Untitled

package lab_redes;

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

    class HttpRequest implements Runnable {

 // Constants
 // Recognized HTTP methods
        final static class HTTP_METHOD
 {
        final static String GET = "GET";
        final static String HEAD = "HEAD";
        final static String POST = "POST";
 }

        final static String HTTPVERSION = "HTTP/1.0";
        final static String CRLF = "\r\n";
        Socket socket;

    // Constructor
    public HttpRequest(Socket socket) throws Exception
       {
            this.socket = socket;
       }

                public HttpRequest() {
        }
    // Implement the run() method of the Runnable interface.
    @Override
    public void run() {
        try {
		processRequest();
	} catch (Exception e) {
		System.out.println(e);
	}

    }
    private void processRequest() throws Exception
	{

DataOutputStream os = new DataOutputStream(socket.getOutputStream());
/* InputStream = An InputStreamReader is a bridge from byte streams to character streams: It reads
bytes and decodes them into characters using a specified charset. The charset
that it uses may be specified by name or may be given explicitly, or
the platform's default charset may be accepted.*/

/*
BufferedReader = Reads text from a character-input stream, buffering characters so as
to provide for the efficient reading of characters, arrays, and lines.
                                */
/*
A data output stream lets an application write primitive Java data types to an
output stream in a portable way. An application can then use a data
input stream to read the data back in.
            */

 // Get the input and output streams of the socket.
            InputStream ins = socket.getInputStream();
            DataOutputStream outs = new DataOutputStream(socket.getOutputStream());

 // Set up input stream filters
            BufferedReader br = new BufferedReader(new InputStreamReader(ins));

// Get the request line of the HTTP request
            String requestLine = br.readLine();

 // Display the request line
            System.out.println();
            System.out.println("Request:");
            System.out.println(" " + requestLine);
// Get and display the header lines.
            String headerLine = null;
            while ((headerLine = br.readLine()).length() != 0) {
            System.out.println(headerLine);
                                                               }

// Extract the filename from the request line.
StringTokenizer tokens = new StringTokenizer(requestLine);
tokens.nextToken();  // skip over the method, which should be "GET"
String fileName = tokens.nextToken();

// Prepend a "." so that file request is within the current directory.
fileName = "." + fileName;


//we will use a try/catch construction to set the boolean variable fileExists to false. Later in the code, we
//will use this flag to construct an error response message, rather than try to send a nonexistent file.
// Open the requested file.
FileInputStream fis = null;
boolean fileExists = true;
try {
	fis = new FileInputStream(fileName);
} catch (FileNotFoundException e) {
	fileExists = false;
}

// Construct the response message.
// Debug info for private use
	System.out.println("Partiu");
	System.out.println(requestLine);
	while ((headerLine = br.readLine()).length() != 0) {
	    System.out.println(headerLine);
	}

	// Construct the response message.
        String statusLine = null;
        String contentTypeLine = null;
        String entityBody = null;
        if (fileExists) {
	    statusLine = "HTTP/1.0 200 OK" + CRLF;
	    contentTypeLine = "Content-Type: " +
		contentType(fileName) + CRLF;
        } else {
	    statusLine = "HTTP/1.0 404 Not Found" + CRLF;
	    contentTypeLine = "Content-Type: text/html" + CRLF;
	    entityBody = "<HTML>" +
		"<HEAD><TITLE>Not Found</TITLE></HEAD>" +
		"<BODY>Not Found</BODY></HTML>";
        }
	// Send the status line.
        os.writeBytes(statusLine);

        // Send the content type line.
        os.writeBytes(contentTypeLine);

        // Send a blank line to indicate the end of the header lines.
        os.writeBytes(CRLF);

        // Send the entity body.
        if (fileExists) {
	    sendBytes(fis, os);
	    fis.close();
        } else {
	    os.writeBytes(entityBody) ;
        }

        // Close streams and socket.
        os.close();
        br.close();
        socket.close();

    }

    private static void sendBytes(FileInputStream fis,
				  OutputStream os) throws Exception {
	// Construct a 1K buffer to hold bytes on their way to the socket.
	byte[] buffer = new byte[1024];
	int bytes = 0;

	// Copy requested file into the socket's output stream.
	while ((bytes = fis.read(buffer)) != -1) {
	    os.write(buffer, 0, bytes);
	}
    }

    private static String contentType(String fileName) {
	if(fileName.endsWith(".htm") || fileName.endsWith(".html")) {
	    return "text/html";
	}
	if(fileName.endsWith(".ram") || fileName.endsWith(".ra")) {
	    return "audio/x-pn-realaudio";
	}
	return "application/octet-stream" ;
    }

}