gistfile1.txt

package com.thedeanda.servlet;

/*
 * net/balusc/webapp/FileServlet.java
 *
 * Copyright (C) 2009 BalusC
 *
 * This program is free software: you can redistribute it and/or modify it under the terms of the
 * GNU Lesser General Public License as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License along with this library.
 * If not, see <http://www.gnu.org/licenses/>.
 */

import java.io.Closeable;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.zip.GZIPOutputStream;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * A file servlet supporting resume of downloads and client-side caching and
 * GZIP of text content. This servlet can also be used for images, client-side
 * caching would become more efficient. This servlet can also be used for text
 * files, GZIP would decrease network bandwidth.
 * 
 * @author BalusC
 * @link 
 *       http://balusc.blogspot.com/2009/02/fileservlet-supporting-resume-and.html
 */
abstract public class AbstractFileServlet extends HttpServlet {

	// Constants
	// ----------------------------------------------------------------------------------

	private static final long serialVersionUID = 1L;
	private static final int DEFAULT_BUFFER_SIZE = 10240; // ..bytes = 10KB.
	private static final long DEFAULT_EXPIRE_TIME = 604800000L; // ..ms = 1
																// week.
	private static final String MULTIPART_BOUNDARY = "MULTIPART_BYTERANGES";

	/**
	 * Initialize the servlet.
	 * 
	 * @see HttpServlet#init().
	 */
	public void init() throws ServletException {

	}

	abstract public ResponseFile getFile(HttpServletRequest request)
			throws Exception;

	/**
	 * Process HEAD request. This returns the same headers as GET request, but
	 * without content.
	 * 
	 * @see HttpServlet#doHead(HttpServletRequest, HttpServletResponse).
	 */
	protected void doHead(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		// Process request without content.
		processRequest(request, response, false);
	}

	/**
	 * Process GET request.
	 * 
	 * @see HttpServlet#doGet(HttpServletRequest, HttpServletResponse).
	 */
	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		// Process request with content.
		processRequest(request, response, true);
	}

	/**
	 * Process the actual request.
	 * 
	 * @param request
	 *            The request to be processed.
	 * @param response
	 *            The response to be created.
	 * @param content
	 *            Whether the request body should be written (GET) or not
	 *            (HEAD).
	 * @throws IOException
	 *             If something fails at I/O level.
	 */
	private void processRequest(HttpServletRequest request,
			HttpServletResponse response, boolean content) throws IOException {
		// Validate the requested file
		// ------------------------------------------------------------

		// Get requested file by path info.
		// String requestedFile = request.getPathInfo();

		ResponseFile responseFile;
		try {
			responseFile = getFile(request);
		} catch (Exception e) {
			throw new IOException(e);
		}

		// Check if file is actually supplied to the request URL.
		if (responseFile == null || responseFile.getFile() == null
				|| !responseFile.getFile().exists()) {
			// Do your thing if the file is not supplied to the request URL.
			// Throw an exception, or send 404, or show default/warning page, or
			// just ignore it.
			response.sendError(HttpServletResponse.SC_NOT_FOUND);
			return;
		}

		// URL-decode the file name (might contain spaces and on) and prepare
		// file object.
		File file = responseFile.getFile();

		// Check if file actually exists in filesystem.
		if (!file.exists()) {
			// Do your thing if the file appears to be non-existing.
			// Throw an exception, or send 404, or show default/warning page, or
			// just ignore it.
			response.sendError(HttpServletResponse.SC_NOT_FOUND);
			return;
		}

		// Prepare some variables. The ETag is an unique identifier of the file.
		String fileName = file.getName();
		long length = file.length();
		long lastModified = file.lastModified();
		String eTag = responseFile.getEtag();
		if (eTag == null || "".equals(eTag.trim()) || responseFile.isDownload()) {
			eTag = null;
		}

		// Validate request headers for caching
		// ---------------------------------------------------

		// If-None-Match header should contain "*" or ETag. If so, then return
		// 304.
		String ifNoneMatch = request.getHeader("If-None-Match");
		if (eTag != null && ifNoneMatch != null && matches(ifNoneMatch, eTag)) {
			response.setHeader("ETag", eTag); // Required in 304.
			response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
			return;
		}

		// If-Modified-Since header should be greater than LastModified. If so,
		// then return 304.
		// This header is ignored if any If-None-Match header is specified.
		long ifModifiedSince = request.getDateHeader("If-Modified-Since");
		if (eTag != null && ifNoneMatch == null && ifModifiedSince != -1
				&& ifModifiedSince + 1000 > lastModified) {
			response.setHeader("ETag", eTag); // Required in 304.
			response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
			return;
		}

		// Validate request headers for resume
		// ----------------------------------------------------

		// If-Match header should contain "*" or ETag. If not, then return 412.
		String ifMatch = request.getHeader("If-Match");
		if (eTag != null && ifMatch != null && !matches(ifMatch, eTag)) {
			response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED);
			return;
		}

		// If-Unmodified-Since header should be greater than LastModified. If
		// not, then return 412.
		long ifUnmodifiedSince = request.getDateHeader("If-Unmodified-Since");
		if (ifUnmodifiedSince != -1 && ifUnmodifiedSince + 1000 <= lastModified) {
			response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED);
			return;
		}

		// Validate and process range
		// -------------------------------------------------------------

		// Prepare some variables. The full Range represents the complete file.
		Range full = new Range(0, length - 1, length);
		List<Range> ranges = new ArrayList<Range>();

		// Validate and process Range and If-Range headers.
		String range = request.getHeader("Range");
		if (range != null) {

			// Range header should match format "bytes=n-n,n-n,n-n...". If not,
			// then return 416.
			if (!range.matches("^bytes=\\d*-\\d*(,\\d*-\\d*)*$")) {
				response.setHeader("Content-Range", "bytes */" + length); // Required
																			// in
																			// 416.
				response.sendError(HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE);
				return;
			}

			// If-Range header should either match ETag or be greater then
			// LastModified. If not,
			// then return full file.
			String ifRange = request.getHeader("If-Range");
			if (ifRange != null && !ifRange.equals(eTag)) {
				try {
					long ifRangeTime = request.getDateHeader("If-Range"); // Throws
																			// IAE
																			// if
																			// invalid.
					if (ifRangeTime != -1 && ifRangeTime + 1000 < lastModified) {
						ranges.add(full);
					}
				} catch (IllegalArgumentException ignore) {
					ranges.add(full);
				}
			}

			// If any valid If-Range header, then process each part of byte
			// range.
			if (ranges.isEmpty()) {
				for (String part : range.substring(6).split(",")) {
					// Assuming a file with length of 100, the following
					// examples returns bytes at:
					// 50-80 (50 to 80), 40- (40 to length=100), -20
					// (length-20=80 to length=100).
					long start = sublong(part, 0, part.indexOf("-"));
					long end = sublong(part, part.indexOf("-") + 1,
							part.length());

					if (start == -1) {
						start = length - end;
						end = length - 1;
					} else if (end == -1 || end > length - 1) {
						end = length - 1;
					}

					// Check if Range is syntactically valid. If not, then
					// return 416.
					if (start > end) {
						response.setHeader("Content-Range", "bytes */" + length); // Required
																					// in
																					// 416.
						response.sendError(HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE);
						return;
					}

					// Add range.
					ranges.add(new Range(start, end, length));
				}
			}
		}

		// Prepare and initialize response
		// --------------------------------------------------------

		// Get content type by file name and set default GZIP support and
		// content disposition.
		String contentType = null;
		boolean acceptsGzip = false;
		String disposition = "inline";

		if (contentType == null) {
			contentType = getContentType(responseFile);
		}

		if (contentType == null) {
			contentType = getServletContext().getMimeType(fileName);
		}

		// If content type is unknown, then set the default value.
		// For all content types, see:
		// http://www.w3schools.com/media/media_mimeref.asp
		// To add new content types, add new mime-mapping entry in web.xml.
		if (contentType == null) {
			contentType = "application/octet-stream";
		}

		// If content type is text, then determine whether GZIP content encoding
		// is supported by
		// the browser and expand content type with the one and right character
		// encoding.
		if (contentType.startsWith("text")) {
			String acceptEncoding = request.getHeader("Accept-Encoding");
			acceptsGzip = acceptEncoding != null
					&& accepts(acceptEncoding, "gzip");
			contentType += ";charset=UTF-8";
		}

		// Else, expect for images, determine content disposition. If content
		// type is supported by
		// the browser, then set to inline, else attachment which will pop a
		// 'save as' dialogue.
		else if (!contentType.startsWith("image")) {
			String accept = request.getHeader("Accept");
			disposition = accept != null && accepts(accept, contentType) ? "inline"
					: "attachment";
		}

		// force download mode
		if (responseFile.isDownload()) {
			disposition = "attachment";
		}

		// Initialize response.
		response.reset();
		response.setBufferSize(DEFAULT_BUFFER_SIZE);
		if (responseFile.isDownload()) {
			response.setHeader("Content-Disposition", disposition
					+ ";filename=\"" + fileName + "\"");
		}
		response.setHeader("Accept-Ranges", "bytes");
		if (eTag != null)
			response.setHeader("ETag", eTag);
		response.setDateHeader("Last-Modified", lastModified);
		response.setDateHeader("Expires", System.currentTimeMillis()
				+ DEFAULT_EXPIRE_TIME);

		// Send requested file (part(s)) to client
		// ------------------------------------------------

		// Prepare streams.
		RandomAccessFile input = null;
		OutputStream output = null;

		try {
			// Open streams.
			input = new RandomAccessFile(file, "r");
			output = response.getOutputStream();

			if (ranges.isEmpty() || ranges.get(0) == full) {

				// Return full file.
				Range r = full;
				response.setContentType(contentType);
				response.setHeader("Content-Range", "bytes " + r.start + "-"
						+ r.end + "/" + r.total);

				if (content) {
					if (acceptsGzip) {
						// The browser accepts GZIP, so GZIP the content.
						response.setHeader("Content-Encoding", "gzip");
						output = new GZIPOutputStream(output,
								DEFAULT_BUFFER_SIZE);
					} else {
						// Content length is not directly predictable in case of
						// GZIP.
						// So only add it if there is no means of GZIP, else
						// browser will hang.
						response.setHeader("Content-Length",
								String.valueOf(r.length));
					}

					// Copy full range.
					copy(input, output, r.start, r.length);
				}

			} else if (ranges.size() == 1) {

				// Return single part of file.
				Range r = ranges.get(0);
				response.setContentType(contentType);
				response.setHeader("Content-Range", "bytes " + r.start + "-"
						+ r.end + "/" + r.total);
				response.setHeader("Content-Length", String.valueOf(r.length));
				response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT); // 206.

				if (content) {
					// Copy single part range.
					copy(input, output, r.start, r.length);
				}

			} else {

				// Return multiple parts of file.
				response.setContentType("multipart/byteranges; boundary="
						+ MULTIPART_BOUNDARY);
				response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT); // 206.

				if (content) {
					// Cast back to ServletOutputStream to get the easy println
					// methods.
					ServletOutputStream sos = (ServletOutputStream) output;

					// Copy multi part range.
					for (Range r : ranges) {
						// Add multipart boundary and header fields for every
						// range.
						sos.println();
						sos.println("--" + MULTIPART_BOUNDARY);
						sos.println("Content-Type: " + contentType);
						sos.println("Content-Range: bytes " + r.start + "-"
								+ r.end + "/" + r.total);

						// Copy single part range of multi part range.
						copy(input, output, r.start, r.length);
					}

					// End with multipart boundary.
					sos.println();
					sos.println("--" + MULTIPART_BOUNDARY + "--");
				}
			}
		} finally {
			// Gently close streams.
			close(output);
			close(input);
		}
	}

	// Helpers (can be refactored to public utility class)
	// ----------------------------------------

	/**
	 * Returns true if the given accept header accepts the given value.
	 * 
	 * @param acceptHeader
	 *            The accept header.
	 * @param toAccept
	 *            The value to be accepted.
	 * @return True if the given accept header accepts the given value.
	 */
	private static boolean accepts(String acceptHeader, String toAccept) {
		String[] acceptValues = acceptHeader.split("\\s*(,|;)\\s*");
		Arrays.sort(acceptValues);
		return Arrays.binarySearch(acceptValues, toAccept) > -1
				|| Arrays.binarySearch(acceptValues,
						toAccept.replaceAll("/.*$", "/*")) > -1
				|| Arrays.binarySearch(acceptValues, "*/*") > -1;
	}

	/**
	 * Returns true if the given match header matches the given value.
	 * 
	 * @param matchHeader
	 *            The match header.
	 * @param toMatch
	 *            The value to be matched.
	 * @return True if the given match header matches the given value.
	 */
	private static boolean matches(String matchHeader, String toMatch) {
		String[] matchValues = matchHeader.split("\\s*,\\s*");
		Arrays.sort(matchValues);
		return Arrays.binarySearch(matchValues, toMatch) > -1
				|| Arrays.binarySearch(matchValues, "*") > -1;
	}

	/**
	 * Returns a substring of the given string value from the given begin index
	 * to the given end index as a long. If the substring is empty, then -1 will
	 * be returned
	 * 
	 * @param value
	 *            The string value to return a substring as long for.
	 * @param beginIndex
	 *            The begin index of the substring to be returned as long.
	 * @param endIndex
	 *            The end index of the substring to be returned as long.
	 * @return A substring of the given string value as long or -1 if substring
	 *         is empty.
	 */
	private static long sublong(String value, int beginIndex, int endIndex) {
		String substring = value.substring(beginIndex, endIndex);
		return (substring.length() > 0) ? Long.parseLong(substring) : -1;
	}

	/**
	 * Copy the given byte range of the given input to the given output.
	 * 
	 * @param input
	 *            The input to copy the given range to the given output for.
	 * @param output
	 *            The output to copy the given range from the given input for.
	 * @param start
	 *            Start of the byte range.
	 * @param length
	 *            Length of the byte range.
	 * @throws IOException
	 *             If something fails at I/O level.
	 */
	private static void copy(RandomAccessFile input, OutputStream output,
			long start, long length) throws IOException {
		byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
		int read;

		if (input.length() == length) {
			// Write full range.
			while ((read = input.read(buffer)) > 0) {
				output.write(buffer, 0, read);
			}
		} else {
			// Write partial range.
			input.seek(start);
			long toRead = length;

			while ((read = input.read(buffer)) > 0) {
				if ((toRead -= read) > 0) {
					output.write(buffer, 0, read);
				} else {
					output.write(buffer, 0, (int) toRead + read);
					break;
				}
			}
		}
	}

	/**
	 * Close the given resource.
	 * 
	 * @param resource
	 *            The resource to be closed.
	 */
	private static void close(Closeable resource) {
		if (resource != null) {
			try {
				resource.close();
			} catch (IOException ignore) {
				// Ignore IOException. If you want to handle this anyway, it
				// might be useful to know
				// that this will generally only be thrown when the client
				// aborted the request.
			}
		}
	}

	// Inner classes
	// ------------------------------------------------------------------------------

	/**
	 * This class represents a byte range.
	 */
	protected class Range {
		long start;
		long end;
		long length;
		long total;

		/**
		 * Construct a byte range.
		 * 
		 * @param start
		 *            Start of the byte range.
		 * @param end
		 *            End of the byte range.
		 * @param total
		 *            Total length of the byte source.
		 */
		public Range(long start, long end, long total) {
			this.start = start;
			this.end = end;
			this.length = end - start + 1;
			this.total = total;
		}

	}

	protected String getContentType(ResponseFile responseFile) {
		String ret = null;
		String fn = responseFile.getFile().getName().toLowerCase();
		fn = fn.substring(fn.lastIndexOf(".") + 1);

		Map<String, String> map = new HashMap<String, String>();
		map.put("mp4", "video/mp4");
		map.put("wmv", "video/x-ms-wmv");
		map.put("flv", "video/x-flv");
		map.put("mpeg", "video/mpeg");
		map.put("mpg", "video/mpeg");
		map.put("mkv", "video/matroska");
		map.put("ogv", "video/ogg");

		map.put("css", "text/css");
		map.put("csv", "text/cvs");
		map.put("html", "text/html");
		map.put("txt", "text/plain");
		map.put("xml", "text/xml");

		map.put("gif", "image/gif");
		map.put("jpeg", "image/jpeg");
		map.put("jpg", "image/jpeg");
		map.put("png", "image/png");
		map.put("svg", "image/svg+xml");
		map.put("tiff", "image/tiff");

		map.put("aac", "audio/x-aac");
		map.put("mp3", "audio/mpeg");
		map.put("ogg", "audio/ogg");
		map.put("ra", "audio/vnc.rn-realaudio");
		map.put("wav", "audio/vnc.wave");

		map.put("json", "application/json");
		map.put("js", "application/javascript");
		map.put("pdf", "application/pdf");
		map.put("ps", "application/postscript");
		map.put("rss", "application/rss+xml");
		map.put("zip", "application/zip");
		map.put("gz", "application/gzip");
		map.put("rar", "application/x-rar-compressed");
		map.put("tar", "application/x-tar");

		map.put("xls", "application/vnd.ms-excel");
		map.put("xlt", "application/vnd.ms-excel");
		map.put("xla", "application/vnd.ms-excel");
		map.put("ppt", "application/vnd.ms-powerpoint");
		map.put("pot", "application/vnd.ms-powerpoint");
		map.put("pps", "application/vnd.ms-powerpoint");
		map.put("ppa", "application/vnd.ms-powerpoint");
		map.put("doc", "application/msword");
		map.put("odt", "application/vnd.oasis.opendocument.text");
		map.put("docx",
				"application/vnd.openxmlformats-officedocument.wordprocessingml.document");
		map.put("xlsx",
				"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
		map.put("xltx",
				"application/vnd.openxmlformats-officedocument.spreadsheetml.template");
		map.put("pptx",
				"application/vnd.openxmlformats-officedocument.presentationml.presentation");
		map.put("potx",
				"application/vnd.openxmlformats-officedocument.presentationml.template");
		map.put("ppsx",
				"application/vnd.openxmlformats-officedocument.presentationml.slideshow");

		ret = map.get(fn);

		return ret;
	}
}





package com.thedeanda.servlet;

import java.io.File;

public class ResponseFile {
	private File file;
	private boolean download;
	private String etag;

	public String getEtag() {
		return etag;
	}

	public void setEtag(String etag) {
		this.etag = etag;
	}

	public boolean isDownload() {
		return download;
	}

	public void setDownload(boolean download) {
		this.download = download;
	}

	public File getFile() {
		return file;
	}

	public void setFile(File file) {
		this.file = file;
	}

}