Session drops while receiving response from POST request

Projects Programming
1

Hi,

I am trying to carry out a XML-RPC-like call from my Arduino Mega to a local server listening on port 8169.

The response I print on the Serial Monitor reads "HT" (first two letters of the "HTTP/1.1..." response) before connection breaks. When I use my code to call port 80, I receive a proper 404 response. When I do the PUT request to port 8169 from my computer using POSTMAN, I receive "200 OK". Any idea what the problem might be?

Here is my test code:

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


byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress server(192,168,1,2); 
IPAddress ip(192, 168, 1, 119);

EthernetClient client;

String PostData = "<methodCall><methodName></methodName><params><param></param></params></methodCall>"; // payload goes here

void setup() {

  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect.
  }

  Ethernet.begin(mac, ip);
  
  delay(1000);
  Serial.println("connecting...");

  if (client.connect(server, 8169)) {
    Serial.println("connected");

    client.println("POST /xmlrpc/common HTTP/1.1");
    client.println("Host: 192.168.1.2:8169");
    client.println("User-Agent: Arduino/1.0");
    client.println("Connection: close");
    client.print("Content-Length: ");
    client.println(PostData.length());
    client.println();
    client.println(PostData);
    client.println();
  } else {
    Serial.println("connection failed");
  }
}

void loop() {
  if (client.available()) {
    char c = client.read();
    Serial.print(c);
  }

  if (!client.connected()) {
    Serial.println();
    Serial.println("disconnecting.");
    client.stop();

    while (true);
  }
}

And here the monitor response again:

connecting...
connected
HT
disconnecting.

Thanks for your help!

2

that is odd as client connected() should evaluate to true whilst there is unread data. so perhaps it is timing out somehow. try debugging by inserting a delay after sending the data and perhaps another 50-100 ms within a while loop to go inside the if conditional.

if (client.available()) {
    while(client.available()){
     char c = client.read();
     Serial.print(c);
     delay(50);
    }
}
3

You should have two while loops

   while(client.connected())
   {
      while(client.available() > 0)
      {
         // read the data
      }
   }
4

@jpadie:

     char c = client.read();
     Serial.print(c);
     delay(50);

WTF is that delay() in there for?

5

Great! That made it work. Thanks a lot! :slight_smile: