netty5/codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketDecoderConfig.java

/*
 * Copyright 2019 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.handler.codec.http.websocketx;

import io.netty.util.internal.ObjectUtil;

/**
 * Frames decoder configuration.
 */
public final class WebSocketDecoderConfig {

    private final int maxFramePayloadLength;
    private final boolean expectMaskedFrames;
    private final boolean allowMaskMismatch;
    private final boolean allowExtensions;
    private final boolean closeOnProtocolViolation;

    /**
     * Constructor
     *
     * @param maxFramePayloadLength
     *            Maximum length of a frame's payload. Setting this to an appropriate value for you application
     *            helps check for denial of services attacks.
     * @param expectMaskedFrames
     *            Web socket servers must set this to true processed incoming masked payload. Client implementations
     *            must set this to false.
     * @param allowMaskMismatch
     *            Allows to loosen the masking requirement on received frames. When this is set to false then also
     *            frames which are not masked properly according to the standard will still be accepted.
     * @param allowExtensions
     *            Flag to allow reserved extension bits to be used or not
     * @param closeOnProtocolViolation
     *            Flag to send close frame immediately on any protocol violation.ion.
     */
    private WebSocketDecoderConfig(int maxFramePayloadLength, boolean expectMaskedFrames, boolean allowMaskMismatch,
                                  boolean allowExtensions, boolean closeOnProtocolViolation) {
        this.maxFramePayloadLength = maxFramePayloadLength;
        this.expectMaskedFrames = expectMaskedFrames;
        this.allowMaskMismatch = allowMaskMismatch;
        this.allowExtensions = allowExtensions;
        this.closeOnProtocolViolation = closeOnProtocolViolation;
    }

    public int maxFramePayloadLength() {
        return maxFramePayloadLength;
    }

    public boolean expectMaskedFrames() {
        return expectMaskedFrames;
    }

    public boolean allowMaskMismatch() {
        return allowMaskMismatch;
    }

    public boolean allowExtensions() {
        return allowExtensions;
    }

    public boolean closeOnProtocolViolation() {
        return closeOnProtocolViolation;
    }

    @Override
    public String toString() {
        return "WebSocketDecoderConfig" +
            " [maxFramePayloadLength=" + maxFramePayloadLength +
            ", expectMaskedFrames=" + expectMaskedFrames +
            ", allowMaskMismatch=" + allowMaskMismatch +
            ", allowExtensions=" + allowExtensions +
            ", closeOnProtocolViolation=" + closeOnProtocolViolation +
            "]";
    }

    public Builder toBuilder() {
        return new Builder(this);
    }

    public static Builder newBuilder() {
        return new Builder();
    }

    public static final class Builder {
        private int maxFramePayloadLength = 65536;
        private boolean expectMaskedFrames = true;
        private boolean allowMaskMismatch;
        private boolean allowExtensions;
        private boolean closeOnProtocolViolation = true;

        private Builder() {
            /* No-op */
        }

        private Builder(WebSocketDecoderConfig decoderConfig) {
            ObjectUtil.checkNotNull(decoderConfig, "decoderConfig");
            maxFramePayloadLength = decoderConfig.maxFramePayloadLength();
            expectMaskedFrames = decoderConfig.expectMaskedFrames();
            allowMaskMismatch = decoderConfig.allowMaskMismatch();
            allowExtensions = decoderConfig.allowExtensions();
            closeOnProtocolViolation = decoderConfig.closeOnProtocolViolation();
        }

        public Builder maxFramePayloadLength(int maxFramePayloadLength) {
            this.maxFramePayloadLength = maxFramePayloadLength;
            return this;
        }

        public Builder expectMaskedFrames(boolean expectMaskedFrames) {
            this.expectMaskedFrames = expectMaskedFrames;
            return this;
        }

        public Builder allowMaskMismatch(boolean allowMaskMismatch) {
            this.allowMaskMismatch = allowMaskMismatch;
            return this;
        }

        public Builder allowExtensions(boolean allowExtensions) {
            this.allowExtensions = allowExtensions;
            return this;
        }

        public Builder closeOnProtocolViolation(boolean closeOnProtocolViolation) {
            this.closeOnProtocolViolation = closeOnProtocolViolation;
            return this;
        }

        public WebSocketDecoderConfig build() {
            return new WebSocketDecoderConfig(
                maxFramePayloadLength, expectMaskedFrames, allowMaskMismatch,
                allowExtensions, closeOnProtocolViolation);
        }
    }
}