Simple code to turn LEDs on/off based on web request.

Arduino LED server

#include <Client.h>
#include <Dhcp.h>
#include <dns.h>
#include <Ethernet.h>
#include <Server.h>
#include <sockutil.h>
#include <Udp.h>
#include <util.h>

#include <SPI.h>


#define PINOFFSET 2
#define PINRANGE 5

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

Server server(80);

void setup()
{
   for (int i = 0; i < PINRANGE; i++)
   {
     pinMode(i + PINOFFSET, OUTPUT);
    digitalWrite(i + PINOFFSET, 0);
   }
   
   for (int i = 0; i < PINRANGE; i++)
   {
     digitalWrite(i + PINOFFSET, 1);
     delay(100);
   }
   delay(1000);
   
   for (int i = 0; i < PINRANGE; i++)
   {
     digitalWrite(i+ PINOFFSET, 0);
   }
  
  Serial.begin(9600);
  // Get an IP address to use and also find out our DNS server address
  while (Dhcp.beginWithDHCP(mac) != 1)
  {
    Serial.println("Error getting IP address via DHCP, trying again...");
    delay(15000);
  }    
  delay(1000);
  
  uint8_t localIP[4];
  Dhcp.getLocalIp(localIP);

  Serial.print((int)localIP[0]);
  Serial.print(".");
  Serial.print((int)localIP[1]);
  Serial.print(".");
  Serial.print((int)localIP[2]);
  Serial.print(".");
  Serial.println((int)localIP[3]);
}



void loop()
{
    Client client = server.available();
    if (client) 
    {
       boolean currentLineIsBlank = true;
       char lineBuffer[255];
       int index = 0;
       for (int i = 0; i < 255; i++)
         lineBuffer[i] = 0;
      
      while (client.connected()) 
      {
        if (client.available()) 
        {
          char c = client.read();
          lineBuffer[index++] = 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
          client.println("HTTP/1.1 200 OK");
          client.println("Content-Type: text/html");
          client.println();
          client.println("OK");

          break;
        }
        if (c == '\n') {
          // you're starting a new line
          currentLineIsBlank = true;
          String buffer = String(lineBuffer);
          if (buffer.startsWith("GET"))
          {
            char led, state;
            
            led = lineBuffer[5] - '0';
            state = lineBuffer[6] - '0';
            
            Serial.println((int)led);
            Serial.println((int)state);
          
            Serial.println(lineBuffer);
            
            digitalWrite(led + PINOFFSET, state);
          }
          index = 0;
       for (int i = 0; i < 255; i++)
         lineBuffer[i] = 0;
          
        } 
        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();
  }
}