Rails 应用中未生成表单错误消息

Question

您好，我正在构建一个简单的应用程序，当有人在字段中输入无效信息或根本没有输入任何信息时，无法显示错误消息。

我使用的表格是注册一个新用户，与用户和表格关联的代码如下；

users_controller.rb

Class UsersController < ApplicationController


  def index
    @users = User.all
  end

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

  def new
    @user = User.new
  end

  def create
    @user = User.new(user_params)
    if @user.save
      session[:user_id] = @user.id
      redirect_to @user
    else
      redirect_to '/signup'
    end
  end


  private 

    def user_params
        params.require(:user).permit(:first_name, :last_name, :email, :password)
    end


end

user.rb

class User < ApplicationRecord

  before_save { self.email = email.downcase }
  validates :first_name, presence: true, length: { maximum: 25 }
  validates :first_name, presence: true, length: { maximum: 50 }
  VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-]+(\.[a-z\d\-]+)*\.[a-z]+\z/i
  validates :email, presence: true, length: { maximum: 255 }, format: { with: VALID_EMAIL_REGEX }
  has_secure_password
  validates :password, presence: true, length: { minimum: 6 }

  has_many :trips
  has_many :countries, through: :trips

end

new.html.erb

<div class="container">
  <h1 class="text-center">Sign up</h1>
  <div class="row">
    <div class="col-md-6 offset-md-3 ">
      <%=form_for(@user) do |f| %>
        <%= render 'shared/error_messages' %>

        <%= f.label :first_name %>
        <%= f.text_field :first_name, class: "form-control" %>

        <%= f.label :last_name %>
        <%= f.text_field :last_name, class: "form-control" %>

        <%= f.label :email %>
        <%= f.email_field :email, class: "form-control" %>

        <%= f.label :password %>
        <%= f.password_field :password, class: "form-control" %>

        <%= f.submit "Create an account", class: 'form-control btn btn-primary' %>
      <% end %> 
    </div>
  </div>
</div>

_error_messages.html.erb

<% if @user.errors.any? %>
  <div class="alert alert-danger">
    The form contains <%= pluralize(@user.errors.count, "error") %>.
  </div>
  <ul>
  <% @user.errors.full_messages.each do |msg| %>
    <li><%= msg %></li>
  <% end %>
  </ul>
<% else %>
  <h3>test</h3>
<% end %>

当我加载表单时，我确实看到了 "Test" 字符串，我将其放入 _error_messages.html.erb 以提高可见性。但是，当我在注册页面中输入数据时，它会重新加载页面（当所有字段都有效时，它应该重新加载而不是将其发送到用户页面）。但是，"Test" 字符串仍然出现在顶部，而不是应该出现的错误消息。

我的假设是我需要某种会话或某种东西来记住错误是什么，因为现在它会重新加载一个全新的页面，内存中没有任何内容，但是，我目前无法在任何地方找到解决方案.

如有任何帮助，我们将不胜感激！

Answer 1

正如我所说，你需要改变

redirect_to '/signup'

到

render 'new'

来自Guides

The render method is used so that the @user object is passed back to the new template when it is rendered. This rendering is done within the same request as the form submission, whereas the redirect_to will tell the browser to issue another request.

也就是说，当 redirect_to 向浏览器发出 新请求 时， @user 的值将丢失，换句话说 @user是重新实例化的新实例。这就是为什么 <% if @user.errors.any? %> 总是 returns false 就好像 @user.

没有错误一样

Rails 应用中未生成表单错误消息

Form Error Messages Not Generating in Rails App

ruby

forms

model

ruby-on-rails

error-messaging