ruby-on-rails - 表单提交的值为 nil(缺少参数或值为空 : amount)

Question

我是 Rails 的新手，所以请原谅我。我知道我收到此错误是因为我指定了参数所需的数量。如果我不这样做，我最终会得到一个只有一个 transaction_id 而其他所有字段都为 nil 的交易条目。我相信我的问题必须处理我的路线，但我不确定出了什么问题。

我的错误:

ActionController::ParameterMissing in TransactionsController#create

param is missing or the value is empty: amount

但我可以看到正在传递字段:

     Parameters:
      {"utf8"=>"✓","authenticity_token"=>
"H+Xxpze7HWC9oduZC2CSxnWHztfhabEMRCoYy0Gw7upNknF2aIHsZ1G/xQOsICTVd7n4btqtT5760UL7QovIrA==",
"transaction"=>{"amount"=>"29", "transactionType"=>"withdraw"}, "commit"=>"Create Transaction"}

我的交易 Controller :

class TransactionsController < ApplicationController

def new
    @account = Account.find(params[:account_id]) 
    @transaction = Transaction.new
    @transaction.account_id = @account.id
end

def create 
   @transaction = Transaction.new(transactions_params)
    if @transaction.save
       redirect_to '/viewAccount/:id'
    else
        render 'new'
    end
end

private 
def transactions_params 
    params.require(:amount).permit(:account_id, :transactionType) 
end
end

我的新 View (表单):

<div class="destination">
<div class="container">
<div class = "form">
<h3>Add a new transaction for <%= current_user.email %> </h3>
<%= form_for(@transaction) do |f| %>
  <%= f.text_field :amount %>
  <%= f.select :transactionType, [['withdraw', 'withdraw'], ['deposit', 'deposit']] %>
  <%= f.submit "Create Transaction", class: "btn-submit" %>
<% end %> 
</div>
</div>
</div> 

我的路线:

Rails.application.routes.draw do
root 'mysite#index'
get 'signup' => 'users#new'
post 'signup' => 'users#create'
resources :users
get 'login' => 'sessions#new'
post 'login' => 'sessions#create'
get'newAccount' => 'accounts#new'
get 'viewAccount/:id' => 'banksite#show'
delete 'logout' => 'sessions#destroy'
get 'transactions' => 'transactions#new'
post 'transactions' => "transactions#create"
resources :transactions

银行业务查看/开始交易新

<div class=content>
<div class=main>
<h1>Welcome to Online Banking <%= current_user.email %></h1>
<p>You're only allowed to see this page if you are logged in</p>
    <h2><%= current_user.email %> 's Account Summary</h2>
    <h3>Balance: $ <%= @account.balance %> </h3>
   <%= link_to "Create Transaction", 
:controller => "transactions", 
:action => "new", 
:account_id => @account.id %>
</div>
</div>
</div>

我的模型:

class User < ActiveRecord::Base
  has_secure_password
  has_one :account
end

class Account < ActiveRecord::Base
  belongs_to :user
  has_many :transactions
end

class Transaction < ActiveRecord::Base
  belongs_to :account
end

如能深入了解此错误，我将不胜感激。

Answer 1

这个:

params.require(:amount).permit(:account_id, :transactionType)

期望参数如下:

"amount" => { "account_id" => "...", "transactionType" => "..." }

但是你的参数看起来像:

"transaction"=>{"amount"=>"29", "transactionType"=>"withdraw"}

此外，您的表单中没有account_id。

首先，您需要将 account_id 添加到您的表单中，例如:

<%= f.hidden_field :account_id %>

然后你需要在你的 Controller 中更新你的表单解析:

params.require(:transaction).permit(:account_id, :amount, :transactionType)

这样它将在顶层寻找 “transaction” 和 “account_id”、“amount” 和 “transactionType” 在里面。