"Sun, 18 Jan 1970 21:49:31"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700118
Only TIME
21:49:31
General datetime
1970-01-18 21:49:31Z
For Database
1970-01-18 21:49:31
For HTTP1.1
Sun, 18 Jan 1970 21:49:31 GMT