FileSrv.java

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

public class FileSrv {
	
	public static void main(String[] args) throws IOException{
		
		int port = 3333;
		ServerSocket ssock = new ServerSocket(port);
		System.out.println("FILE server, running on port " + port + "...");
		
		final String crlf = "\r\n";
		final String crlf2 = crlf + crlf;
		while (true) {
			
			System.out.println("\nstarting to wait for new clients again...\n");
			
			Socket sock = ssock.accept();
			System.out.println("at "+ new Date() + ", new client connection!");
			
			//PrintWriter out = new PrintWriter(sock.getOutputStream(), true);
			OutputStream out = sock.getOutputStream();
			InputStreamReader in = new InputStreamReader(sock.getInputStream());
			
			String req = "";
			for (int b = in.read(); b != -1; b = in.read()) {
				char c = (char)b;
				req += c;
				if (req.endsWith(crlf2)) break;
			}
			System.out.println("req from client:\n" + req);
			String firstLine = req.split(crlf)[0];
			// needed for firefox b/c it sends an empty tcp message as you type in the url bar
			if (firstLine.equals("")) {
				System.out.println("recieved EMPTY tcp msg, skipping\n");
				out.flush();
				in.close();
				out.close();
				sock.close();
				continue;
			}
			String res = firstLine.split(" ")[1];
			System.out.println("file requested: " + res);
			
			String body = "HI browser \n\nI think you asked for file " + res;
			
			Path pathFile = Paths.get("." + res);
			boolean exists = Files.exists(pathFile);
			
			byte[] content;
			String status;
			if (exists) {
				status = "OK 200";
				body += ", and it's there!";
				content = Files.readAllBytes(pathFile);
			} else {
				status = "404 File Not Found";
				body += ", IT'S NOT THERE!!";
				content = body.getBytes();
			}
			
			String head = "HTTP/1.1 " + status + crlf + "Content-Length: " + body.length() + crlf2;
			
			String resp = head+body;
			System.out.println("sending resp to client: \n" + resp);
			//out.println(resp);
			out.write(head.getBytes());
			out.write(content);
		}
	}

}