/*
 * Copyright (c) 2012, 2020 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package org.glassfish.grizzly.http.server.util;

import java.io.IOException;

import org.glassfish.grizzly.filterchain.BaseFilter;
import org.glassfish.grizzly.filterchain.FilterChainBuilder;
import org.glassfish.grizzly.filterchain.FilterChainContext;
import org.glassfish.grizzly.filterchain.NextAction;
import org.glassfish.grizzly.http.HttpContent;
import org.glassfish.grizzly.http.server.AddOn;
import org.glassfish.grizzly.http.server.HttpServerFilter;
import org.glassfish.grizzly.http.server.NetworkListener;

AggregatorAddOn installs AggregatorFilter into HttpServer FilterChain. AggregatorFilter is responsible for aggregating input HTTP message payload (either request or response) and pass it to the next filter in chain only when entire HTTP message (including payload) is read. 
Author:
Alexey Stashok/**
 * AggregatorAddOn installs {@link AggregatorFilter} into HttpServer FilterChain. {@link AggregatorFilter} is
 * responsible for aggregating input HTTP message payload (either request or response) and pass it to the next filter in
 * chain only when entire HTTP message (including payload) is read.
 *
 * @author Alexey Stashok
 */
public class AggregatorAddOn implements AddOn {

    
{@inheritDoc}
/**
     * {@inheritDoc}
     */
    @Override
    public void setup(final NetworkListener networkListener, final FilterChainBuilder builder) {

        // Get the index of HttpServerFilter in the HttpServer filter chain
        final int httpServerFilterIdx = builder.indexOfType(HttpServerFilter.class);

        if (httpServerFilterIdx >= 0) {
            // Insert the AggregatorFilter right before HttpServerFilter
            builder.add(httpServerFilterIdx, new AggregatorFilter());
        }
    }

    private static class AggregatorFilter extends BaseFilter {

        @Override
        public NextAction handleRead(final FilterChainContext ctx) throws IOException {
            final Object message = ctx.getMessage();

            // If the input message is not HttpContent or it's last HttpContent message -
            // pass the message to a next filter
            if (!(message instanceof HttpContent) || ((HttpContent) message).isLast()) {
                return ctx.getInvokeAction();
            }

            // if it's HttpContent chunk (not last) - save it and stop filter chain processing.
            return ctx.getStopAction(message);
        }
    }
}