/*
 * $HeadURL$
 * $Revision$
 * $Date$
 *
 * ====================================================================
 * 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */
package org.apache.http.examples.nio;

import java.io.File;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.InetSocketAddress;
import java.net.URLDecoder;
import java.util.Locale;

import org.apache.http.HttpEntity;
import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpException;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.MethodNotSupportedException;
import org.apache.http.impl.DefaultConnectionReuseStrategy;
import org.apache.http.impl.DefaultHttpResponseFactory;
import org.apache.http.impl.nio.DefaultServerIOEventDispatch;
import org.apache.http.impl.nio.reactor.DefaultListeningIOReactor;
import org.apache.http.nio.NHttpConnection;
import org.apache.http.nio.entity.NFileEntity;
import org.apache.http.nio.entity.NStringEntity;
import org.apache.http.nio.protocol.BufferingHttpServiceHandler;
import org.apache.http.nio.protocol.EventListener;
import org.apache.http.nio.reactor.IOEventDispatch;
import org.apache.http.nio.reactor.ListeningIOReactor;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.CoreConnectionPNames;
import org.apache.http.params.CoreProtocolPNames;
import org.apache.http.params.HttpParams;
import org.apache.http.protocol.BasicHttpProcessor;
import org.apache.http.protocol.HttpContext;
import org.apache.http.protocol.HttpRequestHandler;
import org.apache.http.protocol.HttpRequestHandlerRegistry;
import org.apache.http.protocol.ResponseConnControl;
import org.apache.http.protocol.ResponseContent;
import org.apache.http.protocol.ResponseDate;
import org.apache.http.protocol.ResponseServer;
import org.apache.http.util.EntityUtils;

/**
 * Basic, yet fully functional and spec compliant, HTTP/1.1 server based on the non-blocking 
 * I/O model.
 * <p>
 * Please note the purpose of this application is demonstrate the usage of HttpCore APIs.
 * It is NOT intended to demonstrate the most efficient way of building an HTTP server. 
 * 
 *
 * @version $Revision$
 */
public class NHttpServer {

    public static void main(String[] args) throws Exception {
        if (args.length < 1) {
            System.err.println("Please specify document root directory");
            System.exit(1);
        }
        HttpParams params = new BasicHttpParams();
        params
            .setIntParameter(CoreConnectionPNames.SO_TIMEOUT, 5000)
            .setIntParameter(CoreConnectionPNames.SOCKET_BUFFER_SIZE, 8 * 1024)
            .setBooleanParameter(CoreConnectionPNames.STALE_CONNECTION_CHECK, false)
            .setBooleanParameter(CoreConnectionPNames.TCP_NODELAY, true)
            .setParameter(CoreProtocolPNames.ORIGIN_SERVER, "HttpComponents/1.1");

        BasicHttpProcessor httpproc = new BasicHttpProcessor();
        httpproc.addInterceptor(new ResponseDate());
        httpproc.addInterceptor(new ResponseServer());
        httpproc.addInterceptor(new ResponseContent());
        httpproc.addInterceptor(new ResponseConnControl());

        BufferingHttpServiceHandler handler = new BufferingHttpServiceHandler(
                httpproc,
                new DefaultHttpResponseFactory(),
                new DefaultConnectionReuseStrategy(),
                params);

        // Set up request handlers
        HttpRequestHandlerRegistry reqistry = new HttpRequestHandlerRegistry();
        reqistry.register("*", new HttpFileHandler(args[0]));

        handler.setHandlerResolver(reqistry);

        // Provide an event logger
        handler.setEventListener(new EventLogger());

        IOEventDispatch ioEventDispatch = new DefaultServerIOEventDispatch(handler, params);
        ListeningIOReactor ioReactor = new DefaultListeningIOReactor(2, params);
        try {
            ioReactor.listen(new InetSocketAddress(8080));
            ioReactor.execute(ioEventDispatch);
        } catch (InterruptedIOException ex) {
            System.err.println("Interrupted");
        } catch (IOException e) {
            System.err.println("I/O error: " + e.getMessage());
        }
        System.out.println("Shutdown");
    }

    static class HttpFileHandler implements HttpRequestHandler  {

        private final String docRoot;

        public HttpFileHandler(final String docRoot) {
            super();
            this.docRoot = docRoot;
        }

        public void handle(
                final HttpRequest request,
                final HttpResponse response,
                final HttpContext context) throws HttpException, IOException {

            String method = request.getRequestLine().getMethod().toUpperCase(Locale.ENGLISH);
            if (!method.equals("GET") && !method.equals("HEAD") && !method.equals("POST")) {
                throw new MethodNotSupportedException(method + " method not supported");
            }

            if (request instanceof HttpEntityEnclosingRequest) {
                HttpEntity entity = ((HttpEntityEnclosingRequest) request).getEntity();
                byte[] entityContent = EntityUtils.toByteArray(entity);
                System.out.println("Incoming entity content (bytes): " + entityContent.length);
            }

            String target = request.getRequestLine().getUri();
            final File file = new File(this.docRoot, URLDecoder.decode(target, "UTF-8"));
            if (!file.exists()) {

                response.setStatusCode(HttpStatus.SC_NOT_FOUND);
                NStringEntity entity = new NStringEntity(
                        "<html><body><h1>File" + file.getPath() +
                        " not found</h1></body></html>", "UTF-8");
                entity.setContentType("text/html; charset=UTF-8");
                response.setEntity(entity);
                System.out.println("File " + file.getPath() + " not found");

            } else if (!file.canRead() || file.isDirectory()) {

                response.setStatusCode(HttpStatus.SC_FORBIDDEN);
                NStringEntity entity = new NStringEntity(
                        "<html><body><h1>Access denied</h1></body></html>",
                        "UTF-8");
                entity.setContentType("text/html; charset=UTF-8");
                response.setEntity(entity);
                System.out.println("Cannot read file " + file.getPath());

            } else {

                response.setStatusCode(HttpStatus.SC_OK);
                NFileEntity body = new NFileEntity(file, "text/html");
                response.setEntity(body);
                System.out.println("Serving file " + file.getPath());

            }
        }

    }

    static class EventLogger implements EventListener {

        public void connectionOpen(final NHttpConnection conn) {
            System.out.println("Connection open: " + conn);
        }

        public void connectionTimeout(final NHttpConnection conn) {
            System.out.println("Connection timed out: " + conn);
        }

        public void connectionClosed(final NHttpConnection conn) {
            System.out.println("Connection closed: " + conn);
        }

        public void fatalIOException(final IOException ex, final NHttpConnection conn) {
            System.err.println("I/O error: " + ex.getMessage());
        }

        public void fatalProtocolException(final HttpException ex, final NHttpConnection conn) {
            System.err.println("HTTP error: " + ex.getMessage());
        }

    }

}