(1) param in post
   __ app Client
    #include <Core/Core.h>
    using namespace Upp;
    CONSOLE_APP_MAIN
    {
         HttpRequest http("http://localhost:8001/myapp/qualqueres");
         http.POST().Post("id","1234"); //Via post Data
         Cout() << http.Execute() << EOL;
    }
    __Server
    #include <Skylark/Skylark.h>
    using namespace Upp;
    SKYLARK(q, "qualqueres:POST")
    {
         String c =  http["id"]; //Via post data
         http << c;
    }
    struct MyApp : SkylarkApp {
    	MyApp() {
    		root = "myapp";
		
    	#ifdef _DEBUG
    		prefork = 0;
    		use_caching = false;
    	#endif
    	}
    };

    CONSOLE_APP_MAIN
    {
    #ifdef _DEBUG
    	StdLogSetup(LOG_FILE|LOG_COUT);
    	Ini::skylark_log = true;
    #endif
    	MyApp().Run();	
    }

(2)json 
     __app Client
    CONSOLE_APP_MAIN
    {
         HttpRequest http("http://localhost:8001/myapp/qualqueres");
         http.POST().PostData("{\"id\":\"1234\"}"); //Via post data formated in JSON
         Cout() << http.Execute() << EOL;
    }
    __Server
    SKYLARK(q, "qualqueres:POST")
    {
       String c;
       String dataNotParsed = http.GetRequestContent(); //Via Post data formated in JSON
       Value json = ParseJSON(dataNotParsed);
       if(!IsNull(json["id"]))
    		c = json["id"];
   
       http << c;
    }

(3) header
    __ app Client
    CONSOLE_APP_MAIN
    {
         HttpRequest http("http://localhost:8001/myapp/qualqueres");
     
         http.POST().Header("id","1234"); //Via request header
         Cout() << http.Execute() << EOL;
    }

    __  Server
    SKYLARK(q, "qualqueres:POST")
    {
       String c = http.GetHeader("id"); //Via request header
       http << c;
    }