试图获取保存在隐藏字段中的current_user的值

Question

我有一个简单的rails应用程序，在其中一种形式中，我试图使用隐藏字段标记将当前用户的值保存到字段中。

我的应用程序控制器有user_authenticate方法，它也设置了@current_user的值，如下所示。

的ApplicationController

class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception
  protected 

def authenticate_user
  if session[:user_id]
     # set current user object to @current_user object variable
    @current_user = User.find session[:user_id] 
    return true 
  else
    redirect_to(:controller => 'sessions', :action => 'login')
    return false
  end
end
def save_login_state
  if session[:user_id]
    redirect_to(:controller => 'sessions', :action => 'home')
    return false
  else
    return true
  end
end

end

使用belongs_to用户定义收据模型，如下所示。

收据模型

class Receipt < ApplicationRecord
  belongs_to :currency
  belongs_to :user
end

并且表单视图的隐藏字段标记如下所示。

表格

<%= form_for(receipt) do |f| %>

  <% if receipt.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(receipt.errors.count, "error") %> prohibited this receipt from being saved:</h2>

      <ul>
      <% receipt.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>
<div align="center" style="text-align: right; width: 50%">
  <div class="field">
    <%= f.label :receipt_date %>
    <%= f.date_select :receipt_date %>
  </div>
</br>
  <div class="field">
    <%= f.label :receipt_amount %>
    <%= f.text_field :receipt_amount %>
  </div>
</br>
  <div class="field">
    <%= f.label :Currency%>
    <%= f.collection_select :currency_id, Currency.all, :id, :currency %>
  </div>
</br>
  <div class="field">
    <%= f.hidden_field :user_id, :user_id => @current_user %>
  </div>

</br>
 <div class="actions">
    <%= f.submit %>
  </div>
</div>

<% end %>

然而，当我保存记录时，我收到一个错误 - “用户必须存在”。基本上，用户字段将为'nil'。

我的收据控制器就像这样

ReceiptsController

class ReceiptsController < ApplicationController

  before_action :set_receipt, only: [:show, :edit, :update, :destroy]

  # GET /receipts
  # GET /receipts.json
  def index
    @receipts = Receipt.all
  end

  # GET /receipts/1
  # GET /receipts/1.json
  def show
  end

  # GET /receipts/new
  def new
    @receipt = Receipt.new
  end

  # GET /receipts/1/edit
  def edit
  end

  # POST /receipts
  # POST /receipts.json
  def create
    @receipt = Receipt.new(receipt_params)

    respond_to do |format|
      if @receipt.save
        format.html { redirect_to @receipt, notice: 'Receipt was successfully created.' }
        format.json { render :show, status: :created, location: @receipt }
      else
        format.html { render :new }
        format.json { render json: @receipt.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /receipts/1
  # PATCH/PUT /receipts/1.json
  def update
    respond_to do |format|
      if @receipt.update(receipt_params)
        format.html { redirect_to @receipt, notice: 'Receipt was successfully updated.' }
        format.json { render :show, status: :ok, location: @receipt }
      else
        format.html { render :edit }
        format.json { render json: @receipt.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /receipts/1
  # DELETE /receipts/1.json
  def destroy
    @receipt.destroy
    respond_to do |format|
      format.html { redirect_to receipts_url, notice: 'Receipt was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_receipt
      @receipt = Receipt.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def receipt_params
      params.require(:receipt).permit(:receipt_date, :receipt_amount, :currency_id, :user_id)
    end
end

Answer 1

如果你有设计，这应该为你做，注意非实例变量，没有@

  <div class="field">
    <%= f.hidden_field :user_id, :value => current_user.id %>
  </div>

或其他情况，在您的情况下。

  <div class="field">
    <%= f.hidden_field :user_id, :value => @current_user.id %>
  </div>

Answer 2

理想情况下，您不必在表单中呈现current_user id，您已经有一个会话来识别用户，只需将收据范围限定在收据控制器中的当前用户下：

class ReceiptsController < ApplicationController
  ...
  def create
    receipt = current_user.receipts.new(receipt_params)
    if receipt.save
      # redirect
    else
      # render new
    end
  end
end

这也可以防止未经过身份验证的用户更新其他人的收据。如果您正在对用户进行身份验证并且可以访问控制器中的当前用户，那么这就是您的选择。