Add account APIs.

object/check.go

@@ -0,0 +1,23 @@
+package object
+
+func CheckUserRegister(userId string, password string) string {
+	if len(userId) == 0 || len(password) == 0 {
+		return "username and password cannot be blank"
+	} else if HasUser(userId) {
+		return "username already exists"
+	} else {
+		return ""
+	}
+}
+
+func CheckUserLogin(userId string, password string) string {
+	if !HasUser(userId) {
+		return "username does not exist, please sign up first"
+	}
+
+	if !IsPasswordCorrect(userId, password) {
+		return "password incorrect"
+	}
+
+	return ""
+}