http.server: handle an empty Json body

http/vibe/http/server.d

@@ -985,6 +985,7 @@ final class HTTPServerRequest : HTTPRequest {
 				if (icmp2(contentType, "application/json") == 0 || icmp2(contentType, "application/vnd.api+json") == 0 ) {
 					auto bodyStr = bodyReader.readAllUTF8();
 					if (!bodyStr.empty) _json = parseJson(bodyStr);
+					else _json = Json.undefined;
 				} else {
 					_json = Json.undefined;
 				}

tests/vibe.http.server.empty-json/dub.sdl

@@ -0,0 +1,3 @@
+name "tests"
+description "Receive an empty JSON body"
+dependency "vibe-d:http" path="../../"

tests/vibe.http.server.empty-json/source/app.d

@@ -0,0 +1,34 @@
+import vibe.core.core : runTask, runEventLoop, exitEventLoop;
+import vibe.data.json : serializeToJsonString;
+import vibe.http.client : requestHTTP;
+import vibe.http.server;
+import vibe.stream.operations : readAllUTF8;
+
+import std.conv : to;
+
+void main()
+{
+	auto s1 = new HTTPServerSettings;
+	s1.options &= ~HTTPServerOption.errorStackTraces;
+	s1.bindAddresses = ["127.0.0.1"];
+	s1.port = 11721;
+	listenHTTP(s1, &handler);
+
+	runTask({
+		scope (exit) exitEventLoop();
+		try {
+			auto req = requestHTTP("http://127.0.0.1:" ~ s1.port.to!string);
+			assert(req.bodyReader.readAllUTF8 == "JSON: null - World!\r\n");
+		} catch (Exception e) {
+			assert(false, e.msg);
+		}
+	});
+	runEventLoop();
+}
+
+void handler(scope HTTPServerRequest req, scope HTTPServerResponse res)
+{
+	req.contentType = "application/json; charset=UTF-8";
+	res.bodyWriter.write("JSON: " ~ req.json.serializeToJsonString);
+	res.bodyWriter.write(" - World!\r\n");
+}