[Web-SIG] Why is response_headers a list instead of a dict?

[James Y Knight]

On Dec 24, 2005, at 10:45 PM, Clark C. Evans wrote:

> Why is response_headers a list instead of a dict?
>
> [ RFC quote ]
>
> In other words: (a) order does not matter

True, order between headers does not matter.

> (b) it is reasonable to
> restrict a header field to a single (header_name, header_value) pair.

Yes, the RFC says that, and I certainly wish it were true, but it's  
simply not. The RFC lies. The primary example is the Set-Cookie  
header, which by _definition_ cannot be combined, as it uses an  
unquoted date which includes a comma. Also, multiple WWW-Authenticate  
headers should be okay to combine, but I've heard rumors of UAs being  
confused by that format.

WSGI could have spec'd a dictionary of lists of strings, rather than  
a list of strings, but it did not. You can transform the result into  
that if you like...

James