problema comunicazione tra php e arduino tramite get request con curl

buona sera, sto cercando di far comunicare un server con uno script php con arduino inviando una richiesta http get utilizzando le curl da php e arduino dovrebbe leggera ed eseguire un comando e non riuscendoci siccome non so come fare il parsing della richiesta l’ ho modificato così in modo che anche se non fa il parsing dovrebbe comunque inviare una risposta ma non succede ne via ethernet ne dalla porta seriale.

#include <SPI.h>
#include <Ethernet.h>

// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {
  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
};
IPAddress ip(192, 168, 1, 177);

// Initialize the Ethernet server library
// with the IP address and port you want to use
// (port 80 is default for HTTP):
EthernetServer server(80);

void setup() {
  // Open serial communications and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }


  // start the Ethernet connection and the server:
  Ethernet.begin(mac, ip);
  server.begin();
  Serial.print("server is at ");
  Serial.println(Ethernet.localIP());
}


void loop() {
  // listen for incoming clients
  EthernetClient client = server.available();
  if (client) {
    Serial.println("new client");
    // an http request ends with a blank line
    boolean currentLineIsBlank = true;
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();
        Serial.write(c);
        // if you've gotten to the end of the line (received a newline
        // character) and the line is blank, the http request has ended,
        // so you can send a reply
        if (c == '\n' && currentLineIsBlank) {
          // send a standard http response header
          Serial.println(c); // debug
          client.println("HTTP/1.1 200 OK");
          client.println("Content-Type: text/html");
          client.println("Connection: close");  // the connection will be closed after completion of the response
          client.println("Refresh: 5");  // refresh the page automatically every 5 sec
          client.println();
          client.println("<!DOCTYPE HTML>");
          client.println("<html><body>prova<//body>");
          client.println("</html>");
          break;
        }
        if (c == '\n') {
          // you're starting a new line
          currentLineIsBlank = true;
        }
        else if (c != '\r') {
          // you've gotten a character on the current line
          currentLineIsBlank = false;
        }
      }
    }
    // give the web browser time to receive the data
    delay(1);
    // close the connection:
    client.stop();
    Serial.println("client disconnected");
  }
}

e invio i dati con questo codice php:

<?php
$curl = curl_init();
$arraydati = array(CURLOPT_RETURNTRANSFER => 1, CURLOPT_URL => "http://192.168.1.177:80/?comando=on", CURLOPT_USERAGENT => "useragent");
curl_setopt_array($curl, $arraydati);
$risposta = curl_exec($curl);
print $risposta;
?>

potete aiutarmi a capire come farli comunicare tra loro e a fare il parsing delle richieste get?

salve, ho provato a modificare il codice così:

#include <SPI.h>
#include <Ethernet.h>

byte mac[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};

IPAddress ip(192, 168, 0, 177);

EthernetServer server(90);

void setup()
{
Serial.begin(9600);
Ethernet.begin(mac, ip);
server.begin();
Serial.print("server is at ");
Serial.println(Ethernet.localIP());
}


void loop()
{
	EthernetClient client = server.available();
	if (client)
	{
	Serial.println("new client");
	boolean currentLineIsBlank = true;
	while (client.connected())
	{
		if (client.available())
		{
			char c = client.read();
			String result = result + String(c);
			String prova = '?var=value';
		}

			if (result.equals(prova))
			{
				client.println("HTTP/1.1 200 OK");
				client.println("Content-Type: text/html");
				client.println("Connection: close");// the connection will be closed after completion of the response
				client.println("Refresh: 5");// refresh the page automatically every 5 sec
				client.println();
				client.println("<!DOCTYPE HTML>");
				client.println("<html><body>prova<//body>");
				client.println("</html>");
				break;
			}

		}

	}
	delay(1);
	client.stop();
	Serial.println("client disconnected");
}

ma quando compilo mi da errore:

C:/Users/Utente/Documents/Arduino/asd/asd.ino: In function 'void loop()':

C:/Users/Utente/Documents/Arduino/asd/asd.ino:33: error: conversion from 'int' to 'String' is ambiguous

c:/program files (x86)/arduino/hardware/arduino/cores/arduino/WString.h:61: note: candidates are: String::String(const __FlashStringHelper*) <near match>

c:/program files (x86)/arduino/hardware/arduino/cores/arduino/WString.h:59: note:                 String::String(const char*) <near match>

C:/Users/Utente/Documents/Arduino/asd/asd.ino:36: error: 'result' was not declared in this scope

C:/Users/Utente/Documents/Arduino/asd/asd.ino:36: error: 'prova' was not declared in this scope