[Imap-protocol] folding/encoding of subject in ENVELOPE

[Timo Sirainen]

On 10.7.2010, at 4.00, Mark Crispin wrote:


> On Fri, 9 Jul 2010, Lyndon Nerenberg wrote:

>>> Yes, but my server (and many others) are converting all whitespace to a

>>> single space (tabs, folds, multiple spaces, etc). I can't exactly

>>> remember why, though. Maybe I implemented it only because others did

>>> that too..

>> The '822 <FWS> grammar production.

> 

> Correct.  You interpret the fields as per RFC 822 (etc.).

> 

> Line folding is an RFC 822 (etc.) concept and is not part of the field

> data (e.g., Subject).  Header fields are logically a single line, even if

> they are multiple lines in the header.


But it's not just the line folding. All LWSP containing tabs, spaces and CRLFs are converted into a single space by many servers (IIRC also UW-IMAP). RFC 822 says that all LWSP is equivalent to a single space in structured fields, but subject is unstructured field.


> Arguably, a future version of IMAP should decode MIME encoded-words into

> UTF-8.


I'm looking forward to RFC 5738bis.