org.apache.tajo.storage.http.ExampleHttpServerHandler.java Source code

Introduction

Here is the source code for org.apache.tajo.storage.http.ExampleHttpServerHandler.java

Source

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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 org.apache.tajo.storage.http;

import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.handler.codec.http.*;
import io.netty.handler.codec.http.HttpHeaders.Names;
import io.netty.util.CharsetUtil;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import javax.activation.MimetypesFileTypeMap;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;

import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_TYPE;
import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST;
import static io.netty.handler.codec.http.HttpResponseStatus.OK;
import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;

public class ExampleHttpServerHandler extends SimpleChannelInboundHandler<FullHttpRequest> {

    private static final Log LOG = LogFactory.getLog(ExampleHttpServerHandler.class);

    @Override
    protected void channelRead0(ChannelHandlerContext context, FullHttpRequest request) throws Exception {

        if (request.getMethod().equals(HttpMethod.HEAD)) {

            processHead(context, request);

        } else if (request.getMethod().equals(HttpMethod.GET)) {

            processGet(context, request);

        } else {
            // error
            String msg = "Not supported method: " + request.getMethod();
            LOG.error(msg);
            context.writeAndFlush(getBadRequest(msg));
        }
    }

    private void processHead(ChannelHandlerContext context, FullHttpRequest request) {
        HttpHeaders headers = request.headers();
        FullHttpResponse response = null;

        if (headers.contains(Names.CONTENT_LENGTH)) {

            try {
                File file = getRequestedFile(request.getUri());

                response = new DefaultFullHttpResponse(HTTP_1_1,
                        request.getDecoderResult().isSuccess() ? OK : BAD_REQUEST);

                HttpHeaders.setContentLength(response, file.length());

            } catch (FileNotFoundException | URISyntaxException e) {
                response = getBadRequest(e.getMessage());
            }
        }

        context.writeAndFlush(response);
    }

    private void processGet(ChannelHandlerContext context, FullHttpRequest request) {
        try {
            File file = getRequestedFile(request.getUri());

            RandomAccessFile raf = new RandomAccessFile(file, "r");
            long fileLength = raf.length();

            HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK);
            HttpHeaders.setContentLength(response, fileLength);
            setContentTypeHeader(response, file);

            context.write(response);

            context.write(new DefaultFileRegion(raf.getChannel(), 0, fileLength));

            // Write the end marker.
            ChannelFuture future = context.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);
            future.addListener(ChannelFutureListener.CLOSE);

        } catch (IOException | URISyntaxException e) {
            context.writeAndFlush(getBadRequest(e.getMessage()));
        }
    }

    private static File getRequestedFile(String uri) throws FileNotFoundException, URISyntaxException {
        String path = URI.create(uri).getPath();
        URL url = ClassLoader.getSystemResource("dataset/" + path);

        if (url == null) {
            throw new FileNotFoundException(uri);
        }
        return new File(url.toURI());
    }

    private static FullHttpResponse getBadRequest(String message) {
        return new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST,
                Unpooled.copiedBuffer(message, CharsetUtil.UTF_8));
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext context, Throwable cause) {
        LOG.error(cause.getMessage(), cause);
        if (context.channel().isOpen()) {
            context.channel().close();
        }
    }

    /**
     * Sets the content type header for the HTTP Response
     * @param response HTTP response
     * @param file file to extract content type
     */
    private static void setContentTypeHeader(HttpResponse response, File file) {
        MimetypesFileTypeMap mimeTypesMap = new MimetypesFileTypeMap();
        response.headers().set(CONTENT_TYPE, mimeTypesMap.getContentType(file.getPath()));
    }
}