formail header concatenation

Per Jessen per at
Thu Jan 22 16:02:31 CET 2009

Ruud H.G. van Tol wrote:

> AFAIK, the first whitespace character after the newline should be
> discarded, because it is the functional whitespace. In this way you
> can have a break inside long strings without any embedded whitespace.

RFC2822 only allows for folding a header line where there is whitespace,
so a long string cannot be folded in the middle:

"For convenience however, and to deal with the 998/78 character
limitations per line, the field body portion of a header field can be
split into a multiple line representation; this is called "folding". 
The general rule is that wherever this standard allows for folding
white space (not simply WSP characters), a CRLF may be inserted before
any WSP."


/Per Jessen

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