jj.http.server.HttpRequestListeningHandler.java Source code

Introduction

Here is the source code for jj.http.server.HttpRequestListeningHandler.java

Source

/*
 *    Copyright 2012 Jason Miller
 *
 * Licensed 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 jj.http.server;

import static jj.http.server.DefaultResponse.*;

import java.util.Map;
import java.util.Map.Entry;

import javax.inject.Inject;

import jj.event.Publisher;
import jj.http.server.methods.HttpMethodHandler;

import com.google.inject.Provider;

import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.HttpMethod;
import io.netty.handler.codec.http.HttpRequest;

/**
 * first-chance disposition of an incoming request
 * 
 * basics flow is
 * 
 * - check for decoder errors
 * 
 * - check if the method is one of the methods we are
 *   prepared to handle.  this is determined by having
 *   a registered handler
 * 
 * - add that handler to the pipeline and fire upstream
 * 
 * @author jason
 *
 */
class HttpRequestListeningHandler extends SimpleChannelInboundHandler<HttpRequest> {

    private final Publisher publisher;

    private final Map<HttpMethod, Provider<HttpMethodHandler>> methodHandlers;

    private String name;

    private HttpRequest request;

    @Inject
    HttpRequestListeningHandler(final Publisher publisher,
            final Map<HttpMethod, Provider<HttpMethodHandler>> methodHandlers) {
        this.publisher = publisher;
        this.methodHandlers = methodHandlers;
    }

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, HttpRequest request) throws Exception {
        this.request = request;

        if (request.getDecoderResult().isFailure()) {
            // respond with BAD_REQUEST and close the connection
            // (unless we are being proxied and the connection is keep-alive, that is)
            BAD_REQUEST.writeAndFlush(ctx).addListener(ChannelFutureListener.CLOSE);

        } else if (methodHandlers.containsKey(request.getMethod())) {

            HttpMethodHandler methodHandler = methodHandlers.get(request.getMethod()).get();
            methodHandler.request(request);

            ChannelPipeline p = ctx.pipeline();
            p.addAfter(name, "method handler", methodHandler);

            ctx.fireChannelRead(request);

        } else {
            // respond with NOT_IMPLEMENTED
            // unless we are being proxied and the connection is keep-alive
            NOT_IMPLEMENTED.writeAndFlush(ctx).addListener(ChannelFutureListener.CLOSE);
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        publisher.publish(new RequestErrored(request, cause));
        INTERNAL_SERVER_ERROR.writeAndFlush(ctx).addListener(ChannelFutureListener.CLOSE);
    }

    @Override
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        for (Entry<String, ChannelHandler> entry : ctx.pipeline()) {
            if (entry.getValue() == this) {
                name = entry.getKey();
            }
        }
        assert name != null : "couldn't find myself in the pipeline!";
    }

}