gabrielb/FilesListServlet

## FilesListServlet
package com.fileNotRequested;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class FilesListServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        try (PrintWriter out = response.getWriter()) {
            out.println("<!DOCTYPE html>");
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Files Not Requested</title>");
            out.println("</head>");
            out.println("<body>");
            out.println("<h1>Files Not Requested</h1>");
            out.println("</ul>");
            for (String file : FilesNotRequestedFilter.FILES) {
                out.println("<li>" + file + "</li>");
            }
            out.println("</ul>");
            out.println("</body>");
            out.println("</html>");
        }
    }

}

## FilesNotRequestedFilter
package com.fileNotRequested;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.HashSet;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

public class FilesNotRequestedFilter implements Filter {

    public static final HashSet<String> FILES = new HashSet<>();

    private static final String FOLDER = "/";

    private static final String URI = "/FilesNotRequested/";

    private static boolean ERROR = false;

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {

        if (FILES.isEmpty()) {
            populateFileList(request);
        }

        if (request instanceof HttpServletRequest) {
            HttpServletRequest httpRequest = (HttpServletRequest) request;
            String fileUrl = httpRequest.getRequestURI().substring(URI.length());
            FILES.remove("/" + fileUrl);
        }

        chain.doFilter(request, response);

    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override
    public void destroy() {
    }

    private static void populateFileList(ServletRequest request) {

        if (ERROR) {
            return;
        }

        try {
            URL resource = request.getServletContext().getResource(FOLDER);
            File rootFile = new File(resource.toURI());
            populateFileList(rootFile, rootFile);
        } catch (Exception ex) {
            ERROR = true;
        }
    }

    private static void populateFileList(File folder, File root) {
        File[] list = folder.listFiles();
        if (list == null) {
            return;
        }
        for (File f : list) {
            if (f.isDirectory()) {
                populateFileList(f, root);
            } else {
                FILES.add(f.getAbsolutePath().substring(root.getAbsolutePath().length()));
            }
        }
    }

}
	package com.fileNotRequested;

	import java.io.IOException;
	import java.io.PrintWriter;
	import javax.servlet.ServletException;
	import javax.servlet.http.HttpServlet;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletResponse;

	public class FilesListServlet extends HttpServlet {

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	response.setContentType("text/html;charset=UTF-8");
	try (PrintWriter out = response.getWriter()) {
	out.println("<!DOCTYPE html>");
	out.println("<html>");
	out.println("<head>");
	out.println("<title>Files Not Requested</title>");
	out.println("</head>");
	out.println("<body>");
	out.println("<h1>Files Not Requested</h1>");
	out.println("</ul>");
	for (String file : FilesNotRequestedFilter.FILES) {
	out.println("<li>" + file + "</li>");
	}
	out.println("</ul>");
	out.println("</body>");
	out.println("</html>");
	}
	}

	}
	package com.fileNotRequested;

	import java.io.File;
	import java.io.IOException;
	import java.net.URL;
	import java.util.HashSet;
	import javax.servlet.Filter;
	import javax.servlet.FilterChain;
	import javax.servlet.FilterConfig;
	import javax.servlet.ServletException;
	import javax.servlet.ServletRequest;
	import javax.servlet.ServletResponse;
	import javax.servlet.http.HttpServletRequest;

	public class FilesNotRequestedFilter implements Filter {

	public static final HashSet<String> FILES = new HashSet<>();

	private static final String FOLDER = "/";

	private static final String URI = "/FilesNotRequested/";

	private static boolean ERROR = false;

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {

	if (FILES.isEmpty()) {
	populateFileList(request);
	}

	if (request instanceof HttpServletRequest) {
	HttpServletRequest httpRequest = (HttpServletRequest) request;
	String fileUrl = httpRequest.getRequestURI().substring(URI.length());
	FILES.remove("/" + fileUrl);
	}

	chain.doFilter(request, response);

	}

	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
	}

	@Override
	public void destroy() {
	}

	private static void populateFileList(ServletRequest request) {

	if (ERROR) {
	return;
	}

	try {
	URL resource = request.getServletContext().getResource(FOLDER);
	File rootFile = new File(resource.toURI());
	populateFileList(rootFile, rootFile);
	} catch (Exception ex) {
	ERROR = true;
	}
	}

	private static void populateFileList(File folder, File root) {
	File[] list = folder.listFiles();
	if (list == null) {
	return;
	}
	for (File f : list) {
	if (f.isDirectory()) {
	populateFileList(f, root);
	} else {
	FILES.add(f.getAbsolutePath().substring(root.getAbsolutePath().length()));
	}
	}
	}

	}