Rails 4.0.4：如何顯示創建記錄是否成功？

Question

所以提交表單我Testimony模型後，我得到了下面的活動在我的rails控制檯：

Processing by TestimoniesController#create as HTML 
    Parameters: {"utf8"=>"✓", "authenticity_token"=>"Y7n/+rlDoH3ys68HMOh6T6WFpAelRT18WUPstCz41vE=", "testimony"=>{"first_name"=>"bob ", "last_name"=>"balaban", "email"=>"", "contact_number"=>"", "country"=>"", "question1"=>"", "question2"=>"", "question3"=>"", "question4"=>"", "question5"=>"", "signature"=>"", "waiver"=>"0"}, "commit"=>"Save Testimony"} 
    (0.1ms) begin transaction 
    Testimony Exists (0.2ms) SELECT 1 AS one FROM "testimonies" WHERE ("testimonies"."last_name" = 'balaban' AND "testimonies"."first_name" = 'bob ' AND "testimonies"."email" = '') LIMIT 1 
    (0.1ms) rollback 

這裏是TestimoniesController

class TestimoniesController < ApplicationController 

    def new 
    end 

    def index 
    end 

    def show 
    @testimony = Testimony.find(params[:id]) 
    end 

    def create 
    @testimony = Testimony.new(post_params) 

    @testimony.save 
    redirect_to @testimony 
    end 


    private 
    def post_params 
     params.require(:testimony).permit(:first_name, :email, :last_name, :contact_number, :country, :question1, :question2, :question3, :question4, :question5, :signature, :waiver) 
    end 
end 

這裏是我的Testimony.rb

class Testimony < ActiveRecord::Base 
    validates_presence_of :first_name, :last_name,:email, :contact_number, :country, :question1, :question2, :question3, :question4, :question5, :signature, :waiver 
    validates_uniqueness_of :last_name, :scope => [:first_name, :email] 
end 

型號文件

我想顯示一條消息，如： 已記錄已存在TS

或者 所有字段需要填寫

我意識到這是很可悲的，但我認爲這是Rails的魔法的一部分斷言所有模型的在該領域的獨特性和存在表單級別，然後再執行@ modelname.save。我顯然不是很明白。謝謝你的幫助。

Answer 1

如果@modelname.save!失敗，則會引發異常...異常名稱因您可能使用的orm而異。但最有可能它會ActiveModel::Validations

您可以使用以下方式我自己用的

@testimony.save! 
redirect_to @testimony 
rescue_from ActiveModel::Validations do |ex| 
    # here you can flash the message do what ever you want when saving fails 
    render json: {message: 'Record already exists', status: :unprocessable_entity 
end 

其他解決方法是使用下面的

if @testimony.save 
    redirect_to @testimony 
else 
    render json: {message: 'Record already exists', status: :unprocessable_entity 
end 

---

[EXTRA信息您CAN IGNORE：D]

我們e第一個解決方案，因爲我可以處理application_controller中的例外情況。

例如，你可以添加這些到application_controller處理這些失敗的案例

rescue_from CanCan::AccessDenied, with: :render_access_denied 
rescue_from Mongoid::Errors::DocumentNotFound, with: :render_not_found 
rescue_from ActionController::RoutingError, with: :render_not_found 
rescue_from(ActionController::ParameterMissing) do |parameter_missing_exception| 
    error = {} 
    error[parameter_missing_exception.param] = ['parameter is required'] 
    render_bad_request error 
end 

其中render_XXX是在應用程序控制器中定義的方法。