package webserver.netty;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelProgressiveFuture;
import io.netty.channel.ChannelProgressiveFutureListener;
import io.netty.channel.DefaultFileRegion;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.DefaultHttpResponse;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.FullHttpResponse;
import io.netty.handler.codec.http.HttpHeaders;
import io.netty.handler.codec.http.HttpResponse;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.LastHttpContent;
import io.netty.handler.stream.ChunkedFile;
import io.netty.util.CharsetUtil;
import io.netty.util.internal.SystemPropertyUtil;
import javax.activation.MimetypesFileTypeMap;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.RandomAccessFile;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.TimeZone;
import java.util.regex.Pattern;
import static io.netty.handler.codec.http.HttpHeaders.Names.*;
import static io.netty.handler.codec.http.HttpHeaders.*;
import static io.netty.handler.codec.http.HttpMethod.*;
import static io.netty.handler.codec.http.HttpResponseStatus.*;
import static io.netty.handler.codec.http.HttpVersion.*;
/**
* A simple handler that serves incoming HTTP requests to send their respective
* HTTP responses. It also implements {@code 'If-Modified-Since'} header to
* take advantage of browser cache, as described in
* <a href="http://tools.ietf.org/html/rfc2616#section-14.25">RFC 2616</a>.
*
* <h3>How Browser Caching Works</h3>
*
* Web browser caching works with HTTP headers as illustrated by the following
* sample:
* <ol>
* <li>Request #1 returns the content of {@code /file1.txt}.</li>
* <li>Contents of {@code /file1.txt} is cached by the browser.</li>
* <li>Request #2 for {@code /file1.txt} does return the contents of the
* file again. Rather, a 304 Not Modified is returned. This tells the
* browser to use the contents stored in its cache.</li>
* <li>The server knows the file has not been modified because the
* {@code If-Modified-Since} date is the same as the file's last
* modified date.</li>
* </ol>
*
* <pre>
* Request #1 Headers
* ===================
* GET /file1.txt HTTP/1.1
*
* Response #1 Headers
* ===================
* HTTP/1.1 200 OK
* Date: Tue, 01 Mar 2011 22:44:26 GMT
* Last-Modified: Wed, 30 Jun 2010 21:36:48 GMT
* Expires: Tue, 01 Mar 2012 22:44:26 GMT
* Cache-Control: private, max-age=31536000
*
* Request #2 Headers
* ===================
* GET /file1.txt HTTP/1.1
* If-Modified-Since: Wed, 30 Jun 2010 21:36:48 GMT
*
* Response #2 Headers
* ===================
* HTTP/1.1 304 Not Modified
* Date: Tue, 01 Mar 2011 22:44:28 GMT
*
* </pre>
*/
public class HttpStaticFileServerHandler extends SimpleChannelInboundHandler<FullHttpRequest> {
public static final String HTTP_DATE_FORMAT = "EEE, dd MMM yyyy HH:mm:ss zzz";
public static final String HTTP_DATE_GMT_TIMEZONE = "GMT";
public static final int HTTP_CACHE_SECONDS = 60;
private final boolean useSendFile;
public HttpStaticFileServerHandler(boolean useSendFile) {
this.useSendFile = useSendFile;
}
@Override
public void channelRead0(
ChannelHandlerContext ctx, FullHttpRequest request) throws Exception {
if (!request.getDecoderResult().isSuccess()) {
sendError(ctx, BAD_REQUEST);
return;
}
if (request.getMethod() != GET) {
sendError(ctx, METHOD_NOT_ALLOWED);
return;
}
final String uri = request.getUri();
final String path = sanitizeUri(uri);
if (path == null) {
sendError(ctx, FORBIDDEN);
return;
}
File file = new File(path);
if (file.isHidden() || !file.exists()) {
sendError(ctx, NOT_FOUND);
return;
}
if (file.isDirectory()) {
if (uri.endsWith("/")) {
sendListing(ctx, file);
} else {
sendRedirect(ctx, uri + '/');
}
return;
}
if (!file.isFile()) {
sendError(ctx, FORBIDDEN);
return;
}
// Cache Validation
String ifModifiedSince = request.headers().get(IF_MODIFIED_SINCE);
if (ifModifiedSince != null && !ifModifiedSince.isEmpty()) {
SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT, Locale.US);
Date ifModifiedSinceDate = dateFormatter.parse(ifModifiedSince);
// Only compare up to the second because the datetime format we send to the client
// does not have milliseconds
long ifModifiedSinceDateSeconds = ifModifiedSinceDate.getTime() / 1000;
long fileLastModifiedSeconds = file.lastModified() / 1000;
if (ifModifiedSinceDateSeconds == fileLastModifiedSeconds) {
sendNotModified(ctx);
return;
}
}
RandomAccessFile raf;
try {
raf = new RandomAccessFile(file, "r");
} catch (FileNotFoundException fnfe) {
sendError(ctx, NOT_FOUND);
return;
}
long fileLength = raf.length();
HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK);
setContentLength(response, fileLength);
setContentTypeHeader(response, file);
setDateAndCacheHeaders(response, file);
if (isKeepAlive(request)) {
response.headers().set(CONNECTION, HttpHeaders.Values.KEEP_ALIVE);
}
// Write the initial line and the header.
ctx.write(response);
// Write the content.
ChannelFuture sendFileFuture;
if (useSendFile) {
sendFileFuture =
ctx.write(new DefaultFileRegion(raf.getChannel(), 0, fileLength), ctx.newProgressivePromise());
} else {
sendFileFuture =
ctx.write(new ChunkedFile(raf, 0, fileLength, 8192), ctx.newProgressivePromise());
}
sendFileFuture.addListener(new ChannelProgressiveFutureListener() {
@Override
public void operationProgressed(ChannelProgressiveFuture future, long progress, long total) {
if (total < 0) { // total unknown
System.err.println("Transfer progress: " + progress);
} else {
System.err.println("Transfer progress: " + progress + " / " + total);
}
}
@Override
public void operationComplete(ChannelProgressiveFuture future) throws Exception {
System.err.println("Transfer complete.");
}
});
// Write the end marker
ChannelFuture lastContentFuture = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);
// Decide whether to close the connection or not.
if (!isKeepAlive(request)) {
// Close the connection when the whole content is written out.
lastContentFuture.addListener(ChannelFutureListener.CLOSE);
}
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
if (ctx.channel().isActive()) {
sendError(ctx, INTERNAL_SERVER_ERROR);
}
}
private static final Pattern INSECURE_URI = Pattern.compile(".*[<>&\"].*");
private static String sanitizeUri(String uri) {
// Decode the path.
try {
uri = URLDecoder.decode(uri, "UTF-8");
} catch (UnsupportedEncodingException e) {
try {
uri = URLDecoder.decode(uri, "ISO-8859-1");
} catch (UnsupportedEncodingException e1) {
throw new Error();
}
}
if (!uri.startsWith("/")) {
return null;
}
// Convert file separators.
uri = uri.replace('/', File.separatorChar);
// Simplistic dumb security check.
// You will have to do something serious in the production environment.
if (uri.contains(File.separator + '.') ||
uri.contains('.' + File.separator) ||
uri.startsWith(".") || uri.endsWith(".") ||
INSECURE_URI.matcher(uri).matches()) {
return null;
}
// Convert to absolute path.
return SystemPropertyUtil.get("user.dir") + File.separator + uri;
}
private static final Pattern ALLOWED_FILE_NAME = Pattern.compile("[A-Za-z0-9][-_A-Za-z0-9\\.]*");
private static void sendListing(ChannelHandlerContext ctx, File dir) {
FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK);
response.headers().set(CONTENT_TYPE, "text/html; charset=UTF-8");
StringBuilder buf = new StringBuilder();
String dirPath = dir.getPath();
buf.append("<!DOCTYPE html>\r\n");
buf.append("<html><head><title>");
buf.append("Listing of: ");
buf.append(dirPath);
buf.append("</title></head><body>\r\n");
buf.append("<h3>Listing of: ");
buf.append(dirPath);
buf.append("</h3>\r\n");
buf.append("<ul>");
buf.append("<li><a href=\"../\">..</a></li>\r\n");
for (File f: dir.listFiles()) {
if (f.isHidden() || !f.canRead()) {
continue;
}
String name = f.getName();
if (!ALLOWED_FILE_NAME.matcher(name).matches()) {
continue;
}
buf.append("<li><a href=\"");
buf.append(name);
buf.append("\">");
buf.append(name);
buf.append("</a></li>\r\n");
}
buf.append("</ul></body></html>\r\n");
ByteBuf buffer = Unpooled.copiedBuffer(buf, CharsetUtil.UTF_8);
response.content().writeBytes(buffer);
buffer.release();
// Close the connection as soon as the error message is sent.
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
private static void sendRedirect(ChannelHandlerContext ctx, String newUri) {
FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, FOUND);
response.headers().set(LOCATION, newUri);
// Close the connection as soon as the error message is sent.
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
// ERROR PAGE: 404
private static void sendError(ChannelHandlerContext ctx, HttpResponseStatus status) {
FullHttpResponse response = new DefaultFullHttpResponse(
HTTP_1_1, status, Unpooled.copiedBuffer("Failure: " + status.toString() + "\r\n", CharsetUtil.UTF_8));
response.headers().set(CONTENT_TYPE, "text/plain; charset=UTF-8");
// Close the connection as soon as the error message is sent.
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
/**
* When file timestamp is the same as what the browser is sending up, send a "304 Not Modified"
*
* @param ctx
* Context
*/
private static void sendNotModified(ChannelHandlerContext ctx) {
FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, NOT_MODIFIED);
setDateHeader(response);
// Close the connection as soon as the error message is sent.
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
/**
* Sets the Date header for the HTTP response
*
* @param response
* HTTP response
*/
private static void setDateHeader(FullHttpResponse response) {
SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT, Locale.US);
dateFormatter.setTimeZone(TimeZone.getTimeZone(HTTP_DATE_GMT_TIMEZONE));
Calendar time = new GregorianCalendar();
response.headers().set(DATE, dateFormatter.format(time.getTime()));
}
/**
* Sets the Date and Cache headers for the HTTP Response
*
* @param response
* HTTP response
* @param fileToCache
* file to extract content type
*/
private static void setDateAndCacheHeaders(HttpResponse response, File fileToCache) {
SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT, Locale.US);
dateFormatter.setTimeZone(TimeZone.getTimeZone(HTTP_DATE_GMT_TIMEZONE));
// Date header
Calendar time = new GregorianCalendar();
response.headers().set(DATE, dateFormatter.format(time.getTime()));
// Add cache headers
time.add(Calendar.SECOND, HTTP_CACHE_SECONDS);
response.headers().set(EXPIRES, dateFormatter.format(time.getTime()));
response.headers().set(CACHE_CONTROL, "private, max-age=" + HTTP_CACHE_SECONDS);
response.headers().set(
LAST_MODIFIED, dateFormatter.format(new Date(fileToCache.lastModified())));
}
/**
* Sets the content type header for the HTTP Response
*
* @param response
* HTTP response
* @param file
* file to extract content type
*/
private static void setContentTypeHeader(HttpResponse response, File file) {
MimetypesFileTypeMap mimeTypesMap = new MimetypesFileTypeMap();
response.headers().set(CONTENT_TYPE, mimeTypesMap.getContentType(file.getPath()));
}
}