email.headerregistry.DateHeader

class email.headerregistry.DateHeader

RFC 5322 specifies a very specific format for dates within email headers. The DateHeader parser recognizes that date format, as well as recognizing a number of variant forms that are sometimes found “in the wild”.

This header type provides the following additional attributes:

datetime

If the header value can be recognized as a valid date of one form or another, this attribute will contain a datetime instance representing that date. If the timezone of the input date is specified as -0000 (indicating it is in UTC but contains no information about the source timezone), then datetime will be a naive datetime. If a specific timezone offset is found (including +0000), then datetime will contain an aware datetime that uses datetime.timezone to record the timezone offset.

The decoded value of the header is determined by formatting the datetime according to the RFC 5322 rules; that is, it is set to:

email.utils.format_datetime(self.datetime)

When creating a DateHeader, value may be datetime instance. This means, for example, that the following code is valid and does what one would expect:

msg['Date'] = datetime(2011, 7, 15, 21)

Because this is a naive datetime it will be interpreted as a UTC timestamp, and the resulting value will have a timezone of -0000. Much more useful is to use the localtime() function from the utils module:

msg['Date'] = utils.localtime()

This example sets the date header to the current time and date using the current timezone offset.