"Sun, 18 Jan 1970 18:03:42"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700118
Only TIME
18:03:42
General datetime
1970-01-18 18:03:42Z
For Database
1970-01-18 18:03:42
For HTTP1.1
Sun, 18 Jan 1970 18:03:42 GMT