Rubyonrails 会话控制器中的某种问题

# add user model v
form_with(model: @user, url: sessions_path, method: :post)

这样，生成的输入name属性将是user[email]和user[password].因为您的params必须具有用户密钥:{user: {email: "myemail", password: "123"}}，因为您需要它params.require(:user).

此外，如果您有Turbo个错误响应(在rails 7中默认为Turbo个)，您将需要它才能显示错误响应:

render :new, status: :unprocessable_entity

Update个

创建表单时，最重要的部分是表单构建器生成的name个属性:

<%= form_with url: "/sign_in", method: :post do |f| %>
  <%= f.text_field :email %>
  <%#=> <input type="text" name="email"> %>
<% end %> #                      ^^^^^

<%= form_with model: @user, url: "/sign_in", method: :post do |f| %>
  <%= f.text_field :email %>
  <%#=> <input type="text" name="user[email]"> %>
<% end %> #                      ^^^^^^^^^^^

You just have to know how form_with works:
https://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-form_with

提交表单将把您带到SessionsController#create，提交的表单参数由Rails解析，并在params助手中可用，对于URL编码的参数，它看起来如下所示:

#                                   name=value
>> Rack::Utils.parse_nested_query("email=asdf")
=> {"email"=>"asdf"}
>> Rack::Utils.parse_nested_query("user[email]=asdf")
=> {"user"=>{"email"=>"asdf"}}

默认情况下，params返回ActionController::Parameters对象.你必须允许参数，这样你才能把它们提供给User型号.这是不允许的:User.create(params)，因为我可以发送email=myemail&superadmin=true，而现在我负责.

In your controller, first thing that happens is a call to
user_params[:email] => params.require(:user).permit(:email,:password)

>> parameters = Rack::Utils.parse_nested_query("email=myemail")
>> params     = ActionController::Parameters.new(parameters)
#  ^ this is what you have
#  v this is what happens (you have to look at server logs)
>> params.require(:user)
/home/alex/.rbenv/versions/3.2.2/lib/ruby/gems/3.2.0/gems/actionpack-7.0.4.3/lib/action_controller/metal/strong_parameters.rb:500:in `require':
param is missing or the value is empty: user (ActionController::ParameterMissing)

如果加上model: @user:

>> parameters = Rack::Utils.parse_nested_query("user%5Bemail%5D=myemail")
>> params     = ActionController::Parameters.new(parameters)
>> params.require(:user)
=> #<ActionController::Parameters {"email"=>"myemail"} permitted: false>
>> params.require(:user).permit(:email)
=> #<ActionController::Parameters {"email"=>"myemail"} permitted: true>
#                                                                 ^
# everything else should work from this point

请注意，在获取单个属性时，不必允许使用参数，例如User.find(params[:id]).

我怎么确定这一点的？看这张表格，看到model: @user，这意味着上面的所有^.这是一个常见的问题.但您所要做的就是查看日志(log)，您可以在那里看到PARAMETERS以及浏览器中没有显示的任何错误.