byte NUL = 0x00;
byte START_HEADER = 0x01;
byte START_TEXT = 0x02;
byte END_TRANSMISSION = 0x04;
byte ESC = 0x1B;
byte FILL = 0x30;
byte ROTATE = 0x61;
byte SLOW = 0x15;
byte FAST = 0x19;
byte TIME = 0x13;
byte CALL_STRING = 0x10;
byte CALL_SIZE = 0x1A;
byte SIZE_LARGE = 0x33;
byte SIZE_SMALL = 0x31;

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

char response[32];
long pollingInterval = 3000; // in milliseconds
boolean failed = false;

byte mac[] = {  
  0x00, 0xAA, 0xBB, 0xCC, 0xDE, 0x02 };
IPAddress server(XXX,XXX,XXX,XXX); //your server's IP here


EthernetClient client;


void setup () {
  delay(5000);
  Serial.begin(9600);
  Serial.println("Allocating Memory...");
  allocateMemory();
  Serial.println();
  Serial.println("Setting Text...");
  writeText();
  Serial.println();

  if (Ethernet.begin(mac) == 0) {
    Serial.println("Failed to configure Ethernet using DHCP");
    // no point in carrying on, so do nothing forevermore:
    while(true);


    delay(1000);

  }
}


void loop() {
  if (client.connect(server, 80)) {
    Serial.println("connected");
    // Make a HTTP request:
    client.println("GET /~path/to/reddit.php");
    client.println();
    delay(1000);
  } 
  else {
    // if you didn't get a connection to the server:
    Serial.println("connection failed");
    failed = true;

  }
  if (!failed) {
    delay(1000);
    if (client.available()) {
      int i = 0;
      memset( &response, 0, 32 );
      do {
        response[i] = client.read();
        i++;
        delay(1);
      } 
      while (client.available());
      Serial.print("response length: ");
      Serial.println(i);
      response[i] = '\0';
    }

    Serial.print("Response from server: ");
    Serial.println(response);
    client.stop();

    writeRedditString(response);
  }
  failed = false;

  delay(pollingInterval);


  if (client.connect(server, 80)) {
    Serial.println("connected");
    // Make a HTTP request:
    client.println("GET /~path/to/reddit_change.php");
    client.println();
    delay(1000);
  } 
  else {
    // if you didn't get a connection to the server:
    Serial.println("connection failed");
    failed = true;

  }
  if (!failed) {
    delay(1000);
    if (client.available()) {
      int i = 0;
      memset( &response, 0, 32 );
      do {
        response[i] = client.read();
        i++;
        delay(1);
      } 
      while (client.available());
      Serial.print("response length: ");
      Serial.println(i);
      response[i] = '\0';
    }

    Serial.print("Response from server: ");
    Serial.println(response);
    client.stop();

    writeRedditChangeString(response);
  }
  failed = false;
  delay(pollingInterval);
}

void allocateMemory () {
  // See page 41 of manual. 
  Serial.write(NUL); // Start frame sync chars
  Serial.write(NUL);
  Serial.write(NUL);
  Serial.write(NUL);
  Serial.write(NUL); // end frame sync chars
  Serial.write(START_HEADER); // start of header
  Serial.write("Z00"); // all sign types, all addresses
  Serial.write(START_TEXT); //start of text
  Serial.write("E"); // write special functions command
  Serial.write("$AAU0400FF001BL002000002BL00200000");  // allocate memory for text file "A" and two strings, "1" and "2"
  Serial.write(END_TRANSMISSION); // End of transmission
}

void writeText() {
  Serial.write(NUL); // Start frame sync chars
  Serial.write(NUL);
  Serial.write(NUL);
  Serial.write(NUL);
  Serial.write(NUL); // end frame sync chars
  Serial.write(START_HEADER); // start of header
  Serial.write("Z00"); // all sign types, all addresses
  Serial.write(START_TEXT); //start of text
  Serial.write("AA"); // write command, text file A
  Serial.write(ESC);
  Serial.write(FILL);
  Serial.write(ROTATE);
  Serial.write(CALL_SIZE);
  Serial.write(SIZE_LARGE);
  Serial.write("       Reddit: ");
  Serial.write(CALL_STRING);
  Serial.write("1"); // String File
  Serial.write(CALL_SIZE);
  Serial.write(SIZE_SMALL);
  Serial.write(" (");
  Serial.write(CALL_STRING);
  Serial.write("2"); // String Files
  Serial.write(")");
  Serial.write(END_TRANSMISSION); // End of transmission
}


void writeRedditString (String str1) {
  Serial.write(NUL); // Start frame sync chars
  Serial.write(NUL);
  Serial.write(NUL);
  Serial.write(NUL);
  Serial.write(NUL); // end frame sync chars
  Serial.write(START_HEADER); // start of header
  Serial.write("Z00"); // all sign types, all addresses
  Serial.write(START_TEXT); //start of text
  Serial.write("G1"); // write string, string file 1
  Serial.print(str1); // data
  Serial.write(END_TRANSMISSION); // End of transmission 
}

void writeRedditChangeString (String str1) {
  Serial.write(NUL); // Start frame sync chars
  Serial.write(NUL);
  Serial.write(NUL);
  Serial.write(NUL);
  Serial.write(NUL); // end frame sync chars
  Serial.write(START_HEADER); // start of header
  Serial.write("Z00"); // all sign types, all addresses
  Serial.write(START_TEXT); //start of text
  Serial.write("G2"); // write string, string file 2
  Serial.print(str1); // data
  Serial.write(END_TRANSMISSION); // End of transmission 
}