Merge pull request #13 from inaka/elbrujohalcon.13.add__patch__to_the…

…_allowed_met

Add 'patch' to the allowed methods in atom_to_method

src/sr_entities_handler.erl

@@ -131,8 +131,9 @@ announce_req(Req, _Opts) -> Req.
 %%% Auxiliary Functions
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
--spec atom_to_method(get|put|post|delete) -> binary().
+-spec atom_to_method(get|patch|put|post|delete) -> binary().
 atom_to_method(get) -> <<"GET">>;
+atom_to_method(patch) -> <<"PATCH">>;
 atom_to_method(put) -> <<"PUT">>;
 atom_to_method(post) -> <<"POST">>;
 atom_to_method(delete) -> <<"DELETE">>.

src/sr_single_entity_handler.erl

@@ -15,6 +15,7 @@
         , content_types_accepted/2
         , handle_get/2
         , handle_put/2
+        , handle_patch/2
         , delete_resource/2
         ]).
 
@@ -53,7 +54,9 @@ resource_exists(Req, State) ->
 -spec content_types_accepted(cowboy_req:req(), state()) ->
   {[{{binary(), binary(), '*'}, atom()}], cowboy_req:req(), state()}.
 content_types_accepted(Req, State) ->
-  {[{{<<"application">>, <<"json">>, '*'}, handle_put}], Req, State}.
+  {Method, Req1} = cowboy_req:method(Req),
+  Function = method_function(Method),
+  {[{{<<"application">>, <<"json">>, '*'}, Function}], Req1, State}.
 
 -spec handle_get(cowboy_req:req(), state()) ->
   {iodata(), cowboy_req:req(), state()}.
@@ -62,14 +65,28 @@ handle_get(Req, State) ->
   ResBody = sr_json:encode(Model:to_json(Entity)),
   {ResBody, Req, State}.
 
+-spec handle_patch(cowboy_req:req(), state()) ->
+  {{true, binary()} | false | halt, cowboy_req:req(), state()}.
+handle_patch(Req, #{entity := Entity} = State) ->
+  #{opts := #{model := Model}} = State,
+  try
+    {ok, Body, Req1} = cowboy_req:body(Req),
+    Json             = sr_json:decode(Body),
+    persist(Model:update(Entity, Json), Req1, State)
+  catch
+    _:badjson ->
+      Req3 = cowboy_req:set_resp_body(<<"Malformed JSON request">>, Req),
+      {false, Req3, State}
+  end.
+
 -spec handle_put(cowboy_req:req(), state()) ->
   {{true, binary()} | false | halt, cowboy_req:req(), state()}.
 handle_put(Req, #{entity := Entity} = State) ->
   #{opts := #{model := Model}} = State,
   try
     {ok, Body, Req1} = cowboy_req:body(Req),
     Json             = sr_json:decode(Body),
-    handle_put(Model:update(Entity, Json), Req1, State)
+    persist(Model:update(Entity, Json), Req1, State)
   catch
     _:badjson ->
       Req3 = cowboy_req:set_resp_body(<<"Malformed JSON request">>, Req),
@@ -80,7 +97,7 @@ handle_put(Req, #{id := Id} = State) ->
   try
     {ok, Body, Req1} = cowboy_req:body(Req),
     Json             = sr_json:decode(Body),
-    handle_put(from_json(Model, Id, Json), Req1, State)
+    persist(from_json(Model, Id, Json), Req1, State)
   catch
     _:badjson ->
       Req3 = cowboy_req:set_resp_body(<<"Malformed JSON request">>, Req),
@@ -103,12 +120,16 @@ from_json(Model, Id, Json) ->
     _:undef -> Model:from_json(Json)
   end.
 
-handle_put({error, Reason}, Req, State) ->
+persist({error, Reason}, Req, State) ->
   Req1 = cowboy_req:set_resp_body(Reason, Req),
   {false, Req1, State};
-handle_put({ok, Entity}, Req1, State) ->
+persist({ok, Entity}, Req1, State) ->
   #{opts := #{model := Model}} = State,
   PersistedEntity = sumo:persist(Model, Entity),
   ResBody = sr_json:encode(Model:to_json(PersistedEntity)),
   Req2 = cowboy_req:set_resp_body(ResBody, Req1),
   {true, Req2, State}.
+
+-spec method_function(binary()) -> atom().
+method_function(<<"PUT">>) -> handle_put;
+method_function(<<"PATCH">>) -> handle_patch.

test/sr_elements_SUITE.erl

@@ -69,9 +69,10 @@ success_scenario(_Config) ->
     sr_test_utils:api_call(
       put, "/elements/element1", Headers,
       #{ key => <<"element1">>
-       , value => <<"newval1">>
+       , value => <<"newval3">>
        }),
   #{ <<"key">>        := <<"element1">>
+   , <<"value">>      := <<"newval3">>
    , <<"created_at">> := CreatedAt
    , <<"updated_at">> := UpdatedAt
    } = Element3 = sr_json:decode(Body3),
@@ -82,40 +83,57 @@ success_scenario(_Config) ->
     sr_test_utils:api_call(get, "/elements"),
   [Element3] = sr_json:decode(Body4),
 
+  ct:comment("The element value can be changed by PATCH"),
+  #{status_code := 200, body := Body5} =
+    sr_test_utils:api_call(
+      patch, "/elements/element1", Headers, #{value => <<"newval5">>}),
+  #{ <<"key">>        := <<"element1">>
+   , <<"value">>      := <<"newval5">>
+   , <<"created_at">> := CreatedAt
+   , <<"updated_at">> := UpdatedAt5
+   } = Element5 = sr_json:decode(Body5),
+  true = UpdatedAt5 >= CreatedAt,
+
+  ct:comment("Still just one element"),
+  #{status_code := 200, body := Body6} =
+    sr_test_utils:api_call(get, "/elements"),
+  [Element5] = sr_json:decode(Body6),
+
   ct:comment("Elements can be created by PUT"),
-  #{status_code := 201, body := Body5} =
+  #{status_code := 201, body := Body7} =
     sr_test_utils:api_call(
       put, "/elements/element2", Headers,
       #{ key => <<"element2">>
        , value => <<"val2">>
        }),
   #{ <<"key">>        := <<"element2">>
-   , <<"created_at">> := CreatedAt5
-   , <<"updated_at">> := CreatedAt5
-   } = Element5 = sr_json:decode(Body5),
-  true = CreatedAt5 >= CreatedAt,
+   , <<"value">>      := <<"val2">>
+   , <<"created_at">> := CreatedAt7
+   , <<"updated_at">> := CreatedAt7
+   } = Element7 = sr_json:decode(Body7),
+  true = CreatedAt7 >= CreatedAt,
 
   ct:comment("There are two elements now"),
-  #{status_code := 200, body := Body6} =
+  #{status_code := 200, body := Body8} =
     sr_test_utils:api_call(get, "/elements"),
-  [Element5] = sr_json:decode(Body6) -- [Element3],
+  [Element7] = sr_json:decode(Body8) -- [Element5],
 
   ct:comment("Element1 is deleted"),
   #{status_code := 204} = sr_test_utils:api_call(delete, "/elements/element1"),
 
   ct:comment("One element again"),
-  #{status_code := 200, body := Body7} =
+  #{status_code := 200, body := Body9} =
     sr_test_utils:api_call(get, "/elements"),
-  [Element5] = sr_json:decode(Body7),
+  [Element7] = sr_json:decode(Body9),
 
   ct:comment("DELETE is not idempotent"),
   #{status_code := 204} = sr_test_utils:api_call(delete, "/elements/element2"),
   #{status_code := 404} = sr_test_utils:api_call(delete, "/elements/element2"),
 
   ct:comment("There are no elements"),
-  #{status_code := 200, body := Body8} =
+  #{status_code := 200, body := Body10} =
     sr_test_utils:api_call(get, "/elements"),
-  [] = sr_json:decode(Body8),
+  [] = sr_json:decode(Body10),
 
   {comment, ""}.
 
@@ -181,12 +199,16 @@ invalid_parameters(_Config) ->
     sr_test_utils:api_call(put, "/elements/nobody", Headers, <<>>),
   #{status_code := 400} =
     sr_test_utils:api_call(put, "/elements/key", Headers, <<>>),
+  #{status_code := 400} =
+    sr_test_utils:api_call(patch, "/elements/key", Headers, <<>>),
   #{status_code := 400} =
     sr_test_utils:api_call(post, "/elements", Headers, <<"{">>),
   #{status_code := 400} =
     sr_test_utils:api_call(put, "/elements/broken", Headers, <<"{">>),
   #{status_code := 400} =
     sr_test_utils:api_call(put, "/elements/key", Headers, <<"{">>),
+  #{status_code := 400} =
+    sr_test_utils:api_call(patch, "/elements/key", Headers, <<"{">>),
 
   ct:comment("Missing parameters are reported"),
   None = #{},
@@ -196,6 +218,8 @@ invalid_parameters(_Config) ->
     sr_test_utils:api_call(put, "/elements/none", Headers, None),
   #{status_code := 400} =
     sr_test_utils:api_call(put, "/elements/key", Headers, None),
+  #{status_code := 400} =
+    sr_test_utils:api_call(patch, "/elements/key", Headers, None),
 
   NoVal = #{key => <<"noval">>},
   #{status_code := 400} =
@@ -204,12 +228,15 @@ invalid_parameters(_Config) ->
     sr_test_utils:api_call(put, "/elements/noval", Headers, NoVal),
   #{status_code := 400} =
     sr_test_utils:api_call(put, "/elements/key", Headers, NoVal),
+  #{status_code := 400} =
+    sr_test_utils:api_call(patch, "/elements/key", Headers, NoVal),
 
   {comment, ""}.
 
 -spec not_found(sr_test_utils:config()) -> {comment, string()}.
 not_found(_Config) ->
   ct:comment("Not existing element is not found"),
   #{status_code := 404} = sr_test_utils:api_call(get, "/elements/notfound"),
+  #{status_code := 404} = sr_test_utils:api_call(patch, "/elements/notfound"),
   #{status_code := 404} = sr_test_utils:api_call(delete, "/elements/notfound"),
   {comment, ""}.

test/sr_test/sr_elements.erl

@@ -87,11 +87,14 @@ from_json(Json) ->
 -spec update(element(), sumo_rest_doc:json()) ->
   {ok, element()} | {error, iodata()}.
 update(Element, Json) ->
-  case from_json(Json) of
-    {error, Reason} -> {error, Reason};
-    {ok, Updates} ->
-      UpdatedElement = maps:merge(Element, Updates),
-      {ok, UpdatedElement#{updated_at => calendar:universal_time()}}
+  try
+    NewValue = maps:get(<<"value">>, Json),
+    UpdatedElement =
+      Element#{value := NewValue, updated_at := calendar:universal_time()},
+    {ok, UpdatedElement}
+  catch
+    _:{badkey, Key} ->
+      {error, <<"missing field: ", Key/binary>>}
   end.
 
 -spec uri_path(element()) -> binary().

test/sr_test/sr_single_element_handler.erl

@@ -13,6 +13,7 @@
           , content_types_provided/2
           , handle_get/2
           , handle_put/2
+          , handle_patch/2
           , delete_resource/2
           ]
         }]).
@@ -42,6 +43,13 @@ trails() ->
         , produces => ["application/json"]
         , parameters => [Id]
         }
+     , patch =>
+       #{ tags => ["elements"]
+        , description => "Updates an element"
+        , consumes => ["application/json"]
+        , produces => ["application/json"]
+        , parameters => [RequestBody, Id]
+        }
      , put =>
        #{ tags => ["elements"]
         , description => "Updates or creates a new element"