Re: luasocket: HTTP and multiple headers

[Matthew Wild <mwild1@...>]

On 13 February 2012 12:48, Vladimir Dronnikov <dronnikov@gmail.com> wrote:
> Hi!
>
> LuaSocket HTTP responses concatenate same-named headers using commas.
> This makes it practically impossible to reliably split them later in
> application logic.

Unfortunately it is well within its rights to do so. The HTTP
specification clearly states that multiple headers are equal to
comma-separated lists[1].

> Consider vanilla use case: server sets multiple
> Set-Cookie:

Yes, Set-Cookie. A few implementations quote the date in Expires, but
I don't believe that practice is widespread. Still, it's not
*impossible* to parse - you just have to treat the date as everything
between Expires= and the next ';' [2].

> I see two straight ways to fix that: either to report array-like
> tables for same-named headers, or concat using a nonce, which itself
> is reported as a key to returned response table.

Yes, this would be sensible. However I still see the possibilities of
applications then expecting an array, and then a HTTP server or proxy
sending a comma-separated list in a single header (proxies can and
will do this). Therefore it still requires knowledge (that LuaSocket
doesn't have) of whether a particular header is a list or not.

> Or, how else this problem is solved?

Backwards compatibility with the internet is fun :)

Regards,
Matthew

[1]: http://tools.ietf.org/html/rfc1945#section-4.2
[2]: http://tools.ietf.org/html/rfc6265#section-4.1.1