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Java example source code file (Socks5PasswordAuthRequestDecoder.java)

This example Java source code file (Socks5PasswordAuthRequestDecoder.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

bytebuf, decoderexception, defaultsocks5passwordauthrequest, failure, init, list, override, replayingdecoder, socks5message, socks5passwordauthrequestdecoder, state, success, throwable, util

The Socks5PasswordAuthRequestDecoder.java Java example source code

/*
 * Copyright 2014 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.socksx.v5;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.DecoderException;
import io.netty.handler.codec.DecoderResult;
import io.netty.handler.codec.ReplayingDecoder;
import io.netty.handler.codec.socksx.v5.Socks5PasswordAuthRequestDecoder.State;
import io.netty.util.CharsetUtil;

import java.util.List;

/**
 * Decodes a single {@link Socks5PasswordAuthRequest} from the inbound {@link ByteBuf}s.
 * On successful decode, this decoder will forward the received data to the next handler, so that
 * other handler can remove or replace this decoder later.  On failed decode, this decoder will
 * discard the received data, so that other handler closes the connection later.
 */
public class Socks5PasswordAuthRequestDecoder extends ReplayingDecoder<State> {

    enum State {
        INIT,
        SUCCESS,
        FAILURE
    }

    public Socks5PasswordAuthRequestDecoder() {
        super(State.INIT);
    }

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
        try {
            switch (state()) {
            case INIT: {
                final int startOffset = in.readerIndex();
                final byte version = in.getByte(startOffset);
                if (version != 1) {
                    throw new DecoderException("unsupported subnegotiation version: " + version + " (expected: 1)");
                }

                final int usernameLength = in.getUnsignedByte(startOffset + 1);
                final int passwordLength = in.getUnsignedByte(startOffset + 2 + usernameLength);
                final int totalLength = usernameLength + passwordLength + 3;

                in.skipBytes(totalLength);
                out.add(new DefaultSocks5PasswordAuthRequest(
                        in.toString(startOffset + 2, usernameLength, CharsetUtil.US_ASCII),
                        in.toString(startOffset + 3 + usernameLength, passwordLength, CharsetUtil.US_ASCII)));

                checkpoint(State.SUCCESS);
            }
            case SUCCESS: {
                int readableBytes = actualReadableBytes();
                if (readableBytes > 0) {
                    out.add(in.readRetainedSlice(readableBytes));
                }
                break;
            }
            case FAILURE: {
                in.skipBytes(actualReadableBytes());
                break;
            }
            }
        } catch (Exception e) {
            fail(out, e);
        }
    }

    private void fail(List<Object> out, Throwable cause) {
        if (!(cause instanceof DecoderException)) {
            cause = new DecoderException(cause);
        }

        checkpoint(State.FAILURE);

        Socks5Message m = new DefaultSocks5PasswordAuthRequest("", "");
        m.setDecoderResult(DecoderResult.failure(cause));
        out.add(m);
    }
}

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