Add 'If-Match' and 'If-None-Match' to parse_header/2

2 files changed, 45 insertions, 1 deletions

diff --git a/src/cowboy_http.erl b/src/cowboy_http.erl
index 1fd220f..6d14961 100644
--- a/src/cowboy_http.erl
+++ b/src/cowboy_http.erl
@@ -17,7 +17,7 @@
 
 %% Parsing.
 -export([list/2, nonempty_list/2,
-	media_range/2, conneg/2, language_range/2,
+	media_range/2, conneg/2, language_range/2, entity_tag_match/1,
 	http_date/1, rfc1123_date/1, rfc850_date/1, asctime_date/1,
 	digits/1, token/2, token_ci/2, quoted_string/2]).
 
@@ -238,6 +238,30 @@ maybe_qparam(Data, Fun) ->
 qparam(<< Q, $=, Data/bits >>, Fun) when Q =:= $q; Q =:= $Q ->
 	qvalue(Data, Fun).
 
+%% @doc Parse either a list of entity tags or a "*".
+-spec entity_tag_match(binary()) -> any().
+entity_tag_match(<< $*, Rest/bits >>) ->
+	whitespace(Rest,
+		fun (<<>>) -> '*';
+			(_Any) -> {error, badarg}
+		end);
+entity_tag_match(Data) ->
+	nonempty_list(Data, fun entity_tag/2).
+
+%% @doc Parse an entity-tag.
+-spec entity_tag(binary(), fun()) -> any().
+entity_tag(<< "W/", Rest/bits >>, Fun) ->
+	opaque_tag(Rest, Fun, weak);
+entity_tag(Data, Fun) ->
+	opaque_tag(Data, Fun, strong).
+
+-spec opaque_tag(binary(), fun(), weak | strong) -> any().
+opaque_tag(Data, Fun, Strength) ->
+	quoted_string(Data,
+		fun (_Rest, <<>>) -> {error, badarg};
+			(Rest, OpaqueTag) -> Fun(Rest, {Strength, OpaqueTag})
+		end).
+
 %% @doc Parse an HTTP date (RFC1123, RFC850 or asctime date).
 %% @end
 %%
@@ -693,6 +717,18 @@ media_range_list_test_() ->
 	],
 	[{V, fun() -> R = list(V, fun media_range/2) end} || {V, R} <- Tests].
 
+entity_tag_match_test_() ->
+	%% {Tokens, Result}
+	Tests = [
+		{<<"\"xyzzy\"">>, [{strong, <<"xyzzy">>}]},
+		{<<"\"xyzzy\", W/\"r2d2xxxx\", \"c3piozzzz\"">>,
+			[{strong, <<"xyzzy">>},
+			 {weak, <<"r2d2xxxx">>},
+			 {strong, <<"c3piozzzz">>}]},
+		{<<"*">>, '*'}
+	],
+	[{V, fun() -> R = entity_tag_match(V) end} || {V, R} <- Tests].
+
 http_date_test_() ->
 	%% {Tokens, Result}
 	Tests = [
diff --git a/src/cowboy_http_req.erl b/src/cowboy_http_req.erl
index feb795c..12d117f 100644
--- a/src/cowboy_http_req.erl
+++ b/src/cowboy_http_req.erl
@@ -205,6 +205,8 @@ parse_header_default('Accept-Charset') -> [];
 parse_header_default('Accept-Encoding') -> [];
 parse_header_default('Accept-Language') -> [];
 parse_header_default('Connection') -> [];
+parse_header_default('If-Match') -> '*';
+parse_header_default('If-None-Match') -> '*';
 parse_header_default(_Name) -> undefined.
 
 %% @doc Semantically parse headers.
@@ -243,6 +245,12 @@ parse_header(Name, Req, Default) when Name =:= 'Content-Length' ->
 			cowboy_http:digits(Value)
 		end);
 parse_header(Name, Req, Default)
+		when Name =:= 'If-Match'; Name =:= 'If-None-Match' ->
+	parse_header(Name, Req, Default,
+		fun (Value) ->
+			cowboy_http:entity_tag_match(Value)
+		end);
+parse_header(Name, Req, Default)
 		when Name =:= 'If-Modified-Since'; Name =:= 'If-Unmodified-Since' ->
 	parse_header(Name, Req, Default,
 		fun (Value) ->