Manlio Perillo wrote:
> The HTTP 1.1 protocol (section 4.2) says that:
> """Multiple message-header fields with the same field-name MAY be
> present in a message if and only if the entire field-value for that
> header field is defined as a comma-separated list [i.e., #(values)]."""
>
> This can happen, as an example, with the Cookie header.
>
> My question is: how should this be handled in WSGI?
>
> As an example Nginx stores all the headers in a associative array,
> where, of course, only the "last seen" headers appears.
>
> However common multiple message-headers are stored in the request struct.
>
> Since the WSGI environment is a dictionary with keys and values of type
> str, should an implementation:
> """combine the multiple header fields into one "field-name: field-value"
> pair, without changing the semantics of the message, by appending each
> subsequent field-value to the first, each separated by a comma."""
> ?
Yes, it should. As you note, it's part of the HTTP spec that such headers
can be combined without changing the semantics. Here's a list of the
headers that need to be folded:
comma_separated_headers = ['ACCEPT', 'ACCEPT-CHARSET', 'ACCEPT-ENCODING',
'ACCEPT-LANGUAGE', 'ACCEPT-RANGES', 'ALLOW', 'CACHE-CONTROL',
'CONNECTION', 'CONTENT-ENCODING', 'CONTENT-LANGUAGE', 'EXPECT',
'IF-MATCH', 'IF-NONE-MATCH', 'PRAGMA', 'PROXY-AUTHENTICATE', 'TE',
'TRAILER', 'TRANSFER-ENCODING', 'UPGRADE', 'VARY', 'VIA', 'WARNING',
'WWW-AUTHENTICATE']
The only tricky one is Cookie, because e.g. Konqueror sends them on
multiple lines, but they're not foldable.
See http://kristol.org/cookie/errata.html
> Ngins does not do this (and I don't know what Apache does).
>
>
> Another question: when an header has an empty field value, what should
> be set in the environment: an empty string or None?
An empty string, or omit them entirely:
"""The following variables must be present, unless their value would
be an empty string, in which case they may be omitted, except as
otherwise noted below...
HTTP_ Variables
""".
Robert Brewer
[EMAIL PROTECTED]
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