Headers with the same name get joined by comma that leads to confusion

[kompot]

Given the following HTTP response

Set-Cookie: cookie_key_1=yyy; Path=/
Set-Cookie: cookie_key_2=xxx; expires=Mon, 17-Oct-2016 17:16:25 GMT; httponly; Max-Age=1209600; Path=/

Headers object is the following:

headers: {
  ...
  'set-cookie': 'cookie_key_1=yyy; Path=/, cookie_key_2=xxx; expires=Mon, 17-Oct-2016 17:16:25 GMT; httponly; Max-Age=1209600; Path=/'
  ...
}

Seems like broken behaviour to me as it's not possible to split cookies into separate objects.
One of the solutions might be returning array in this case.

[rubennorte]

It isn't a broken behaviour. It's the behaviour defined by the HTTP standard (where any header allowed to have multiple values can be specified either as multiple headers or as a single header with comma-separated values).

We could return an array instead of combining the values, but that would be an important breaking change for the library and wouldn't prevent a server from sending a comma-separated Set-Cookie header (which is perfectly valid).

[rubennorte]

I'm sorry but I read the standard for HTTP State Management and it states that Set-Cookie cannot be folded as I explained:

Origin servers SHOULD NOT fold multiple Set-Cookie header fields into a single header field. The usual mechanism for folding HTTP headers fields (i.e., as defined in [RFC2616]) might change the semantics of the Set-Cookie header field because the %x2C (",") character is used by Set-Cookie in a way that conflicts with such folding.

This is actually a bug. We'll look into it or will be happy to accept a PR.

Thanks for reporting!

[jcready]

Why not simply copy the Headers interface?

res.headers.get('set-cookie') // Returns "cookie_key_1=yyy; Path=/"
res.headers.getAll('set-cookie') // Returns [ "cookie_key_1=yyy; Path=/", "cookie_key_2=xxx; expires=Mon, 17-Oct-2016 17:16:25 GMT; httponly; Max-Age=1209600; Path=/" ]

You could also maintain the existing API, but also provide the getAll method.

res.headers['set-cookie'] // Returns "cookie_key_1=yyy; Path=/"
res.headers.getAll('set-cookie') // Returns [ "cookie_key_1=yyy; Path=/", "cookie_key_2=xxx; expires=Mon, 17-Oct-2016 17:16:25 GMT; httponly; Max-Age=1209600; Path=/" ]