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Thread: How to properly return a gzip encoded http request

  1. #1
    Junior Member
    Join Date
    Jan 2013
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    Default How to properly return a gzip encoded http request

    Hello everyone,

    I'm currently working on my home automation project.
    the project required me to write my own "simple" webserver.

    i have some code to detect that the webbrowser accepts gzip encoding.
    if the browser supports it, i return gzip encoded websites but they seem to be rubbish since my browser (chrome) can't seem to display them.

    public byte[] getHTTPPage(HTTPRequestHandler request, String name, Hashtable<String, String> headers, Hashtable<String, String> parameters) throws UnsupportedEncodingException, IOException {
            if (CacheManager.getInstance().isCached(name, HTTPServer.getSessionID(parameters))) {
                return CacheManager.getInstance().getCache(name, HTTPServer.getSessionID(parameters)).getData();
            } else {
                BufferedReader reader = null;
                ByteArrayOutputStream bout = new ByteArrayOutputStream();
                InputStream resource;
                BufferedInputStream input = null;
                boolean isImage = false;
                boolean useGZip = false;
                useGZip = HTTPServer.isGZipEnabled(headers);
                if (name.endsWith(".do")) {
                    return HTTPServer.toByteArray(_generateHTTPPage(request, name, parameters));
                } else if (this.getClass().getResource(resourceLocation + name) == null) {
                    return new byte[0];
                try {
                    resource = this.getClass().getResourceAsStream(resourceLocation + name);
                    if (!isImage(name)) {
                        reader = new BufferedReader(new InputStreamReader(resource));
                        while (reader.ready()) {
                            if (!isImage) {
                                bout.write(HTTPServer.toByteArray(reader.readLine() + "\r\n"));
                            } else {
                    } else {
                        byte[] buffer = new byte[1024];
                        input = new BufferedInputStream(resource);
                        int length = -1;
                        while ((length = input.read(buffer, 0, buffer.length)) > -1) {
                            bout.write(buffer, 0, length);
                } catch (FileNotFoundException ex) {
                    return null;
                } finally {
                    try {
                        if (reader != null) {
                    } catch (IOException ex) {
                    try {
                        if (input != null) {
                    } catch (IOException ex) {
                    if (useGZip) {
                        ByteArrayOutputStream temp = new ByteArrayOutputStream();
                        temp = null;
                    CacheManager.getInstance().cache(name, bout.toByteArray(), HTTPServer.getSessionID(parameters));
                    return bout.toByteArray();
    public static byte[] encodeToGZip(byte[] data) {
            ByteArrayOutputStream bos = null;
            GZIPOutputStream output = null;
            try {
                bos = new ByteArrayOutputStream();
                output = new GZIPOutputStream(bos);
                return Base64.encodeBase64(bos.toByteArray());
    //            return bos.toByteArray();
            } catch (IOException ex) {
            //return bos.toByteArray();
            return null;
    public static byte[] toByteArray(String data) throws UnsupportedEncodingException {
            return data.getBytes("utf-8");

    i'm not sure why it doesn't work.

  2. #2
    Administrator copeg's Avatar
    Join Date
    Oct 2009
    Thanked 832 Times in 772 Posts
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    Default Re: How to properly return a gzip encoded http request

    Your code has a lot of classes that are not part of J2SE, so its difficult to comment on a lot of it. That being said, if you wish the browser to download a file make sure you are sending the appropriate header's to the browser - you should send the appropriate Content-Type header information. See
    HTTP/1.1: Header Field Definitions
    MIME - Wikipedia, the free encyclopedia

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