ruby-on-rails - 事件记录和文件 : How do i write Json file with my data?

Question

如何将表事件中的数据写入json文件？请看这段代码:

在模型 event.rb 中

 class Event < ActiveRecord::Base
  attr_accessible :name, :event_description, :start_at, :end_at, :status, :eventable_id
  has_event_calendar
  belongs_to :eventable, polymorphic: true
  after_save :write_json


end
def write_json
    Event.all.each do |event|
            @eventJson = {
            "id" => event.id,
            "start" => event.start_at,
            "end" => event.end_at,
            "title" => event.name,
            "body" => event.event_description,
            "status" => event.status
            } 

    end
    File.open("public/event.json","w") do |f|
      f.write(@eventJson.to_json)
    end 

 end

在文件Json中只有一条记录，但是在表event中有很多条记录。如何在保存记录后将event表中的所有记录写入event.json文件？

公共(public)/事件.json

{"id":35,"start":"2013-03-28T00:00:00Z","end":"2013-03-28T00:00:00Z","title":"1345edrewrewr","body":"123124","status":"Confirm"}

Answer 1

问题是您在循环中为 @eventJson 赋值，因此先前的值会丢失。你应该使用一个数组:

def write_json
  events_json = []
  Event.all.each do |event|
    event_json = {
      "id" => event.id,
      "start" => event.start_at,
      "end" => event.end_at,
      "title" => event.name,
      "body" => event.event_description,
      "status" => event.status
    } 
    events_json << event_json
  end
  File.open("public/event.json","w") do |f|
    f.write(events_json.to_json)
  end 
end