Tests and fixes for the generate_etag/2 callback

The return value from the generate_etag/2 callback is expected to be a
binary tagged with either weak or strong. This binary is quoted, and
may be prefixed with W/ before it is set as the value of the ETag header
in the response.

For backwards compatibility with older handlers where the return value
was expected to be a quoted binary a function has been added to parse any
return values that are untagged binaries. All untagged binaries are expected
to be a valid value for the ETag header.

1 files changed, 30 insertions, 0 deletions

diff --git a/test/rest_resource_etags.erl b/test/rest_resource_etags.erl
new file mode 100644
index 0000000..b21aa9f
--- /dev/null
+++ b/test/rest_resource_etags.erl
@@ -0,0 +1,30 @@
+-module(rest_resource_etags).
+-export([init/3, generate_etag/2, content_types_provided/2, get_text_plain/2]).
+
+init(_Transport, _Req, _Opts) ->
+	{upgrade, protocol, cowboy_http_rest}.
+
+generate_etag(Req, State) ->
+	case cowboy_http_req:qs_val(<<"type">>, Req) of
+		%% Correct return values from generate_etag/2.
+		{<<"tuple-weak">>, Req2} ->
+			{{weak, <<"etag-header-value">>}, Req2, State};
+		{<<"tuple-strong">>, Req2} ->
+			{{strong, <<"etag-header-value">>}, Req2, State};
+		%% Backwards compatible return values from generate_etag/2.
+		{<<"binary-weak-quoted">>, Req2} ->
+			{<<"W/\"etag-header-value\"">>, Req2, State};
+		{<<"binary-strong-quoted">>, Req2} ->
+			{<<"\"etag-header-value\"">>, Req2, State};
+		%% Invalid return values from generate_etag/2.
+		{<<"binary-strong-unquoted">>, Req2} ->
+			{<<"etag-header-value">>, Req2, State};
+		{<<"binary-weak-unquoted">>, Req2} ->
+			{<<"W/etag-header-value">>, Req2, State}
+	end.
+
+content_types_provided(Req, State) ->
+	{[{{<<"text">>, <<"plain">>, []}, get_text_plain}], Req, State}.
+
+get_text_plain(Req, State) ->
+	{<<"This is REST!">>, Req, State}.