proxyserver.java

一个基于PlaceLab的室内和室外的智能导航系统

package org.placelab.proxy;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;

import org.placelab.util.StringUtil;

public class ProxyServer extends SocketServer {
	
	public static final int DEFAULT_PORT = 2080;
	
	private Vector servlets = new Vector();
	
	public ProxyServer (int port) {
		super(port, 10, "Placelab Proxy Server");
	}

	public void addServlet (Servlet servlet) {
		if (!servlets.contains(servlet))
			servlets.add(servlet);
	}
	
	private String readLine (InputStream in)
	{
		StringBuffer buffer = new StringBuffer("");
		int c;
		
		try
		{
			in.mark(1);
			if (in.read() == -1)
				return null;
			else
				in.reset();
			
			while ((c = in.read()) >= 0)
			{
				if ((c == 0) || (c == '\n') || (c == '\r'))
					break;
				else
					buffer.append((char)c);
			}
		
			if (c == '\r')
			{
				in.mark(1);
				if (in.read() != '\n')
					in.reset();
			}
		}  catch (Exception e)  {
			e.printStackTrace();
		}
		
		return buffer.toString();
	}

	public static byte[] getByteArray (InputStream in) throws IOException {
		ByteArrayOutputStream buffer = new ByteArrayOutputStream();
		
		boolean block = true;
		
		while (block) {
			int b;
			
			try {
				b = in.read();
				buffer.write(b);
			} catch (IOException e) {
				block = false;
			}
			
			if (in.available() == 0)
				block = false;
			
		}
		
		return buffer.toByteArray();
	}
	
	
	public void serviceSocket(Socket s) {

		StringBuffer remoteHostBuffer = new StringBuffer();
		StringBuffer methodTypeBuffer = new StringBuffer();
		String remoteHost = "";
		String methodType = "";
		int contentLen = -1;
		byte[] request = null;
		
		try {
		
			InputStream clientInput = s.getInputStream();
			OutputStream clientOutput = s.getOutputStream();
		
			int remotePort = 80;
			
			request = readRequest (clientInput, remoteHostBuffer, methodTypeBuffer);

			methodType = methodTypeBuffer.toString();
			remoteHost = remoteHostBuffer.toString();
			
	
			if (remoteHost.indexOf(':') != -1) { 
				String[] hostname = StringUtil.split(remoteHost.toString(), ':', 2);
				remoteHost = hostname[0];
				remotePort = Integer.parseInt(hostname[1]);
			}
	
			// We don't support stuff like this.
			if (methodType.equals("CONNECT") || methodType.equals("OPTIONS"))
				return;
	
			Socket remote = new Socket(remoteHost, remotePort);
			
			remote.setSoTimeout(5000);
		//	System.out.println("### " + new String(request));
			
			BufferedInputStream remoteIn = new BufferedInputStream(remote.getInputStream());
			BufferedOutputStream remoteOut = new BufferedOutputStream(remote.getOutputStream());
			
			remoteOut.write(request);
			remoteOut.flush();
			
			StringBuffer header = new StringBuffer();
			boolean inHeader = true;
			int i = 0;
			int responseCode = -1;
			String line = "";
			
			// check response code
			line = readLine(remoteIn);
			if (line != null)
			{
				header.append(line + "\r\n");
				String[] parts = line.split(" ");
				responseCode = Integer.parseInt(parts[1]);	
			}
			
			// get the rest of the header info
			for (;;)
			{
				line = readLine(remoteIn);
				
				if (line == null)
					break;
				
				if (line.length() == 0)
					break;
				
				header.append(line + "\r\n");
				
				if (line.toString().toLowerCase().startsWith("content-length:")) {
					String[] pair = line.toString().trim().split(" ");
					if (pair[1].trim().length() != 0) {
						contentLen = Integer.parseInt(pair[1]);
					}
				}
				
				
			}
			header.append("\r\n");
			
			clientOutput.write(header.toString().getBytes(), 0, header.length());
			
			// if we didn't get 200/OK from server, flush out what did get
			// because we might not get anything else.
			if ((responseCode != 200) && (contentLen == 0)) {
				clientOutput.flush();
			}
			
			// server explicitly told use we're getting nothing.
			if (contentLen == 0) {
				clientOutput.flush();
				return;
			}
				
			byte[] buf = new byte[4096];
			int bytesIn = 0;
			while ( ((contentLen != -1 && i < contentLen) || contentLen == -1) && !remote.isInputShutdown()
					&& ((bytesIn = remoteIn.read(buf)) >= 0) )
			{
				clientOutput.write(buf, 0, bytesIn);
				i += bytesIn;
			}
			
			
			clientOutput.flush();
			
		} catch (Exception e) {
			// silently fail
		}
		
	}
	
	
	
	public byte[] readRequest (InputStream in, StringBuffer remoteHost, StringBuffer methodType) throws IOException {

		ByteArrayOutputStream buffer = new ByteArrayOutputStream();	
		StringBuffer line = new StringBuffer();
	
		for (boolean first = true; first || in.available() > 0; first = false) {
			int b;
			
			try {
				b = in.read();
			} catch (IOException e) {
				// happens when peer disconnects or buffer is empty
				break;
			}
			
			if (b == -1)
				break;
			
			line.append((char) b);
			
			// catch \r\n case
			if (b == '\r') {
				in.mark(1);
				if (in.read() == '\n') {
					//buffer.write('\n');
					line.append('\n');
				} else {
					in.reset();	//oops, it wasn't \r\n, put it back
				}
			}
			
			if ( b == '\r' || b == '\n' ) {					
				if (line.toString().toLowerCase().startsWith("host:")) {
					String[] pair = line.toString().trim().split(" ");
					remoteHost.append(pair[1].trim());
					
					for (int j=0;j<servlets.size();j++) {
						Servlet servlet = (Servlet) servlets.get(j);
						Hashtable hash = servlet.injectHeaders(null);
						
						for (Enumeration e = hash.keys(); e.hasMoreElements();) {
							String key = (String) e.nextElement();
							buffer.write(new String(key + ": " + ((String) hash.get(key)) + "\r\n").getBytes());
						}
					}
					
				} else if (methodType.length() == 0) {
					String[] parts = line.toString().trim().split(" ");
					
					methodType.append(parts[0]);
					
					// Some HTTP servers don't like to be given the absolute URL
					if (parts[1].startsWith("http")) {
						parts[1] = parts[1].substring(parts[1].indexOf("/", 8));
					}
					
					line.setLength(0);
					line.append(parts[0] + " " + parts[1] + " " + parts[2] + "\r\n");
					
					
				} else if (line.toString().toLowerCase().startsWith("proxy-connection:")) {
					// this header was meant for us and not to be forwarded on.
					line.setLength(0);
					continue;
				} 
				
				buffer.write(line.toString().getBytes());
				line.setLength(0);
			}
		
		}
	
		return buffer.toByteArray();
	}
	
	
	
	public static void main(String[] args) {
		ProxyServer proxy = new ProxyServer(2080);
		try {
			proxy.startServer();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
}