import java.io.* ;
import java.net.* ;
import java.util.* ;
public final class WebServer
{
public static void main(String argv[]) throws Exception
{
int port = 6897;
// Establish the listen socket.
ServerSocket listenSocket = new ServerSocket(port);
while (true) {
// Listen for a TCP connection request.
Socket connectionSocket = listenSocket.accept();
// Construct an object to process the HTTP request message
HttpRequest request = new HttpRequest(connectionSocket);
// Create a new thread to process the request.
Thread thread = new Thread(request);
// Start the thread.
thread.start();
}
}
}
final class HttpRequest implements Runnable
{
final static String CRLF = "\r\n";
Socket socket;
// Constructor
public HttpRequest(Socket socket) throws Exception
{
this.socket = socket;
}
// Implement the run() method of the Runnable interface.
public void run()
{
try
{
processRequest();
}
catch (Exception e)
{
System.out.println(e);
}
}
private void processRequest() throws Exception
{
// Get a reference to the socket's input and output streams.
InputStream is = socket.getInputStream();
DataOutputStream os = new DataOutputStream(socket.getOutputStream());
// Set up input stream filters.
BufferedReader br = new BufferedReader(new InputStreamReader(is));
//Get the request line of the HTTP request message.
String requestLine = br.readLine();
//Extract the filename from the request line.
StringTokenizer tokens = new StringTokenizer(requestLine);
boolean badRequest = false;
boolean methodNotImplemented = false;
String fileName = null;
String version = null;
String command = tokens.nextToken();
if (tokens.hasMoreTokens()) {
fileName = tokens.nextToken();
// Prepend a "." so that file request is within the current directory.
fileName = "." + fileName;
}
else {
badRequest = true;
}
if (tokens.hasMoreTokens()) {
version = tokens.nextToken();
}
else {
badRequest = true;
}
if (tokens.hasMoreTokens()) {
badRequest = true;
}
boolean fileExists = true;
boolean fileOpen = true;
FileOutputStream fos = null;
FileInputStream fis = null;
if (!((command.equals("GET")) || (command.equals("HEAD")) || (command.equals("PUT"))))
{
methodNotImplemented = true;
}
if (!version.matches("HTTP/.[.].")) {
System.out.println("Version pattern mismatch");
badRequest = true;
}
// Construct the response message.
String statusLine = null;
String contentTypeLine = null;
String entityBody = null;
if (badRequest) {
statusLine = "HTTP/1.0 400 Bad Request" + CRLF;
contentTypeLine = "Content-type: " + "text/html" + CRLF;
entityBody = "" + "Bad Request"
+ "" + requestLine + " is a bad request" + CRLF;
}
if (methodNotImplemented) {
statusLine = "HTTP/1.0 501 Method Not Implemented" + CRLF;
contentTypeLine = "Content-type: " + "text/html" + CRLF;
entityBody = "" + "Method Not Implemented"
+ " Method " + command + " Not Implemented" + CRLF;
}
if (!(badRequest || methodNotImplemented)) {
if (command.equals("PUT"))
{
try
{
fos = new FileOutputStream(fileName);
}
catch (Exception e)
{
fileOpen = false;
}
}
else
{
// Open the requested file.
try
{
fis = new FileInputStream(fileName);
}
catch (FileNotFoundException e)
{
System.out.println("File not found");
fileExists = false;
}
}
if (fileExists && fileOpen) {
statusLine = "HTTP/1.0 200 OK" + CRLF;
contentTypeLine = "Content-type: " + contentType(fileName) + CRLF;
}
else {
if (!(fileExists)) {
statusLine = "HTTP/1.0 404 Not Found" + CRLF;
contentTypeLine = "Content-type: " + "text/html" + CRLF;
entityBody = "" + "Not Found"
+ "File " + fileName + " Not Found" + CRLF;
}
else
{
statusLine = "HTTP/1.0 404 Not Found" + CRLF;
contentTypeLine = "Content-type: " + "text/html" + CRLF;
entityBody = "" + "Not Found"
+ "File " + fileName + " could not be written" + CRLF;
}
}
}
// 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 (!(badRequest || methodNotImplemented) && (fileExists && fileOpen)) {
if (command.equals("PUT")) {
try
{
int character;
// Read the input data one character at a time until end
// of stream reached
character = br.read();
while (character != -1) {
fos.write(character);
character = br.read();
}
fos.close();
}
catch (Exception e)
{
fos.close();
}
}
else {
if (command.equals("GET")) {
try
{
sendBytes(fis, os);
}
catch (Exception e)
{
System.out.println("Exception raised");
}
}
fis.close();
}
}
else {
System.out.println(entityBody);
os.writeBytes(entityBody);
}
//Display the request line.
System.out.println();
System.out.println(requestLine);
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(".jpg") || fileName.endsWith(".jpeg")) {
return "image/jpeg";
}
if (fileName.endsWith(".gif")) {
return "image/gif";
}
if (fileName.endsWith(".txt")) {
return "text/plain";
}
if (fileName.endsWith(".pdf")) {
return "application/pdf";
}
return "application/octet-stream";
}
}