紅寶石時區毫秒，自紀元在午夜

Question

我需要以毫秒爲單位的時間自1970年以來爲今天與BST（英國夏令時間）偏移

a = DateTime.now 
=> Fri, 29 Sep 2017 16:30:29 +0100 

b = DateTime.new(a.year, a.month, a.day, 0, 0, 0, 0) 
=> Fri, 29 Sep 2017 00:00:00 +0000 # this is an hour out 

b.strftime('%Q').to_i 
1506643200000      # therefore this is an hour out 

如何糾正呢？

b = b.in_time_zone 
=> Fri, 29 Sep 2017 01:00:00 BST +01:00 # looks promising but... 

b.strftime('%Q').to_i 
=> 0          # grrr 

任何最受歡迎的幫助

Answer 1

我發現這個解決方案：

a = DateTime.now 
=> Fri, 29 Sep 2017 16:30:29 +0100 

a = a.beginning_of_day 
=> Fri, 29 Sep 2017 00:00:00 +0100 

milliseconds_since_1970 = a.to_i * 1000 
=> 1506639600000      <-- correct!