HttpContentCompressor Class — netty Architecture

Source Code

codec-http/src/main/java/io/netty/handler/codec/http/HttpContentCompressor.java lines 51–446

public class HttpContentCompressor extends HttpContentEncoder {

    private final BrotliOptions brotliOptions;
    private final GzipOptions gzipOptions;
    private final DeflateOptions deflateOptions;
    private final ZstdOptions zstdOptions;
    private final SnappyOptions snappyOptions;

    private final int contentSizeThreshold;
    private ChannelHandlerContext ctx;

    private static final CompressionOptions[] DEFAULT_COMPRESSION_OPTIONS;
    static {
        List<CompressionOptions> options = new ArrayList<>(5);
        options.add(StandardCompressionOptions.gzip());
        options.add(StandardCompressionOptions.deflate());
        options.add(StandardCompressionOptions.snappy());
        if (Brotli.isAvailable()) {
            options.add(StandardCompressionOptions.brotli());
        }
        if (Zstd.isAvailable()) {
            options.add(StandardCompressionOptions.zstd());
        }
        DEFAULT_COMPRESSION_OPTIONS = options.toArray(new CompressionOptions[0]);
    }

    /**
     * Creates a new handler with {@link StandardCompressionOptions#brotli()} (if supported) ,
     * {@link StandardCompressionOptions#zstd()} (if supported), {@link StandardCompressionOptions#snappy()},
     * {@link StandardCompressionOptions#gzip()} and {@link StandardCompressionOptions#deflate()}.
     */
    public HttpContentCompressor() {
        this(0, (CompressionOptions[]) null);
    }

    /**
     * Creates a new handler with the specified compression level, default
     * window size (<tt>15</tt>) and default memory level (<tt>8</tt>).
     *
     * @param compressionLevel
     *        {@code 1} yields the fastest compression and {@code 9} yields the
     *        best compression.  {@code 0} means no compression.  The default
     *        compression level is {@code 6}.
     */
    @Deprecated
    public HttpContentCompressor(int compressionLevel) {
        this(compressionLevel, 15, 8, 0);
    }

    /**
     * Creates a new handler with the specified compression level, window size,
     * and memory level.
     *
     * @param compressionLevel
     *        {@code 1} yields the fastest compression and {@code 9} yields the
     *        best compression.  {@code 0} means no compression.  The default
     *        compression level is {@code 6}.
     * @param windowBits
     *        The base two logarithm of the size of the history buffer.  The
     *        value should be in the range {@code 9} to {@code 15} inclusive.
     *        Larger values result in better compression at the expense of
     *        memory usage.  The default value is {@code 15}.
     * @param memLevel
     *        How much memory should be allocated for the internal compression
     *        state.  {@code 1} uses minimum memory and {@code 9} uses maximum
     *        memory.  Larger values result in better and faster compression
     *        at the expense of memory usage.  The default value is {@code 8}
     */
    @Deprecated
    public HttpContentCompressor(int compressionLevel, int windowBits, int memLevel) {
        this(compressionLevel, windowBits, memLevel, 0);
    }

    /**
     * Creates a new handler with the specified compression level, window size,
     * and memory level.
     *
     * @param compressionLevel
     *        {@code 1} yields the fastest compression and {@code 9} yields the
     *        best compression.  {@code 0} means no compression.  The default
     *        compression level is {@code 6}.