如何在MongoMapper& Ruby / Rails？ [英] How to convert Date into UTC in MongoMapper & Ruby/Rails?

问题描述

我添加了这行代码

self.auth_history.push [start_date, self.coupon_code]

并收到此错误消息

Date is not currently supported; use a UTC Time instance instead.

我也尝试过 start_date.utc 它也没有工作。

I also tried start_date.utc, but it didn't work either.

请帮忙。谢谢。

推荐答案

我得到了西雅图旅团队的答案 -

I got this answer from Seattle Brigade group -

===

我没有看到你的代码中定义的start_date是MongoMapper中的一个关键字，所以
我假设你正在创建自己的日期对象，直接通过Ruby，
或由Rails包装。据我所知，有人请更正我，Mongo
以UTC为单位，以UTC为单位存储日期。所以当你在MongoMapper中定义一个
键时，你可以在
Ruby中包含一个Time对象。

I didn't see start_date defined in your code as a key in MongoMapper, so I'll assume you're creating your own date object, either directly via Ruby, or wrapped by Rails. As far as I know, and someone please correct me, Mongo stores dates as UTC time in milliseconds since epoch. So when you define a key with a :date mapping in MongoMapper, you're wrapping a Time object in Ruby.

因此，如果你想在Mongo中存储一个日期，而不是由MongoMapper创建的
，请确保在UTC中创建一个Time对象。
MongoMapper附带一个名为to_mongo的Date mixin方法，您可以使用它。

Therefore, if you want to store a date inside of Mongo, and it wasn't created by MongoMapper, make sure you create a Time object in UTC. MongoMapper comes with a Date mixin method called to_mongo that you can use.

>> Time.now.utc
=> Fri Jan 28 03:47:50 UTC 2011
>> require 'date'
=> true
>> date = Date.today
=> #<Date: 4911179/2,0,2299161>
>> Time.utc(date.year, date.month, date.day)
=> Thu Jan 27 00:00:00 UTC 2011
>> require 'rubygems'
=> true
>> require 'mongo_mapper'
=> true
>> Date.to_mongo(date)
=> Thu Jan 27 00:00:00 UTC 2011

但请注意时间的变化。 >

But watch out for the time change.

>> Date.to_mongo(Time.now)
=> Thu Jan 27 00:00:00 UTC 2011
>> Date.to_mongo(Time.now.utc)
=> Fri Jan 28 00:00:00 UTC 2011

祝你好运。

===

并使用

Date.to_mongo(start_date) 

它适用于我。

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