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    • org.xbib.helianthus.internal.http.Http1ClientCodec Maven / Gradle / Ivy

    package org.xbib.helianthus.internal.http;

import io.netty.buffer.ByteBuf;
import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.CombinedChannelDuplexHandler;
import io.netty.handler.codec.PrematureChannelClosureException;
import io.netty.handler.codec.http.HttpClientUpgradeHandler;
import io.netty.handler.codec.http.HttpMessage;
import io.netty.handler.codec.http.HttpMethod;
import io.netty.handler.codec.http.HttpRequest;
import io.netty.handler.codec.http.HttpRequestEncoder;
import io.netty.handler.codec.http.HttpResponse;
import io.netty.handler.codec.http.HttpResponseDecoder;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.codec.http.LastHttpContent;
import io.netty.util.ReferenceCountUtil;

import java.util.ArrayDeque;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.atomic.AtomicLong;

/**
 * A combination of {@link HttpRequestEncoder} and {@link HttpResponseDecoder}
 * which enables easier client side HTTP implementation. {@link Http1ClientCodec}
 * provides additional state management for HEAD and CONNECT
 * requests, which {@link HttpResponseDecoder} lacks.  Please refer to
 * {@link HttpResponseDecoder} to learn what additional state management needs
 * to be done for HEAD and CONNECT and why
 * {@link HttpResponseDecoder} can not handle it by itself.
 *
 * If the {@link Channel} is closed and there are missing responses,
 * a {@link PrematureChannelClosureException} is thrown.
 *
 * @see HttpServerCodec
 */
public class Http1ClientCodec extends CombinedChannelDuplexHandler
        implements HttpClientUpgradeHandler.SourceCodec {

    /**
     * A queue that is used for correlating a request and a response.
     */
    private final Queue queue = new ArrayDeque<>();

    private final AtomicLong requestResponseCounter = new AtomicLong();

    private final boolean failOnMissingResponse;

    /**
     * If true, decoding stops (i.e. pass-through)
     */
    private boolean done;

    /**
     * Creates a new instance with the default decoder options
     * ({@code maxInitialLineLength (4096}}, {@code maxHeaderSize (8192)}, and
     * {@code maxChunkSize (8192)}).
     */
    public Http1ClientCodec() {
        this(4096, 8192, 8192, false);
    }

    /**
     * Creates a new instance with the specified decoder options.
     */
    public Http1ClientCodec(int maxInitialLineLength, int maxHeaderSize, int maxChunkSize) {
        this(maxInitialLineLength, maxHeaderSize, maxChunkSize, false);
    }

    /**
     * Creates a new instance with the specified decoder options.
     */
    public Http1ClientCodec(
            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize, boolean failOnMissingResponse) {
        this(maxInitialLineLength, maxHeaderSize, maxChunkSize, failOnMissingResponse, true);
    }

    /**
     * Creates a new instance with the specified decoder options.
     */
    public Http1ClientCodec(
            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize, boolean failOnMissingResponse,
            boolean validateHeaders) {
        init(new Decoder(maxInitialLineLength, maxHeaderSize, maxChunkSize, validateHeaders), new Encoder());
        this.failOnMissingResponse = failOnMissingResponse;
    }

    @Override
    public void prepareUpgradeFrom(ChannelHandlerContext ctx) {
        ((Encoder) outboundHandler()).upgraded = true;
    }

    /**
     * Upgrades to another protocol from HTTP. Removes the {@link Decoder} and {@link Encoder} from
     * the pipeline.
     */
    @Override
    public void upgradeFrom(ChannelHandlerContext ctx) {
        final ChannelPipeline p = ctx.pipeline();
        p.remove(this);
    }

    public boolean isSingleDecode() {
        return inboundHandler().isSingleDecode();
    }

    public void setSingleDecode(boolean singleDecode) {
        inboundHandler().setSingleDecode(singleDecode);
    }

    private final class Encoder extends HttpRequestEncoder {

        boolean upgraded;

        @Override
        protected void encode(ChannelHandlerContext ctx, Object msg, List out) throws Exception {
            if (upgraded) {
                out.add(ReferenceCountUtil.retain(msg));
                return;
            }
            if (msg instanceof HttpRequest && !done) {
                queue.offer(((HttpRequest) msg).method());
            }
            super.encode(ctx, msg, out);
            // check if the request is chunked if so do not increment
            if (failOnMissingResponse && msg instanceof LastHttpContent) {
                // increment as its the last chunk
                requestResponseCounter.incrementAndGet();
            }
        }
    }

    private final class Decoder extends HttpResponseDecoder {

        Decoder(int maxInitialLineLength, int maxHeaderSize, int maxChunkSize, boolean validateHeaders) {
            super(maxInitialLineLength, maxHeaderSize, maxChunkSize, validateHeaders);
        }

        @Override
        protected void decode(ChannelHandlerContext ctx, ByteBuf buffer, List out) throws Exception {
            if (done) {
                int readable = actualReadableBytes();
                if (readable == 0) {
                    // if non is readable just return null
                    // https://github.com/netty/netty/issues/1159
                    return;
                }
                out.add(buffer.readBytes(readable));
            } else {
                int oldSize = out.size();
                super.decode(ctx, buffer, out);
                if (failOnMissingResponse) {
                    int size = out.size();
                    for (int i = oldSize; i < size; i++) {
                        decrement(out.get(i));
                    }
                }
            }
        }

        private void decrement(Object msg) {
            if (msg == null) {
                return;
            }
            // check if it's an Header and its transfer encoding is not chunked.
            if (msg instanceof LastHttpContent) {
                requestResponseCounter.decrementAndGet();
            }
        }

        @Override
        protected boolean isContentAlwaysEmpty(HttpMessage msg) {
            final int statusCode = ((HttpResponse) msg).status().code();
            if (statusCode >= 100 && statusCode < 200) {
                // An informational response should be excluded from paired comparison.
                return true;
            }
            // Get the getMethod of the HTTP request that corresponds to the
            // current response.
            HttpMethod method = queue.poll();
            char firstChar = method.name().charAt(0);
            switch (firstChar) {
                case 'H':
                    // According to 4.3, RFC2616:
                    // All responses to the HEAD request getMethod MUST NOT include a
                    // message-body, even though the presence of entity-header fields
                    // might lead one to believe they do.
                    if (HttpMethod.HEAD.equals(method)) {
                        return true;

                        // The following code was inserted to work around the servers
                        // that behave incorrectly.  It has been commented out
                        // because it does not work with well behaving servers.
                        // Please note, even if the 'Transfer-Encoding: chunked'
                        // header exists in the HEAD response, the response should
                        // have absolutely no content.
                        //
                        //// Interesting edge case:
                        //// Some poorly implemented servers will send a zero-byte
                        //// chunk if Transfer-Encoding of the response is 'chunked'.
                        ////
                        //// return !msg.isChunked();
                    }
                    break;
                case 'C':
                    // Successful CONNECT request results in a response with empty body.
                    if (statusCode == 200 && HttpMethod.CONNECT.equals(method)) {
                        // Proxy connection established - Not HTTP anymore.
                        done = true;
                        queue.clear();
                        return true;
                    }
                    break;
                default:
                    break;
            }
            return super.isContentAlwaysEmpty(msg);
        }

        @Override
        public void channelInactive(ChannelHandlerContext ctx) throws Exception {
            super.channelInactive(ctx);
            if (failOnMissingResponse) {
                long missingResponses = requestResponseCounter.get();
                if (missingResponses > 0) {
                    ctx.fireExceptionCaught(new PrematureChannelClosureException("channel gone inactive with " +
                            missingResponses + " missing response(s)"));
                }
            }
        }
    }
}
    
    
    
    

    




    
    
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