Ruby/Rails: converting a Date to a UNIX timestamp

Question

How would I get a UNIX timestamp (number of seconds since 1970 GMT) from a Date object in a Rails app?

I know Time#to_i returns a timestamp, but doing <

Answer 1

The suggested options of using to_utc or utc to fix the local time offset does not work. For me I found using Time.utc() worked correctly and the code involves less steps:

> Time.utc(2016, 12, 25).to_i
=> 1482624000 # correct

vs

> Date.new(2016, 12, 25).to_time.utc.to_i
=> 1482584400 # incorrect

---

Here is what happens when you call utc after using Date....

> Date.new(2016, 12, 25).to_time
=> 2016-12-25 00:00:00 +1100 # This will use your system's time offset
> Date.new(2016, 12, 25).to_time.utc
=> 2016-12-24 13:00:00 UTC

...so clearly calling to_i is going to give the wrong timestamp.