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%% Copyright (c) 2011, Loïc Hoguin <[email protected]>
%%
%% Permission to use, copy, modify, and/or distribute this software for any
%% purpose with or without fee is hereby granted, provided that the above
%% copyright notice and this permission notice appear in all copies.
%%
%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-module(cowboy_http).
%% Parsing.
-export([parse_tokens_list/1]).
%% Interpretation.
-export([connection_to_atom/1]).
-include("include/http.hrl").
-include_lib("eunit/include/eunit.hrl").
%% Parsing.
%% @doc Parse a list of tokens, as is often found in HTTP headers.
%%
%% From the RFC:
%% <blockquote>Wherever this construct is used, null elements are allowed,
%% but do not contribute to the count of elements present.
%% That is, "(element), , (element) " is permitted, but counts
%% as only two elements. Therefore, where at least one element is required,
%% at least one non-null element MUST be present.</blockquote>
-spec parse_tokens_list(binary()) -> [binary()] | {error, badarg}.
parse_tokens_list(Value) ->
case parse_tokens_list(Value, ws_or_sep, <<>>, []) of
{error, badarg} ->
{error, badarg};
L when length(L) =:= 0 ->
{error, badarg};
L ->
lists:reverse(L)
end.
-spec parse_tokens_list(binary(), token | ws | ws_or_sep, binary(),
[binary()]) -> [binary()] | {error, badarg}.
parse_tokens_list(<<>>, token, Token, Acc) ->
[Token|Acc];
parse_tokens_list(<< C, Rest/bits >>, token, Token, Acc)
when C =:= $\s; C =:= $\t ->
parse_tokens_list(Rest, ws, <<>>, [Token|Acc]);
parse_tokens_list(<< $,, Rest/bits >>, token, Token, Acc) ->
parse_tokens_list(Rest, ws_or_sep, <<>>, [Token|Acc]);
parse_tokens_list(<< C, Rest/bits >>, token, Token, Acc) ->
parse_tokens_list(Rest, token, << Token/binary, C >>, Acc);
parse_tokens_list(<< C, Rest/bits >>, ws, <<>>, Acc)
when C =:= $\s; C =:= $\t ->
parse_tokens_list(Rest, ws, <<>>, Acc);
parse_tokens_list(<< $,, Rest/bits >>, ws, <<>>, Acc) ->
parse_tokens_list(Rest, ws_or_sep, <<>>, Acc);
parse_tokens_list(<<>>, ws_or_sep, <<>>, Acc) ->
Acc;
parse_tokens_list(<< C, Rest/bits >>, ws_or_sep, <<>>, Acc)
when C =:= $\s; C =:= $\t ->
parse_tokens_list(Rest, ws_or_sep, <<>>, Acc);
parse_tokens_list(<< $,, Rest/bits >>, ws_or_sep, <<>>, Acc) ->
parse_tokens_list(Rest, ws_or_sep, <<>>, Acc);
parse_tokens_list(<< C, Rest/bits >>, ws_or_sep, <<>>, Acc) ->
parse_tokens_list(Rest, token, << C >>, Acc);
parse_tokens_list(_Value, _State, _Token, _Acc) ->
{error, badarg}.
%% Interpretation.
%% @doc Walk through a tokens list and return whether
%% the connection is keepalive or closed.
-spec connection_to_atom([binary()]) -> keepalive | close.
connection_to_atom([]) ->
keepalive;
connection_to_atom([<<"keep-alive">>|_Tail]) ->
keepalive;
connection_to_atom([<<"close">>|_Tail]) ->
close;
connection_to_atom([Connection|Tail]) ->
case cowboy_bstr:to_lower(Connection) of
<<"close">> -> close;
<<"keep-alive">> -> keepalive;
_Any -> connection_to_atom(Tail)
end.
%% Tests.
-ifdef(TEST).
parse_tokens_list_test_() ->
%% {Value, Result}
Tests = [
{<<>>, {error, badarg}},
{<<" ">>, {error, badarg}},
{<<" , ">>, {error, badarg}},
{<<",,,">>, {error, badarg}},
{<<"a b">>, {error, badarg}},
{<<"a , , , ">>, [<<"a">>]},
{<<" , , , a">>, [<<"a">>]},
{<<"a, , b">>, [<<"a">>, <<"b">>]},
{<<"close">>, [<<"close">>]},
{<<"keep-alive, upgrade">>, [<<"keep-alive">>, <<"upgrade">>]}
],
[{V, fun() -> R = parse_tokens_list(V) end} || {V, R} <- Tests].
connection_to_atom_test_() ->
%% {Tokens, Result}
Tests = [
{[<<"close">>], close},
{[<<"ClOsE">>], close},
{[<<"Keep-Alive">>], keepalive},
{[<<"Keep-Alive">>, <<"Upgrade">>], keepalive}
],
[{lists:flatten(io_lib:format("~p", [T])),
fun() -> R = connection_to_atom(T) end} || {T, R} <- Tests].
-endif.
|
