Question

My goal is to get a Time instance from a DateTime instance

This has been previously discussed here and I am still confused : Convert to/from DateTime and Time in Ruby

For me in irb running ruby 1.9.3p0 (2011-10-30 revision 33570) [x86_64-darwin11.2.0], things work perfectly

1.9.3p0 :001 > require 'Date'
 => true 
1.9.3p0 :002 > require 'Time'
 => true 
1.9.3p0 :003 > t=DateTime.now
 => #<DateTime: 2012-07-01T01:57:32+05:30 ((2456109j,73652s,621060000n),+19800s,2299161j)> 
1.9.3p0 :004 > t2=t.to_time
 => 2012-07-01 01:57:32 +0530 
1.9.3p0 :005 > t.class
 => DateTime 
1.9.3p0 :006 > t2.class
 => Time 
1.9.3p0 :007 > 

However when working with rails console v 3.2.3 on same ruby platform

1.9.3p0 :001 > t=DateTime.now
 => Sun, 01 Jul 2012 02:00:00 +0530 
1.9.3p0 :002 > t.class
 => DateTime 
1.9.3p0 :003 > t2=t.to_time
 => Sun, 01 Jul 2012 02:00:00 +0530
1.9.3p0  > t2.class
 => DateTime

What to do to get a Time instance from DateTime in rails?

Answer 1

According to the Rails documentation for DateTime.to_time(),

If self has an offset other than 0, self will just be returned unaltered

To change to a 0 offset, use DateTime.utc().

1.9.3p194 :005 > t3=t2.utc
 => Sat, 30 Jun 2012 20:43:21 +0000 
1.9.3p194 :006 > t3.offset
 => (0/1) 
1.9.3p194 :007 > t4=t3.to_time
 => 2012-06-30 20:43:21 UTC 
1.9.3p194 :008 > t4.class
 => Time