispatch/journey/router.rb:35:in `serve'
actionpack (5.2.3) lib/action_dispatch/routing/route_set.rb:840:in `call'
omniauth (1.9.0) lib/omniauth/strategy.rb:192:in `call!'
omniauth (1.9.0) lib/omniauth/strategy.rb:169:in `call'
omniauth (1.9.0) lib/omniauth/builder.rb:64:in `call'
rack (2.0.7) lib/rack/tempfile_reaper.rb:15:in `call'
rack (2.0.7) lib/rack/etag.rb:25:in `call'
rack (2.0.7) lib/rack/conditional_get.rb:25:in `call'
rack (2.0.7) lib/rack/head.rb:12:in `call'
actionpack (5.2.3) lib/action_dispatch/http/content_security_policy.rb:18:in `call'
rack (2.0.7) lib/rack/session/abstract/id.rb:232:in `context'
rack (2.0.7) lib/rack/session/abstract/id.rb:226:in `call'
actionpack (5.2.3) lib/action_dispatch/middleware/cookies.rb:670:in `call'
activerecord (5.2.3) lib/active_record/migration.rb:559:in `call'
actionpack (5.2.3) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
activesupport (5.2.3) lib/active_support/callbacks.rb:98:in `run_callbacks'
actionpack (5.2.3) lib/action_dispatch/middleware/callbacks.rb:26:in `call'
actionpack (5.2.3) lib/action_dispatch/middleware/executor.rb:14:in `call'
actionpack (5.2.3) lib/action_dispatch/middleware/debug_exceptions.rb:61:in `call'
web-console (3.7.0) lib/web_console/middleware.rb:135:in `call_app'
web-console (3.7.0) lib/web_console/middleware.rb:30:in `block in call'
web-console (3.7.0) lib/web_console/middleware.rb:20:in `catch'
web-console (3.7.0) lib/web_console/middleware.rb:20:in `call'
actionpack (5.2.3) lib/action_dispatch/middleware/show_exceptions.rb:33:in `call'
railties (5.2.3) lib/rails/rack/logger.rb:38:in `call_app'
railties (5.2.3) lib/rails/rack/logger.rb:26:in `block in call'
activesupport (5.2.3) lib/active_support/tagged_logging.rb:71:in `block in tagged'
activesupport (5.2.3) lib/active_support/tagged_logging.rb:28:in `tagged'
activesupport (5.2.3) lib/active_support/tagged_logging.rb:71:in `tagged'
railties (5.2.3) lib/rails/rack/logger.rb:26:in `call'
sprockets-rails (3.2.1) lib/sprockets/rails/quiet_assets.rb:13:in `call'
actionpack (5.2.3) lib/action_dispatch/middleware/remote_ip.rb:81:in `call'
actionpack (5.2.3) lib/action_dispatch/middleware/request_id.rb:27:in `call'
rack (2.0.7) lib/rack/method_override.rb:22:in `call'
rack (2.0.7) lib/rack/runtime.rb:22:in `call'
activesupport (5.2.3) lib/active_support/cache/strategy/local_cache_middleware.rb:29:in `call'
actionpack (5.2.3) lib/action_dispatch/middleware/executor.rb:14:in `call'
actionpack (5.2.3) lib/action_dispatch/middleware/static.rb:127:in `call'
rack (2.0.7) lib/rack/sendfile.rb:111:in `call'
railties (5.2.3) lib/rails/engine.rb:524:in `call'
puma (3.12.1) lib/puma/configuration.rb:227:in `call'
puma (3.12.1) lib/puma/server.rb:660:in `handle_request'
puma (3.12.1) lib/puma/server.rb:474:in `process_client'
puma (3.12.1) lib/puma/server.rb:334:in `block in run'
puma (3.12.1) lib/puma/thread_pool.rb:135:in `block in spawn_thread'
Request
Parameters:

{"id"=>"4"}

谁能指出这种行为的原因是什么？

【问题讨论】：

  • 执行find_feature(fet.id) 时收到的参数是什么？请问，find_feature 应该怎么做，如果你在数据库中寻找你获取 id 的同一个对象？
  • 请参考我为您的问题附加的屏幕截图 -您在执行 find_feature(fet.id) 时收到的参数是什么 似乎在当find_feature(7)成功发送参数时，这一切都令人惊讶
  • 那里没有参数。
  • 参数永远不会为空，除非你明确地编辑它们。从一些日志中添加完整的堆栈跟踪，没有照片。
  • 请问，find_feature 应该做什么 - 它只是通过其 ID 查找来返回一个功能，值得注意的是我不是从 FeaturesController 执行此操作，存在嵌套我从它的父控制器调用它

标签： ruby-on-rails model-view-controller methods ruby-on-rails-5 parameter-passing


【解决方案1】：

错误显示使用 parmas[:fid] 调用的方法，但是您将方法定义为 find_feature(fid) 以查找特征，因此必须有其他方法可以覆盖，请尝试使用不同的名称，例如 find_project_features 它会起作用

【讨论】：

  • 如果这是问题所在，那么为什么当我明确给出一个 id 作为参数时它会起作用 &lt;%= render partial: "taskform", locals: { fetr: find_feature(7) } %&gt; @Ashok
  • app/controllers/projects_controller.rb:7 这是从您的方法调用的地方，它与您定义为 helper_method 的方法相同吗？
  • 当你已经在循环中有 'fetr' 对象时还有一件事，你不直接传递，你为什么要找到它并触发额外的查询？
  • 如果你的要求很好，否则你应该编写短代码，如 ，这样你不需要循环对象
【解决方案2】：

您正在使用此代码 find_feature(fet.id) 调用 find_feature，因此您希望将 id 作为参数传递。

然后以这种方式定义 helper_method：

def find_feature(fid)
  @project.features.find(fid)
end

params[:fid] 将在请求的 params 哈希中查找键为 fid 的请求参数，当您调用该方法时，您正在将特定值传递给该方法。

编辑：无论如何，我不确定你为什么要这样做，你已经在循环内的 fet 变量上拥有特征对象，只需这样做：

<%= render partial: "taskform",locals: { fetr: fet } %>

【讨论】：

  • 我非常抱歉我发布了一些更新的代码，首先我尝试了，请查看编辑后的问题，实际上在一些 cmets 之后我改变了不同的东西，但没有任何效果
  • 当然，我一开始就试过了，但那不起作用
  • 其实它是一个三重嵌套的表单，它是第三级表单
  • 您没有在模型的定义 find_feature(fid) 上添加 (fid) 参数，但我认为您甚至不需要调用该方法。
  • but that is not working &lt;%= render partial: "taskform",locals: { fetr: fet } %&gt; 怎么会“不工作”？我敢打赌这是一个不同的错误，请更准确，“不工作”太模棱两可了。
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