Add cow_http_hd:parse_host/1, remove cow_http:parse_fullhost/1

From RFC7230 and RFC3986.

The new function now validates that the characters are correct,
but does not go as far as validate segment sizes or number of
segments. Its main purpose is still to split host and port.

1 files changed, 91 insertions, 0 deletions

diff --git a/src/cow_http_hd.erl b/src/cow_http_hd.erl
index 848b8c9..bd0a258 100644
--- a/src/cow_http_hd.erl
+++ b/src/cow_http_hd.erl
@@ -32,6 +32,7 @@
 -export([parse_etag/1]).
 -export([parse_expect/1]).
 -export([parse_expires/1]).
+-export([parse_host/1]).
 -export([parse_if_match/1]).
 -export([parse_if_modified_since/1]).
 -export([parse_if_none_match/1]).
@@ -1846,6 +1847,96 @@ horse_parse_expires_invalid() ->
 	).
 -endif.
 
+%% @doc Parse the Host header.
+%%
+%% We only seek to have legal characters and separate the
+%% host and port values. The number of segments in the host
+%% or the size of each segment is not checked.
+%%
+%% There is no way to distinguish IPv4 addresses from regular
+%% names until the last segment is reached therefore we do not
+%% differentiate them.
+%%
+%% The following valid hosts are currently rejected: IPv6
+%% addresses with a zone identifier; IPvFuture addresses;
+%% and percent-encoded addresses.
+
+-spec parse_host(binary()) -> {binary(), 0..65535 | undefined}.
+parse_host(<< $[, R/bits >>) ->
+	ipv6_address(R, << $[ >>);
+parse_host(Host) ->
+	reg_name(Host, <<>>).
+
+ipv6_address(<< $] >>, IP) -> {<< IP/binary, $] >>, undefined};
+ipv6_address(<< $], $:, Port/bits >>, IP) -> {<< IP/binary, $] >>, binary_to_integer(Port)};
+ipv6_address(<< C, R/bits >>, IP) when ?IS_HEX(C) orelse C =:= $: orelse C =:= $. ->
+	case C of
+		?INLINE_LOWERCASE(ipv6_address, R, IP)
+	end.
+
+reg_name(<<>>, Name) -> {Name, undefined};
+reg_name(<< $:, Port/bits >>, Name) -> {Name, binary_to_integer(Port)};
+reg_name(<< C, R/bits >>, Name) when ?IS_URI_UNRESERVED(C) orelse ?IS_URI_SUB_DELIMS(C) ->
+	case C of
+		?INLINE_LOWERCASE(reg_name, R, Name)
+	end.
+
+-ifdef(TEST).
+host_chars() -> "!$&'()*+,-.0123456789;=ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz~".
+host() -> vector(1, 255, elements(host_chars())).
+
+host_port() ->
+	?LET({Host, Port},
+		{host(), oneof([undefined, int(1, 65535)])},
+		begin
+			HostBin = list_to_binary(Host),
+			{{?INLINE_LOWERCASE_BC(HostBin), Port},
+				case Port of
+					undefined -> HostBin;
+					_ -> << HostBin/binary, $:, (integer_to_binary(Port))/binary >>
+				end}
+		end).
+
+prop_parse_host() ->
+	?FORALL({Res, Host}, host_port(), Res =:= parse_host(Host)).
+
+parse_host_test_() ->
+	Tests = [
+		{<<>>, {<<>>, undefined}},
+		{<<"www.example.org:8080">>, {<<"www.example.org">>, 8080}},
+		{<<"www.example.org">>, {<<"www.example.org">>, undefined}},
+		{<<"192.0.2.1:8080">>, {<<"192.0.2.1">>, 8080}},
+		{<<"192.0.2.1">>, {<<"192.0.2.1">>, undefined}},
+		{<<"[2001:db8::1]:8080">>, {<<"[2001:db8::1]">>, 8080}},
+		{<<"[2001:db8::1]">>, {<<"[2001:db8::1]">>, undefined}},
+		{<<"[::ffff:192.0.2.1]:8080">>, {<<"[::ffff:192.0.2.1]">>, 8080}},
+		{<<"[::ffff:192.0.2.1]">>, {<<"[::ffff:192.0.2.1]">>, undefined}}
+	],
+	[{V, fun() -> R = parse_host(V) end} || {V, R} <- Tests].
+-endif.
+
+-ifdef(PERF).
+horse_parse_host_blue_example_org() ->
+	horse:repeat(200000,
+		parse_host(<<"blue.example.org:8080">>)
+	).
+
+horse_parse_host_ipv4() ->
+	horse:repeat(200000,
+		parse_host(<<"192.0.2.1:8080">>)
+	).
+
+horse_parse_host_ipv6() ->
+	horse:repeat(200000,
+		parse_host(<<"[2001:db8::1]:8080">>)
+	).
+
+horse_parse_host_ipv6_v4() ->
+	horse:repeat(200000,
+		parse_host(<<"[::ffff:192.0.2.1]:8080">>)
+	).
+-endif.
+
 %% @doc Parse the If-Match header.
 
 -spec parse_if_match(binary()) -> '*' | [etag()].