home | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Java example source code file (ChunkedEncoding.java)

This example Java source code file (ChunkedEncoding.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

bufferedoutputstream, checksum, chunkedencoding, content\-type, exception, inputstream, net, network, printstream, random, serversocket, string, trailer, transfer\-encoding, url, util

The ChunkedEncoding.java Java example source code

/*
 * Copyright (c) 2001, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/**
 *
 * @bug 4333920
 * @bug 4394548
 * @summary Check that chunked encoding response doesn't cause
 *          getInputStream to block until last chunk arrives.
 *          Also regression against NPE in ChunkedInputStream.
 */
import java.net.*;
import java.io.*;
import java.util.Random;

public class ChunkedEncoding implements Runnable {

    ServerSocket ss;

    /*
     * Our "http" server to return a chunked response
     */
    public void run() {
        try {
            Socket s = ss.accept();

            PrintStream out = new PrintStream(
                                 new BufferedOutputStream(
                                    s.getOutputStream() ));

            /* send the header */
            out.print("HTTP/1.1 200\r\n");
            out.print("Transfer-Encoding: chunked\r\n");
            out.print("Content-Type: text/html\r\n");
            out.print("\r\n");
            out.flush();

            /* delay the server before first chunk */
            Thread.sleep(5000);

            /*
             * Our response will be of random length
             * but > 32k
             */
            Random rand = new Random();

            int len;
            do {
                len = rand.nextInt(128*1024);
            } while (len < 32*1024);

            /*
             * Our chunk size will be 2-32k
             */
            int chunkSize;
            do {
                chunkSize = rand.nextInt(len / 3);
            } while (chunkSize < 2*1024);

            /*
             * Generate random content and check sum it
             */
            byte buf[] = new byte[len];
            int cs = 0;
            for (int i=0; i<len; i++) {
                buf[i] = (byte)('a' + rand.nextInt(26));
                cs = (cs + buf[i]) % 65536;
            }

            /*
             * Stream the chunks to the client
             */
            int remaining = len;
            int pos = 0;
            while (remaining > 0) {
                int size = Math.min(remaining, chunkSize);
                out.print( Integer.toHexString(size) );
                out.print("\r\n");
                out.write( buf, pos, size );
                pos += size;
                remaining -= size;
                out.print("\r\n");
                out.flush();
            }

            /* send EOF chunk */
            out.print("0\r\n");
            out.flush();

            /*
             * Send trailer with checksum
             */
            String trailer = "Checksum:" + cs + "\r\n";
            out.print(trailer);
            out.print("\r\n");
            out.flush();

            s.close();
            ss.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    ChunkedEncoding() throws Exception {

        /* start the server */
        ss = new ServerSocket(0);
        (new Thread(this)).start();

        /* establish http connection to server */
        String uri = "http://localhost:" +
                     Integer.toString(ss.getLocalPort()) +
                     "/foo";
        URL url = new URL(uri);
        HttpURLConnection http = (HttpURLConnection)url.openConnection();

        /*
         * Server should only send headers if TE:trailers
         * specified - see updated HTTP 1.1 spec.
         */
        http.setRequestProperty("TE", "trailers");

        /* Time how long the getInputStream takes */
        long ts = System.currentTimeMillis();
        InputStream in = http.getInputStream();
        long te = System.currentTimeMillis();

        /*
         * If getInputStream takes >2 seconds it probably means
         * that the implementation is waiting for the chunks to
         * arrive.
         */
        if ( (te-ts) > 2000) {
            throw new Exception("getInputStream didn't return immediately");
        }

        /*
         * Read the stream and checksum it as it arrives
         */
        int nread;
        int cs = 0;
        byte b[] = new byte[1024];
        do {
            nread = in.read(b);
            if (nread > 0) {
                for (int i=0; i<nread; i++) {
                    cs = (cs + b[i]) % 65536;
                }
            }
        } while (nread > 0);

        /*
         * Verify that the checksums match
         */
        String trailer = http.getHeaderField("Checksum");
        if (trailer == null) {
            throw new Exception("Checksum trailer missing from response");
        }
        int rcvd_cs = Integer.parseInt(trailer);
        if (rcvd_cs != cs) {
            throw new Exception("Trailer checksum doesn't equal calculated checksum");
        }

        http.disconnect();

    }

    public static void main(String args[]) throws Exception {
        new ChunkedEncoding();
    }

}

Other Java examples (source code examples)

Here is a short list of links related to this Java ChunkedEncoding.java source code file:



my book on functional programming

 

new blog posts

 

Copyright 1998-2019 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.