ruby-on-rails - Ruby on Rails： url_for :back 导致 back_url 的 NoMethodError

Question

我正在尝试使用 url_for(:back) 在用户登录时创建一个重定向到上一页的重定向。

当用户自己进入登录页面时，我已经成功地工作了。但是，当用户由于访问需要对用户进行身份验证的页面而被重定向到登录页面时，重定向会将用户返回到他/她尝试访问权限不足的页面之前的页面。

我正在尝试修改我的登录控制器操作以正确处理重定向。我的计划是在发生强制重定向时使用查询字符串参数“redirect”。在控制器中，如果该参数存在，则使用该 URL；否则，使用 url_for(:back)，或者如果这不起作用（由于缺少 HTTP_REFERER），那么用户将被重定向到站点的主页。

这是应该实现此逻辑的代码片段：

if params[:redirect]
  @url = params[:redirect]
else
  @url = url_for :back
  @url ||= url_for :controller => "home", :action => "index"
end

我得到的错误是：

用户控制器中的 NoMethodError#login

未定义的方法 `back_url' 用于#

RAILS_ROOT：[模糊]
应用程序跟踪 | 框架跟踪 | 全跟踪

供应商/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `__send__'
供应商/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `polymorphic_url'
供应商/rails/actionpack/lib/action_controller/base.rb:628:in `url_for'
app/controllers/users_controller.rb:16:in `login'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `进程'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `同步'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:在“进程”中
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `每个'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:在“运行”中
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `初始化'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:在“运行”中
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:在“运行”中
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:在“运行”中
/var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run'
/var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281

供应商/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `__send__'
供应商/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `polymorphic_url'
供应商/rails/actionpack/lib/action_controller/base.rb:628:in `url_for'
供应商/rails/actionpack/lib/action_controller/base.rb:1256:in `send'
供应商/rails/actionpack/lib/action_controller/base.rb:1256:in `perform_action_without_filters'
供应商/rails/actionpack/lib/action_controller/filters.rb:617:in `call_filters'
供应商/rails/actionpack/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark'
供应商/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/usr/lib/ruby/1.8/benchmark.rb:293:in `measure'
供应商/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
供应商/rails/actionpack/lib/action_controller/rescue.rb:136:in `perform_action_without_caching'
供应商/rails/actionpack/lib/action_controller/caching/sql_cache.rb:13:in `perform_action'
供应商/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache'
供应商/rails/activerecord/lib/active_record/query_cache.rb:8:in `cache'
供应商/rails/actionpack/lib/action_controller/caching/sql_cache.rb:12:in `perform_action'
供应商/rails/actionpack/lib/action_controller/base.rb:524:in `send'
供应商/rails/actionpack/lib/action_controller/base.rb:524:in `process_without_filters'
供应商/rails/actionpack/lib/action_controller/filters.rb:606:in `process_without_session_management_support'
供应商/rails/actionpack/lib/action_controller/session_management.rb:134:in `process'
供应商/rails/actionpack/lib/action_controller/base.rb:392：在“进程”中
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:184:in `handle_request'
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:112:in `dispatch_unlocked'
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:125:in `dispatch'
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:124：在“同步”中
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `dispatch'
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:134:in `dispatch_cgi'
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:41:in `dispatch'
供应商/rails/activesupport/lib/active_support/dependencies.rb:142:in `load_without_new_constant_marking'
供应商/rails/activesupport/lib/active_support/dependencies.rb:142:in `load'
供应商/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in'
供应商/rails/activesupport/lib/active_support/dependencies.rb:142:in `load'
供应商/rails/railties/lib/commands/servers/mongrel.rb:64
/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
供应商/rails/activesupport/lib/active_support/dependencies.rb:153:in `require'
供应商/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in'
供应商/rails/activesupport/lib/active_support/dependencies.rb:153:in `require'
供应商/rails/railties/lib/commands/server.rb:49
/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
脚本/服务器：3

供应商/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `__send__'
供应商/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `polymorphic_url'
供应商/rails/actionpack/lib/action_controller/base.rb:628:in `url_for'
app/controllers/users_controller.rb:16:in `login'
供应商/rails/actionpack/lib/action_controller/base.rb:1256:in `send'
供应商/rails/actionpack/lib/action_controller/base.rb:1256:in `perform_action_without_filters'
供应商/rails/actionpack/lib/action_controller/filters.rb:617:in `call_filters'
供应商/rails/actionpack/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark'
供应商/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/usr/lib/ruby/1.8/benchmark.rb:293:in `measure'
供应商/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
供应商/rails/actionpack/lib/action_controller/rescue.rb:136:in `perform_action_without_caching'
供应商/rails/actionpack/lib/action_controller/caching/sql_cache.rb:13:in `perform_action'
供应商/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache'
供应商/rails/activerecord/lib/active_record/query_cache.rb:8:in `cache'
供应商/rails/actionpack/lib/action_controller/caching/sql_cache.rb:12:in `perform_action'
供应商/rails/actionpack/lib/action_controller/base.rb:524:in `send'
供应商/rails/actionpack/lib/action_controller/base.rb:524:in `process_without_filters'
供应商/rails/actionpack/lib/action_controller/filters.rb:606:in `process_without_session_management_support'
供应商/rails/actionpack/lib/action_controller/session_management.rb:134:in `process'
供应商/rails/actionpack/lib/action_controller/base.rb:392：在“进程”中
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:184:in `handle_request'
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:112:in `dispatch_unlocked'
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:125:in `dispatch'
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:124：在“同步”中
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `dispatch'
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:134:in `dispatch_cgi'
供应商/rails/actionpack/lib/action_controller/dispatcher.rb:41:in `dispatch'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `进程'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `同步'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:在“进程”中
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `每个'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:在“运行”中
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `初始化'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:在“运行”中
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:在“运行”中
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:在“运行”中
/var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run'
/var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run'
/var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281
供应商/rails/activesupport/lib/active_support/dependencies.rb:142:in `load_without_new_constant_marking'
供应商/rails/activesupport/lib/active_support/dependencies.rb:142:in `load'
供应商/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in'
供应商/rails/activesupport/lib/active_support/dependencies.rb:142:in `load'
供应商/rails/railties/lib/commands/servers/mongrel.rb:64
/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
供应商/rails/activesupport/lib/active_support/dependencies.rb:153:in `require'
供应商/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in'
供应商/rails/activesupport/lib/active_support/dependencies.rb:153:in `require'
供应商/rails/railties/lib/commands/server.rb:49
/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
脚本/服务器：3

要求

参数：

没有任何

显示会话转储

---
：用户：
:csrf_id: 2927cca61bbbe97218362b5bcdb74c0f
flash: !map:ActionController::Flash::FlashHash {}


回复

标题：

{"内容类型"=>"",
 “饼干”=>[],
 “缓存控制”=>“无缓存”}

请记住，我之前已经让它工作了—— url_for(:back) 在我添加这个逻辑之前就知道如何正确操作。

提前感谢您的任何想法！

Answer 1

您正在尝试在控制器中使用视图辅助方法。您期望的行为位于 ActionView::Helpers::UrlHelper 中，但您调用的方法位于 ActionController::Base 中。不幸的是，这两种方法的名称相同，功能也非常相似，但并不完全相同。

为了快速修复，ActionController::Base 设置了一个@template可以访问所有 ActionView 助手的变量。尝试url_for从该对象调用，如下所示：

if params[:redirect]
  @url = params[:redirect]
else
  @url = @template.url_for :back
  @url ||= url_for :controller => "home", :action => "index"
end

但是，我不确定这是“正确”的做法。如果 Rails 开发人员希望我们@template不顾一切地使用该变量，他们会更多地宣传它。

另一种获取原始引荐来源网址（您正在寻找的 :back ）的方法是使用以下request方法：

if params[:redirect]
  @url = params[:redirect]
else
  @url = request.env["HTTP_REFERER"]
  @url ||= url_for :controller => "home", :action => "index"
end

Answer 2

就我而言，有时 :back 指向我想离开的同一个地方，因此会发生循环。我的解决方案是：application_controller 中的方法

def new_loc
  url = request.referer.to_s
  url == "" || url == request.url ? root_path : url
end

在你的控制器中

@url = params[:redirect] ? params[:redirect] : new_loc

或者在我的情况下

redirect_to new_loc

而已。我在 Rails 5 上