some optimization

src/users/add_user.cpp

@@ -62,7 +62,7 @@ void add_user(const httplib::Request& request, httplib::Response& response)
         return;
     }
 
-    std::ifstream usersfile("users.json");
+    std::ifstream usersfile(USERS_FILE);
     nlohmann::json all_users = nlohmann::json::parse(usersfile);
     usersfile.close();
 
@@ -104,11 +104,10 @@ void add_user(const httplib::Request& request, httplib::Response& response)
     new_user_data << "}";
     all_users.push_back(nlohmann::json::parse(new_user_data));
 
-    std::ofstream usersfilew("users.json");
+    std::ofstream usersfilew(USERS_FILE);
     usersfilew << all_users.dump(4);
     usersfilew.close();
-    std::stringstream syslogstring;
-    syslogstring << "user added [" << username << "]";
-    syslog(LOG_INFO, syslogstring.str().c_str());
+    std::string syslogstring = "user added [" + username + "]";
+    syslog(LOG_INFO, syslogstring.c_str());
     response.set_content(R"({"status":"ok"})", JSON_TYPE);
 }