message: style: subtle changes to ghttp;
  by zengli
diff: //operation.log: not used
  //query.log: query string, result num, and time of answering
  +//TODO: extract server.get into new functions
  +
  #include "../Server/server_http.hpp"
  #include "../Server/client_http.hpp"
  //db
  @@ -178,6 +180,7 @@ int initialize(int argc, char *argv[])
  }
  }
  cout << "server port: " << server.config.port << " database name: " << db_name << endl;
  + //USAGE: then user can use http://localhost:port/ to visit the server or coding with RESTful API
  Util util;
  //HTTP-server at port 9000 using 1 thread
  @@ -581,7 +584,10 @@ int initialize(int argc, char *argv[])
  + //NOTICE:this may not be visited by browser directly if the browser does not do URL encode automatically!
  + //In programming language, do URL encode first and then call server, then all is ok
  server.resource["^/%3Foperation%3[D|d]monitor$"]["GET"]=[&server](shared_ptr<HttpServer::Response> response, shared_ptr<HttpServer::Request> request) {
  + //server.resource["^/monitor$"]["GET"]=[&server](shared_ptr<HttpServer::Response> response, shared_ptr<HttpServer::Request> request) {
  cout<<"HTTP: this is monitor"<<endl;
  if(current_database == NULL)
  {
  