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

public class HTTPServer {
    public static void main(String[] args) throws Exception {

	final int httpd = Integer.parseInt(args[0]); // our port 

	ServerSocket ssock = new ServerSocket(httpd); 

	while (true) {
	    Socket sock = ssock.accept(); 
	    System.out.println("** Client has made socket connection.");
	    OneConnection_C client = new OneConnection_C(sock); 
	    new Thread(client).start(); 
	}
    }
}

class OneConnection {
    Socket sock; 
    BufferedReader in = null; 
    DataOutputStream out = null; 
    OneConnection(Socket sock) throws Exception {
	this.sock = sock;
	in = 
	    new BufferedReader
		(new InputStreamReader
		    (sock.getInputStream())); 
	out = new DataOutputStream(sock.getOutputStream()); 
    }
    String getRequest() throws Exception {
	String s = null; 
	while ((s = in.readLine()) != null) {
	    System.out.println("got: " + s); 
	}
	return s; 
    }
}

class OneConnection_A extends OneConnection {
    OneConnection_A (Socket sock) throws Exception {
	super(sock); 
    }
    String getRequest() throws Exception {
	String s = null; 
	while ((s = in.readLine()) != null) {
	    System.out.println("got: " + s); 
	    if (s.indexOf("GET") > -1) {
		out.writeBytes("HTTP-1.0 200 OK\r\n"); 
		s = s.substring(4); 
		int i = s.indexOf(" "); 
		System.out.println("file: " + s.substring(0, i)); 
		return s.substring(0, i); 
	    }
	}
	return null; 
    }
}

class OneConnection_B extends OneConnection_A {
    OneConnection_B(Socket sock) throws Exception {
	super(sock); 
    }
    void sendFile(String fname) throws Exception {
	String where = "htdocs" + fname; 
	if (where.indexOf("..") > -1) 
	    throw new SecurityException("No access to parent dirs"); 
	System.out.println("Looking for " + where); 
        File f = new File(where); 
	DataInputStream din = new DataInputStream(new FileInputStream(f)); 
	int len = (int) f.length(); 
	byte[] buf = new byte[len]; 
	din.readFully(buf);
	out.writeBytes("Content-Length: " + len + "\r\n"); 
	out.writeBytes("Content-type: text/html\r\n\r\n"); 
	out.write(buf); 
	out.flush();
	out.close(); 
    }
}

class OneConnection_C extends OneConnection_B implements Runnable {
    OneConnection_C(Socket sock) throws Exception {
	super(sock); 
    }
    public void run() {
	try {
	    String filename = getRequest(); 
	    sendFile(filename); 
	} catch (Exception e) {
	    System.out.println("Exception: " + e); 
	}
    }
}