indexOf help

I have an UNO with and ethernet shield and i'm using it as a web server. I'm trying to determine if the requested URL contains the words "warm" or "cool". I'm appending the results of to a string and then trying to use indexOf() on it. Here's part of my code. I'm putting the word "warm" into my url but it never turns the 'mode' variable to "warm". I'm thinking maybe indexOf is being thrown off because it might contain '\n' or '\r' but that's a complete guess. Anybody know what's going on here?

      while (client.connected()) {
        if (client.available()) {
          char c =;
          //cast c to a string so we can append it 
          Cc = String(c);
          requestString += Cc;

         if (c == '\n' && currentLineIsBlank) {
            //try to get mode('cool' or 'warm') from request string
            if(requestString.indexOf("warm") >=0){
              mode = "Warm"; 
            if(requestString.indexOf("cool") >=0){
              mode = "Cool"; 

The advice is, don't use the string class on arduino, because it has bugs in it.

The first thing to do, would be to send your string back to the serial monitor on the pc,
to see if it actually has in it, what you think is in it.

Simple indexof code.

//zoomkat 4-1-12
//simple button GET for servo and pin 5
//for use with IDE 1.0
//open serial monitor to see what the arduino receives
//use the \ slash to escape the " in the html, or use ' instead of " 
//address will look like when submited
//for use with W5100 based ethernet shields

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

#include <Servo.h> 
Servo myservo;  // create servo object to control a servo 

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; //physical mac address
byte ip[] = { 192, 168, 1, 102 }; // ip in lan
byte gateway[] = { 192, 168, 1, 1 }; // internet access via router
byte subnet[] = { 255, 255, 255, 0 }; //subnet mask
EthernetServer server(84); //server port

String readString; 


void setup(){

  pinMode(5, OUTPUT); //pin selected to control
  //start Ethernet
  Ethernet.begin(mac, ip, gateway, gateway, subnet);

  myservo.write(90); //set initial servo position if desired
  myservo.attach(7);  //the pin for the servo control
  //enable serial data print 
  Serial.println("server servo/pin 5 test 1.0"); // so I can keep track of what is loaded

void loop(){
  // Create a client connection
  EthernetClient client = server.available();
  if (client) {
    while (client.connected()) {
      if (client.available()) {
        char c =;

        //read char by char HTTP request
        if (readString.length() < 100) {

          //store characters to string 
          readString += c; 

        //if HTTP request has ended
        if (c == '\n') {

          Serial.println(readString); //print to serial monitor for debuging 

          client.println("HTTP/1.1 200 OK"); //send new page
          client.println("Content-Type: text/html");

          client.println("<TITLE>Arduino GET test page</TITLE>");

          client.println("<H1>Zoomkat's simple Arduino button</H1>");
          client.println("<a href=\"/?on\">ON</a>"); 
          client.println("<a href=\"/?off\">OFF</a>"); 

          //stopping client

          ///////////////////// control arduino pin
          if(readString.indexOf("on") >0)//checks for on
            digitalWrite(5, HIGH);    // set pin 5 high
            Serial.println("Led On");
          if(readString.indexOf("off") >0)//checks for off
            digitalWrite(5, LOW);    // set pin 5 low
            Serial.println("Led Off");
          //clearing string for next read