import java.net.*;
import java.io.*;
import java.util.*;

public class HTTPServer {
String NAME;
String VERSION;
int serverPort;

//Iniciamos el servidor por el puerto 8000.
public static void main(String args[]){
  HTTPServer server = new HTTPServer("HTTPServer", "1.0", 8000);
  server.run();
}

public HTTPServer(String name, String version, int port) {
  this.NAME = name;
  this.VERSION = version;
  this.serverPort = port;
}

public void displayVersionInfo(){
  System.out.println(NAME+" version "+VERSION);
}

//Arrancamos el servicio...
public void run() {
  displayVersionInfo();
  try { //Leemos del socket...
   ServerSocket server = getServerSocket();
   int localPort = server.getLocalPort();
   System.out.println(NAME+" is listening on port "+localPort+".");
   do {
    Socket client = server.accept();
    (new HTTPServerThread(client)).start();
   } while(true);
  } catch(Exception ex) {
   System.out.println("Unable to listen on "+serverPort+".");
   ex.printStackTrace();
   System.exit(1);
  }
}

ServerSocket getServerSocket() throws Exception {
  return new ServerSocket(serverPort);
}
}

//Clase encargada de atender las solicitudes del cliente...
class HTTPServerThread extends Thread {
Socket client;

public HTTPServerThread(Socket client) {
  this.client = client;
}

public void run() {
  try {
   describeConnection(client);
   BufferedOutputStream outStream = new
   BufferedOutputStream(client.getOutputStream());
   HTTPInputStream inStream = new HTTPInputStream(client.getInputStream());
   HTTPRequest request = inStream.getRequest();
   request.log();
   if(request.isGetRequest())
    processGetRequest(request,outStream, inStream);
   System.out.println("Request completed. Closing connection.");
  }catch(IOException ex) {
   System.out.println("IOException occurred when processing request.");
  }
  try {
   client.close();
  }catch(IOException ex) {
   System.out.println("IOException occurred when closing socket.");
  }
}

void describeConnection(Socket client) {
  String destName = client.getInetAddress().getHostName();
  String destAddr = client.getInetAddress().getHostAddress();
  int destPort = client.getPort();
  System.out.println("Accepted connection to "+destName+" ("
   +destAddr+")"+" on port "+destPort+".");
}

void processGetRequest(HTTPRequest request,BufferedOutputStream outStream, HTTPInputStream inStream)
   throws IOException {

  String fileName = request.getFileName();
  File file = new File(fileName);

  if(file.exists()) sendFile(request, outStream, inStream,file);
  else System.out.println("File "+file.getCanonicalPath()+" does not exist.");
}

//Envia el fichero al usuario...
void sendFile(HTTPRequest req, BufferedOutputStream out, HTTPInputStream inStream,File file) {
  try {
   DataInputStream in = new DataInputStream(new FileInputStream(file));
   int len = (int) file.length();
   byte buffer[] = new byte[len];
   in.readFully(buffer);
   in.close();

        //Compruebo si es un cliente autentificado...
        if (req.isUser()) {
           out.write("HTTP/1.0 200 OK\r\n".getBytes());
           out.write(("Content-Length: " + buffer.length + "\r\n").getBytes());
           out.write("Content-Type: text/html\r\n\r\n".getBytes());
           out.write(buffer);
        } else { //Pido que se autentifique...
           out.write("HTTP/1.1 401 Unauthorized\r\n".getBytes());
           out.write("WWW-Authenticate: Basic realm= WallyWorld\r\n\r\n".getBytes());
        }

   out.flush();
   out.close();
  }catch(Exception ex){
   try {
    out.write(("HTTP/1.0 400 " + "No can do" + "\r\n").getBytes());
    out.write("Content-Type: text/html\r\n\r\n".getBytes());
   }catch(IOException ioe) {
   }
   System.out.println("Error retrieving "+file);
  }
}
}

class HTTPInputStream extends FilterInputStream {

public HTTPInputStream(InputStream in) {
  super(in);
}

public String readLine() throws IOException {
  StringBuffer result=new StringBuffer();
  boolean finished = false;
  boolean cr = false;
  do {
   int ch = -1;
   ch = read();
   if(ch==-1) return result.toString();
   result.append((char) ch);
   if(cr && ch==10){
    result.setLength(result.length()-2);
    return result.toString();
   }
   if(ch==13) cr = true;
   else cr=false;
  } while (!finished);
  return result.toString();
}

public HTTPRequest getRequest() throws IOException {
  HTTPRequest request = new HTTPRequest();
  String line;
  do {
   line = readLine();
   if(line.length()>0) request.addLine(line);
   else break;
  }while(true);
  return request;
}
}

class HTTPRequest {
Vector lines = new Vector();

public HTTPRequest() {
}

public void addLine(String line) {
  lines.addElement(line);
}

boolean isGetRequest() {
  if(lines.size() > 0) {
   String firstLine = (String) lines.elementAt(0);
   if(firstLine.length() > 0)
    if(firstLine.substring(0,3).equalsIgnoreCase("GET"))
     return true;
  }
  return false;
}

String getFileName() {
  if(lines.size()>0) {
   String firstLine = (String) lines.elementAt(0);
   String fileName = firstLine.substring(firstLine.indexOf(" ")+1);
   int n = fileName.indexOf(" ");
   if(n!=-1) fileName = fileName.substring(0,n);
   try {
    if(fileName.charAt(0) == '/') fileName = fileName.substring(1);
   } catch(StringIndexOutOfBoundsException ex) {}
   if(fileName.equals("")) fileName = "index.htm";
   if(fileName.charAt(fileName.length()-1)=='/')
    fileName+="index.htm";
   return fileName;
  }else return "";
}

void log() {
  System.out.println("Received the following request:");
  for(int i=0;i<lines.size();++i)
   System.out.println((String) lines.elementAt(i));
}

//Declaramos el usuario y password del cliente...
static final String USER = "pxc";
static final String PSW = "abc";

//Funcion que determina si el usuario y password son correctos...
boolean isUser() {
   System.out.println("Respuesta cliente:");
   for(int i = 0; i < lines.size(); i++)
   {
           System.out.println((String)lines.elementAt(i));

        String line = (String) lines.elementAt(i);
        String str[] = line.split(" ");
        if (str[0].equals("Authorization:")) {
                String id = Base64.decodeToString(str[2]);
                String userpw[] = id.split(":");
                if (userpw[0].equals(USER) && userpw[1].equals(PSW))
                        return true;
                else
                        return false;
        }

  }
  return false;
}
}