Active Record and file: How to write a Json file with my data?

Question

How to write data in a table event to a json file? See this code:

In the event.rb model

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 

There is one entry in the Json file, but there are many entries in the event table. How to write all the records from the event table to the event.json file after saving the record?

open / event.json

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

Answer 1

The problem is that you are assigning @eventJson to the loop so that previous values ​​are lost. You should use an array:

 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 

Answer 2

In this case, you can use map instead of each - it is much cleaner. Given that you said that the method is in the model, this is how it will look.

 class Event < ActiveRecord::Base ... def self.write_json record_json = self.all.map{ |record| { self.name => record.attributes } }.to_json File.open("#{Rails.root}/#{(self.name.underscore)}.json", "w") do |f| f.write record_json end end end