Headers ordering

[eLRuLL]

In some cases headers order matter, like here

Could this be changed somehow? and why is it important to handle headers on a gb_tree structure?

[etrepum]

The gb_tree data structure is necessary for performance reasons. What's your use case? When multiple headers with the same name are present, they are combined in the order that they were received.

`> mochiweb_headers:to_list(mochiweb_headers:make([{"foo", "a"}, {"foo", "b"}])).
[{"foo","a, b"}]

[eLRuLL]

I am using mochiweb like a proxy, so I need to pass a server response to the client and the server response headers are like:

Set-Cookie: selectedCountry=US; Expires=Sat, 29 Aug 2015 15:16:49 GMT; Path=/; Domain=.example.com
Set-Cookie: selectedCountry=GB; Expires=Sat, 29 Aug 2015 15:16:49 GMT; Path=/; Domain=.example.com

but when passing through mochiweb, it returns:

Set-Cookie: selectedCountry=GB; Expires=Sat, 29 Aug 2015 15:16:49 GMT; Path=/; Domain=.example.com
Set-Cookie: selectedCountry=US; Expires=Sat, 29 Aug 2015 15:16:49 GMT; Path=/; Domain=.example.com

Which sets incorrect cookie on the client side.

[etrepum]

Order for Set-Cookie is preserved. Are you doing some sort of transformation? How exactly are you generating the headers for the response?

1> mochiweb_headers:to_list(mochiweb_headers:make([{"Set-Cookie", "selectedCountry=GB"}, {"Set-Cookie", "selectedCountry=US"}])).
[{"Set-Cookie","selectedCountry=GB"},
 {"Set-Cookie","selectedCountry=US"}]

This ordering property is tested (in a few places, here's one):

set_cookie_test() ->
    H = make([{"set-cookie", foo}, {"set-cookie", bar}, {"set-cookie", baz}]),
    ?assertEqual(
       [{"set-cookie", "foo"}, {"set-cookie", "bar"}, {"set-cookie", "baz"}],
       to_list(H)),
    ok.

[etrepum]

Ok, I found the issue, it's with formatting the headers in the response, not with mochiweb_headers itself.

[eLRuLL]

thanks for this 👍