Re: [Sip-implementors] MSRP SEND's CPIM From header - display name in URI

[Paul Kyzivat]

On 9/4/18 1:56 PM, Nancy Greene wrote:

This question came up when we started to look at display name in a CPIM From header of an 
MSRP SEND (RFC4975):  If you put quotes around a display name (called Formal-name in 
RFC3862), then you do NOT put a space after the end quote and the "<" of the 
URI.


From RFC3862, the definition of 
From is:

From-header = "From" ": " [ Formal-name ] "<" URI ">"
 ; "From" is case-sensitive

In the ABNF the definition of Formal-name is:
Formal-name  = 1*( Token SP ) / String
String   = DQUOTE *( Str-char / Escape ) DQUOTE
Token= 1*TOKENCHAR

So, if the Formal-name starts with double quotes (") there is no space (SP) between the last double 
quote and the angle brackets in starting the URI. As such, the values should be: Alice 
   or   "Alice"

This is probably a tiny oversight in RFC3862, but I guess we are not going to 
update the RFC - has anyone come across this before?


I guess we can question whether this is an oversight or intentional. (I 
don't recall, but I would guess an oversight.) There are no examples 
with a quoted Formal-name to confirm the intent.


This was "patterned" after From in SIP, but it diverges in several ways. 
3261 is quite free with whitespace, whereas this is strict about it. 
Also there is the case-sensitivity of "From", if you believe the the 
comment in the ABNF is normative.


I doubt there will be a bis, but you could initiate an update if you 
feel it is important.


I would recommend that implementations strictly follow the syntax in 
what the generate, but be looser in what they accept, around whitespace 
and case-sensitivity.


Thanks,
Paul
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[Sip-implementors] MSRP SEND's CPIM From header - display name in URI

[Nancy Greene]

This question came up when we started to look at display name in a CPIM From 
header of an MSRP SEND (RFC4975):  If you put quotes around a display name 
(called Formal-name in RFC3862), then you do NOT put a space after the end 
quote and the "<" of the URI.

>From RFC3862, the definition of 
>From is:
From-header = "From" ": " [ Formal-name ] "<" URI ">"
; "From" is case-sensitive

In the ABNF the definition of Formal-name is:
Formal-name  = 1*( Token SP ) / String
String   = DQUOTE *( Str-char / Escape ) DQUOTE
Token= 1*TOKENCHAR

So, if the Formal-name starts with double quotes (") there is no space (SP) 
between the last double quote and the angle brackets in starting the URI. As 
such, the values should be: Aliceor   
"Alice"

This is probably a tiny oversight in RFC3862, but I guess we are not going to 
update the RFC - has anyone come across this before?

Nancy

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