Fix: send request / receive json data

src/web/js/main.js

@@ -33,5 +33,4 @@ function logout() {
 	maestroID = -1;
 	sessionStorage.setItem("maestroID", maestroID);
 	location.href = './../main/index.html';
-}
-
+}

src/web/js/request_server.js

@@ -0,0 +1,63 @@
+function sendRequestServer(url, sendParams, onSuccess, onFail, isDebugMode) {
+	// console.log(url);
+	// console.log(sendParams);
+	// console.log(onSuccess);
+	// console.log(onFail);
+	// console.log(isDebugMode);
+
+	let xhr = new XMLHttpRequest(); //new로 생성.
+	xhr.open('POST', url, true);
+	xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
+	xhr.send(sendParams);
+	xhr.onload = function() {
+		if(xhr.readyState === 4 && xhr.status === 200) {
+			// console.log(xhr.responseText);
+			// console.log(xhr.responseText.length);
+
+			if(xhr.responseText.length === 0 || xhr.responseText === null) {
+				let error_message = "서버에서 요청을 수행하지 못했습니다.";
+				printErrorMessage(error_message, onFail, isDebugMode);
+				return;
+			}
+
+			let jsonReply = JSON.parse(xhr.responseText);
+			// console.log(jsonReply);
+
+			if(jsonReply === null) {
+				let error_message = "서버에서 데이터가 넘어오지 않았습니다.";
+				printErrorMessage(error_message, onFail, isDebugMode);
+				return;
+			}
+
+			if(!isSuccess(jsonReply)) {
+				let error_message = getErrorMessage(jsonReply);
+				printErrorMessage(error_message, onFail, isDebugMode);
+				return;
+			}
+
+			onSuccess(jsonReply);
+		}
+	}
+}
+
+function isSuccess(jsonReply) {
+	if(jsonReply["result"] === undefined)
+		return false;
+
+	if(jsonReply["result"] === "fail")
+		return false;
+
+	return true;
+}
+
+function getErrorMessage(jsonReply) {
+	return jsonReply["error"];
+}
+
+function printErrorMessage(message, onFail, isDebugMode) {
+	if(onFail !== undefined && onFail !== null)
+		onFail(message);
+
+	if(isDebugMode === true)
+		console.log(message);
+}