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Java example source code file (HttpToHttp2ConnectionHandler.java)

This example Java source code file (HttpToHttp2ConnectionHandler.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

exception, fullhttpmessage, http2connectionencoder, http2headers, http2settings, httpcontent, httpmessage, httptohttp2connectionhandler, lasthttpcontent, object, override, simplechannelpromiseaggregator, throwable, unstableapi

The HttpToHttp2ConnectionHandler.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.http2;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.handler.codec.http.FullHttpMessage;
import io.netty.handler.codec.http.HttpContent;
import io.netty.handler.codec.http.HttpHeaders;
import io.netty.handler.codec.http.HttpMessage;
import io.netty.handler.codec.http.LastHttpContent;
import io.netty.handler.codec.http2.Http2CodecUtil.SimpleChannelPromiseAggregator;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.internal.UnstableApi;

/**
 * Translates HTTP/1.x object writes into HTTP/2 frames.
 * <p>
 * See {@link InboundHttp2ToHttpAdapter} to get translation from HTTP/2 frames to HTTP/1.x objects.
 */
@UnstableApi
public class HttpToHttp2ConnectionHandler extends Http2ConnectionHandler {

    private final boolean validateHeaders;
    private int currentStreamId;

    protected HttpToHttp2ConnectionHandler(Http2ConnectionDecoder decoder, Http2ConnectionEncoder encoder,
                                           Http2Settings initialSettings, boolean validateHeaders) {
        super(decoder, encoder, initialSettings);
        this.validateHeaders = validateHeaders;
    }

    /**
     * Get the next stream id either from the {@link HttpHeaders} object or HTTP/2 codec
     *
     * @param httpHeaders The HTTP/1.x headers object to look for the stream id
     * @return The stream id to use with this {@link HttpHeaders} object
     * @throws Exception If the {@code httpHeaders} object specifies an invalid stream id
     */
    private int getStreamId(HttpHeaders httpHeaders) throws Exception {
        return httpHeaders.getInt(HttpConversionUtil.ExtensionHeaderNames.STREAM_ID.text(),
                                  connection().local().incrementAndGetNextStreamId());
    }

    /**
     * Handles conversion of {@link HttpMessage} and {@link HttpContent} to HTTP/2 frames.
     */
    @Override
    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) {

        if (!(msg instanceof HttpMessage || msg instanceof HttpContent)) {
            ctx.write(msg, promise);
            return;
        }

        boolean release = true;
        SimpleChannelPromiseAggregator promiseAggregator =
                new SimpleChannelPromiseAggregator(promise, ctx.channel(), ctx.executor());
        try {
            Http2ConnectionEncoder encoder = encoder();
            boolean endStream = false;
            if (msg instanceof HttpMessage) {
                final HttpMessage httpMsg = (HttpMessage) msg;

                // Provide the user the opportunity to specify the streamId
                currentStreamId = getStreamId(httpMsg.headers());

                // Convert and write the headers.
                Http2Headers http2Headers = HttpConversionUtil.toHttp2Headers(httpMsg, validateHeaders);
                endStream = msg instanceof FullHttpMessage && !((FullHttpMessage) msg).content().isReadable();
                encoder.writeHeaders(ctx, currentStreamId, http2Headers, 0, endStream, promiseAggregator.newPromise());
            }

            if (!endStream && msg instanceof HttpContent) {
                boolean isLastContent = false;
                Http2Headers trailers = EmptyHttp2Headers.INSTANCE;
                if (msg instanceof LastHttpContent) {
                    isLastContent = true;

                    // Convert any trailing headers.
                    final LastHttpContent lastContent = (LastHttpContent) msg;
                    trailers = HttpConversionUtil.toHttp2Headers(lastContent.trailingHeaders(), validateHeaders);
                }

                // Write the data
                final ByteBuf content = ((HttpContent) msg).content();
                endStream = isLastContent && trailers.isEmpty();
                release = false;
                encoder.writeData(ctx, currentStreamId, content, 0, endStream, promiseAggregator.newPromise());

                if (!trailers.isEmpty()) {
                    // Write trailing headers.
                    encoder.writeHeaders(ctx, currentStreamId, trailers, 0, true, promiseAggregator.newPromise());
                }
            }
        } catch (Throwable t) {
            promiseAggregator.setFailure(t);
        } finally {
            if (release) {
                ReferenceCountUtil.release(msg);
            }
            promiseAggregator.doneAllocatingPromises();
        }
    }
}

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