Module rfc2822

Available on crate features dep_jiff and alloc only.

Support for printing and parsing instants using the RFC 2822 datetime format.

RFC 2822 is most commonly found when dealing with email messages.

Since RFC 2822 only supports specifying a complete instant in time, the parser and printer in this module only use Zoned and Timestamp. If you need inexact time, you can get it from Zoned via Zoned::datetime.

Incomplete support

The RFC 2822 support in this crate is technically incomplete. Specifically, it does not support parsing comments within folding whitespace. It will parse comments after the datetime itself (including nested comments). See Issue #39 for an example. If you find a real world use case for parsing comments within whitespace at any point in the datetime string, please file an issue. That is, the main reason it isn’t currently supported is because it didn’t seem worth the implementation complexity to account for it. But if there are real world use cases that need it, then that would be sufficient justification for adding it.

RFC 2822 support should otherwise be complete, including support for parsing obselete offsets.

Warning

The RFC 2822 format only supports writing a precise instant in time expressed via a time zone offset. It does not support serializing the time zone itself. This means that if you format a zoned datetime in a time zone like America/New_York and then deserialize it, the zoned datetime you get back will be a “fixed offset” zoned datetime. This in turn means it will not perform daylight saving time safe arithmetic.

Basically, you should use the RFC 2822 format if it’s required (for example, when dealing with email). But you should not choose it as a general interchange format for new applications.

Structs

• DateTimeParser
  A parser for RFC 2822 datetimes.
• DateTimePrinter
  A printer for RFC 2822 datetimes.

Functions

• parse
  Parse an RFC 2822 datetime string into a Zoned.
• to_string
  Convert a Zoned to an RFC 2822 datetime string.