HttpStaticFileServerHandler Class — netty Architecture

Source Code

example/src/main/java/io/netty/example/http/file/HttpStaticFileServerHandler.java lines 107–422

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 FullHttpRequest request;

    @Override
    public void channelRead0(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception {
        this.request = request;
        if (!request.decoderResult().isSuccess()) {
            sendError(ctx, BAD_REQUEST);
            return;
        }

        if (!GET.equals(request.method())) {
            sendError(ctx, METHOD_NOT_ALLOWED);
            return;
        }

        final boolean keepAlive = HttpUtil.isKeepAlive(request);
        final String uri = request.uri();
        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, uri);
            } else {
                sendRedirect(ctx, uri + '/');
            }
            return;
        }

        if (!file.isFile()) {
            sendError(ctx, FORBIDDEN);
            return;
        }

        // Cache Validation
        String ifModifiedSince = request.headers().get(HttpHeaderNames.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 ignore) {
            sendError(ctx, NOT_FOUND);
            return;
        }
        long fileLength = raf.length();

        HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK);
        HttpUtil.setContentLength(response, fileLength);
        setContentTypeHeader(response, file);
        setDateAndCacheHeaders(response, file);

        if (!keepAlive) {
            response.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.CLOSE);