add @SuccessCode UDA to return other 2XX codes

tests/rest/source/app.d

@@ -449,6 +449,25 @@ class Example7 : Example7API {
 	}
 }
 
+@rootPathFromName
+@safe interface Example8API {
+	// POST /entry1/
+	// returns 201 Created
+	@successCode(HTTPStatus.created)
+	void createEntry1();
+	// POST /entry2/
+	void createEntry2();
+	// POST /entry3/
+	@successCode(HTTPStatus.created)
+	int createEntry3();
+}
+
+class Example8 : Example8API {
+	void createEntry1() {}
+	@successCode(HTTPStatus.created)
+	void createEntry2() {}
+	int createEntry3() { return 0; }
+}
 
 void runTests()
 {
@@ -589,6 +608,21 @@ void runTests()
 			assert(answer == expected);
 		}
 	}
+
+	// Example 8
+	{
+		import vibe.http.client : requestHTTP;
+
+		foreach (path; ["entry1", "entry2", "entry3"]) {
+			auto res = requestHTTP("http://127.0.0.1:8080/example8_api/" ~ path,
+		    	                   (scope r) {
+				r.method = HTTPMethod.POST;
+			});
+
+			assert(res.statusCode == HTTPStatus.created);
+			res.dropBody;
+		}
+	}
 }
 
 shared static this()
@@ -604,6 +638,7 @@ shared static this()
 	registerRestInterface(routes, new Example5());
 	registerRestInterface(routes, new Example6());
 	registerRestInterface(routes, new Example7());
+	registerRestInterface(routes, new Example8());
 
 	auto settings = new HTTPServerSettings();
 	settings.port = 8080;

tests/vibe.web.web/source/app.d

@@ -36,11 +36,20 @@ shared static this()
 		}
 		test("/foo", HTTPStatus.notFound);
 		test("/bar", HTTPStatus.ok);
+		test("/status1", HTTPStatus.created);
+		test("/status2", HTTPStatus.noContent);
+		test("/status3", HTTPStatus.internalServerError);
 		logInfo("All web tests succeeded.");
 	});
 }
 
 class Service {
 	@noRoute void getFoo(HTTPServerResponse res) { res.writeBody("oops"); }
 	void getBar(HTTPServerResponse res) { res.writeBody("ok"); }
+	@successCode(HTTPStatus.created)
+	void getStatus1(HTTPServerResponse res) { res.writeVoidBody(); }
+	@successCode(HTTPStatus.created)
+	void getStatus2(HTTPServerResponse res) { status = HTTPStatus.noContent; res.writeVoidBody(); }
+	@successCode(HTTPStatus.created)
+	void getStatus3(HTTPServerResponse res) { throw new Exception(""); }
 }

web/vibe/web/common.d

@@ -297,6 +297,39 @@ ContentTypeAttribute contentType(string data)
 }
 
 
+/**
+	Attribute to set the 2XX HTTP status code returned when the method succeeds.
+ */
+SuccessCodeAttribute successCode(HTTPStatus code)
+@safe {
+	if (!__ctfe)
+		assert(false, onlyAsUda!__FUNCTION__);
+	assert(isSuccessCode(code));
+	return SuccessCodeAttribute(code);
+}
+
+///
+unittest {
+	interface IAPI
+	{
+		// Will return "201 Created" instead of default "200 OK"
+		@successCode(HTTPStatus.created) void createEntry();
+	}
+}
+
+/// Get any applied successCode value or return `default_`
+HTTPStatus extractSuccessCode(alias Func)(HTTPStatus default_ = HTTPStatus.ok)
+{
+	import std.meta : Filter;
+	import vibe.internal.meta.traits : RecursiveFunctionAttributes;
+	enum pred(alias E) = is(typeof(E) == SuccessCodeAttribute);
+	alias UDAs = Filter!(pred, RecursiveFunctionAttributes!(Func));
+	static if (UDAs.length)
+		return UDAs[0];
+	else
+		return default_;
+}
+
 /**
 	Attribute to force a specific HTTP method for an interface method.
 
@@ -472,6 +505,13 @@ package struct MethodAttribute
 	alias data this;
 }
 
+/// private
+package struct SuccessCodeAttribute
+{
+	HTTPStatus data;
+	alias data this;
+}
+
 /// private
 package struct PathAttribute
 {

web/vibe/web/rest.d

@@ -1398,15 +1398,17 @@ private HTTPServerRequestDelegate jsonMethodHandler(alias Func, size_t ridx, T)(
 			static if (is(RT == void)) {
 				() @trusted { __traits(getMember, inst, Method)(params); } (); // TODO: remove after deprecation period
 				returnHeaders();
+				res.statusCode = extractSuccessCode!CFunc(cast(HTTPStatus) res.statusCode);
 				res.writeBody(cast(ubyte[])null);
 			} else {
 				auto ret = () @trusted { return __traits(getMember, inst, Method)(params); } (); // TODO: remove after deprecation period
 
-				static if (!__traits(compiles, () @safe { evaluateOutputModifiers!Func(ret, req, res); } ()))
+				static if (!__traits(compiles, () @safe { evaluateOutputModifiers!CFunc(ret, req, res); } ()))
 					pragma(msg, "Non-@safe @after evaluators are deprecated - annotate @after evaluator function for "~T.stringof~"."~Method~" as @safe.");
 
 				ret = () @trusted { return evaluateOutputModifiers!CFunc(ret, req, res); } ();
 				returnHeaders();
+				res.statusCode = extractSuccessCode!CFunc(cast(HTTPStatus) res.statusCode);
 				debug res.writePrettyJsonBody(ret);
 				else res.writeJsonBody(ret);
 			}

web/vibe/web/web.d

@@ -992,6 +992,9 @@ private void handleRequest(string M, alias overload, C, ERROR...)(HTTPServerRequ
 	static if (hasAuth)
 		handleAuthorization!(C, overload, params)(auth_info);
 
+	// set statusCode before calling method so it can be altered
+	res.statusCode = extractSuccessCode!overload(cast(HTTPStatus) res.statusCode);
+
 	// execute the method and write the result
 	try {
 		import vibe.internal.meta.funcattr;