UsersController 中没有方法错误
几周前我开始在 Rails 中编码，但我不明白为什么会出现这个错误。我使用 Devise 进行登录，使用 Formtastic 进行表单。在我添加 Acts_like_tags_on 并重置数据库之前，该应用程序一直正常工作。
错误信息： UsersController#show 中的 NoMethodError
undefined method `username' for nil:NilClass
app/controllers/users_controller.rb:19:in `show'
Request
Parameters:
{"id"=>"sign_in"}
这是我在用户控制器中的内容：
def show
@user = User.find_by_username(params[:id])
@title = @user.username
respond_to do |format|
format.html # show.html.erb
format.json { render json: @user }
end
end
任何输入都会有帮助。谢谢！
将 @user = User.find_by_username(params[:id]) 编辑为： @user = User.find_by_user(params[:id])
错误变为： undefined method `find_by_user' for #
用户名列确实存在于用户表中。
I began coding in Rails several weeks ago, and I can't figure out why I have this error. I'm using Devise for log-ins and Formtastic for forms. The app was working correctly until I added the Acts_like_tags_on and reset the database.
The error message:
NoMethodError in UsersController#show
undefined method `username' for nil:NilClass
app/controllers/users_controller.rb:19:in `show'
Request
Parameters:
{"id"=>"sign_in"}
This is what I have in the Users Controller:
def show
@user = User.find_by_username(params[:id])
@title = @user.username
respond_to do |format|
format.html # show.html.erb
format.json { render json: @user }
end
end
Any input would be helpful. Thanks!
After editing @user = User.find_by_username(params[:id]) to:
@user = User.find_by_user(params[:id])
The error becomes:
undefined method `find_by_user' for #
The username column does exist in the User table.
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上面那行可能返回零。如果你执行 User.find_by_username("Superman-is-awesome") 并且该用户名不存在于你的数据库中，它将返回 nil。
然后它试图做：
这本质上是：
这当然行不通。因此，您传入的参数可能有问题。
另外，请确保您的用户表有一列名为“用户名”的列？确保你已经运行：
以及。
That line above may be returning nil. If you do User.find_by_username("Superman-is-awesome") and that username does not exist in your database, it's going to return nil.
Then it is trying to do:
Which is essentially:
Which of course won't work. So could be something wrong with the parameter you are passing in.
Also, make sure your User table have a column called 'username'? Make sure you've run:
As well.
如果正确配置了路由，则应该在用户资源之前设计路由，如下所示：
If you configured the routes correctly, you should have devise routes BEFORE user resource, like this:
这实际上是一个路由问题
问题是 devise 期望您有一个路由将：
“/users/sign_in”转换为sessions#new，
但您的路由文件缺少该路由，因此调度程序与：
“ users/:id” 路由然后转到：
users#show with :id =>; 'sign_in'
（因此当它尝试查找 id 为“sign_in”的用户时会抛出错误）
您需要阅读 devise 的 README 文档（如果您本地没有，请谷歌） - 尤其是描述的部分如何将标准路由集添加到 config/routes.rb 然后执行它所说的操作。 :)
应该在那之后。
This is actually a routing problem
The problem is that devise expects you to have a route that will turn:
"/users/sign_in" into sessions#new
but your routes file is missing that route, and so the dispatcher is matching against the:
"users/:id" route which then goes to:
users#show with :id => 'sign_in'
(and hence throws an error when it tries to find a user with the id of "sign_in")
You need to read the README doc for devise (google if you don't have it locally) - especially the part that describes how to add the standard set of routes to config/routes.rb Then do whatever it says. :)
Should be right after that.
我发现 user_id 被赋予了“users”值。在我的routes.rb中注释掉以下行后，id不再被赋予该值。
我还需要 users_controllers #show 具有以下行，因为我的用户路径使用用户名。删除“_by_username”会导致调用用户名的页面出现错误：
I found that the user_id was being given the value of 'users'. After commenting the following line out in my routes.rb, the id was no longer given that value.
I also needed the users_controllers #show to have the following line, since my user path uses the username. removing '_by_username' caused an error on pages that called for the username: