/*
 * ====================================================================
 * 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.client;

import org.apache.http.Consts;
import org.apache.http.Header;
import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.ParseException;
import org.apache.http.client.CookieStore;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.client.config.AuthSchemes;
import org.apache.http.client.config.CookieSpecs;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.protocol.HttpClientContext;
import org.apache.http.config.ConnectionConfig;
import org.apache.http.config.MessageConstraints;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.DnsResolver;
import org.apache.http.conn.routing.HttpRoute;
import org.apache.http.conn.ssl.BrowserCompatHostnameVerifier;
import org.apache.http.conn.ssl.SSLContexts;
import org.apache.http.conn.ssl.X509HostnameVerifier;
import org.apache.http.impl.DefaultHttpResponseFactory;
import org.apache.http.impl.client.BasicCookieStore;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.conn.SystemDefaultDnsResolver;
import org.apache.http.impl.nio.client.CloseableHttpAsyncClient;
import org.apache.http.impl.nio.client.HttpAsyncClients;
import org.apache.http.impl.nio.codecs.DefaultHttpRequestWriterFactory;
import org.apache.http.impl.nio.codecs.DefaultHttpResponseParser;
import org.apache.http.impl.nio.codecs.DefaultHttpResponseParserFactory;
import org.apache.http.impl.nio.conn.ManagedNHttpClientConnectionFactory;
import org.apache.http.impl.nio.conn.PoolingNHttpClientConnectionManager;
import org.apache.http.impl.nio.reactor.DefaultConnectingIOReactor;
import org.apache.http.impl.nio.reactor.IOReactorConfig;
import org.apache.http.message.BasicHeader;
import org.apache.http.message.BasicLineParser;
import org.apache.http.message.LineParser;
import org.apache.http.nio.NHttpMessageParser;
import org.apache.http.nio.NHttpMessageParserFactory;
import org.apache.http.nio.NHttpMessageWriterFactory;
import org.apache.http.nio.conn.ManagedNHttpClientConnection;
import org.apache.http.nio.conn.NHttpConnectionFactory;
import org.apache.http.nio.conn.NoopIOSessionStrategy;
import org.apache.http.nio.conn.SchemeIOSessionStrategy;
import org.apache.http.nio.conn.ssl.SSLIOSessionStrategy;
import org.apache.http.nio.reactor.ConnectingIOReactor;
import org.apache.http.nio.reactor.SessionInputBuffer;
import org.apache.http.nio.util.HeapByteBufferAllocator;
import org.apache.http.util.CharArrayBuffer;

import javax.net.ssl.SSLContext;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.nio.charset.CodingErrorAction;
import java.util.Arrays;
import java.util.concurrent.Future;

/**
 * This example demonstrates how to customize and configure the most common aspects
 * of HTTP request execution and connection management.
 */
public class AsyncClientConfiguration {

    public final static void main(String[] args) throws Exception {

        // Use custom message parser / writer to customize the way HTTP
        // messages are parsed from and written out to the data stream.
        NHttpMessageParserFactory<HttpResponse> responseParserFactory = new DefaultHttpResponseParserFactory() {

            @Override
            public NHttpMessageParser<HttpResponse> create(
                    final SessionInputBuffer buffer,
                    final MessageConstraints constraints) {
                LineParser lineParser = new BasicLineParser() {

                    @Override
                    public Header parseHeader(final CharArrayBuffer buffer) {
                        try {
                            return super.parseHeader(buffer);
                        } catch (ParseException ex) {
                            return new BasicHeader(buffer.toString(), null);
                        }
                    }

                };
                return new DefaultHttpResponseParser(
                        buffer, lineParser, DefaultHttpResponseFactory.INSTANCE, constraints);
            }

        };
        NHttpMessageWriterFactory<HttpRequest> requestWriterFactory = new DefaultHttpRequestWriterFactory();

        // Use a custom connection factory to customize the process of
        // initialization of outgoing HTTP connections. Beside standard connection
        // configuration parameters HTTP connection factory can define message
        // parser / writer routines to be employed by individual connections.
        NHttpConnectionFactory<ManagedNHttpClientConnection> connFactory = new ManagedNHttpClientConnectionFactory(
                requestWriterFactory, responseParserFactory, HeapByteBufferAllocator.INSTANCE);

        // Client HTTP connection objects when fully initialized can be bound to
        // an arbitrary network socket. The process of network socket initialization,
        // its connection to a remote address and binding to a local one is controlled
        // by a connection socket factory.

        // SSL context for secure connections can be created either based on
        // system or application specific properties.
        SSLContext sslcontext = SSLContexts.createSystemDefault();
        // Use custom hostname verifier to customize SSL hostname verification.
        X509HostnameVerifier hostnameVerifier = new BrowserCompatHostnameVerifier();

        // Create a registry of custom connection session strategies for supported
        // protocol schemes.
        Registry<SchemeIOSessionStrategy> sessionStrategyRegistry = RegistryBuilder.<SchemeIOSessionStrategy>create()
            .register("http", NoopIOSessionStrategy.INSTANCE)
            .register("https", new SSLIOSessionStrategy(sslcontext, hostnameVerifier))
            .build();

        // Use custom DNS resolver to override the system DNS resolution.
        DnsResolver dnsResolver = new SystemDefaultDnsResolver() {

            @Override
            public InetAddress[] resolve(final String host) throws UnknownHostException {
                if (host.equalsIgnoreCase("myhost")) {
                    return new InetAddress[] { InetAddress.getByAddress(new byte[] {127, 0, 0, 1}) };
                } else {
                    return super.resolve(host);
                }
            }

        };

        // Create I/O reactor configuration
        IOReactorConfig ioReactorConfig = IOReactorConfig.custom()
                .setIoThreadCount(Runtime.getRuntime().availableProcessors())
                .setConnectTimeout(30000)
                .setSoTimeout(30000)
                .build();

        // Create a custom I/O reactort
        ConnectingIOReactor ioReactor = new DefaultConnectingIOReactor(ioReactorConfig);

        // Create a connection manager with custom configuration.
        PoolingNHttpClientConnectionManager connManager = new PoolingNHttpClientConnectionManager(
                ioReactor, connFactory, sessionStrategyRegistry, dnsResolver);

        // Create message constraints
        MessageConstraints messageConstraints = MessageConstraints.custom()
            .setMaxHeaderCount(200)
            .setMaxLineLength(2000)
            .build();
        // Create connection configuration
        ConnectionConfig connectionConfig = ConnectionConfig.custom()
            .setMalformedInputAction(CodingErrorAction.IGNORE)
            .setUnmappableInputAction(CodingErrorAction.IGNORE)
            .setCharset(Consts.UTF_8)
            .setMessageConstraints(messageConstraints)
            .build();
        // Configure the connection manager to use connection configuration either
        // by default or for a specific host.
        connManager.setDefaultConnectionConfig(connectionConfig);
        connManager.setConnectionConfig(new HttpHost("somehost", 80), ConnectionConfig.DEFAULT);

        // Configure total max or per route limits for persistent connections
        // that can be kept in the pool or leased by the connection manager.
        connManager.setMaxTotal(100);
        connManager.setDefaultMaxPerRoute(10);
        connManager.setMaxPerRoute(new HttpRoute(new HttpHost("somehost", 80)), 20);

        // Use custom cookie store if necessary.
        CookieStore cookieStore = new BasicCookieStore();
        // Use custom credentials provider if necessary.
        CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
        // Create global request configuration
        RequestConfig defaultRequestConfig = RequestConfig.custom()
            .setCookieSpec(CookieSpecs.BEST_MATCH)
            .setExpectContinueEnabled(true)
            .setStaleConnectionCheckEnabled(true)
            .setTargetPreferredAuthSchemes(Arrays.asList(AuthSchemes.NTLM, AuthSchemes.DIGEST))
            .setProxyPreferredAuthSchemes(Arrays.asList(AuthSchemes.BASIC))
            .build();

        // Create an HttpClient with the given custom dependencies and configuration.
        CloseableHttpAsyncClient httpclient = HttpAsyncClients.custom()
            .setConnectionManager(connManager)
            .setDefaultCookieStore(cookieStore)
            .setDefaultCredentialsProvider(credentialsProvider)
            .setProxy(new HttpHost("myproxy", 8080))
            .setDefaultRequestConfig(defaultRequestConfig)
            .build();

        try {
            HttpGet httpget = new HttpGet("http://localhost/");
            // Request configuration can be overridden at the request level.
            // They will take precedence over the one set at the client level.
            RequestConfig requestConfig = RequestConfig.copy(defaultRequestConfig)
                .setSocketTimeout(5000)
                .setConnectTimeout(5000)
                .setConnectionRequestTimeout(5000)
                .setProxy(new HttpHost("myotherproxy", 8080))
                .build();
            httpget.setConfig(requestConfig);

            // Execution context can be customized locally.
            HttpClientContext localContext = HttpClientContext.create();
            // Contextual attributes set the local context level will take
            // precedence over those set at the client level.
            localContext.setCookieStore(cookieStore);
            localContext.setCredentialsProvider(credentialsProvider);

            System.out.println("Executing request " + httpget.getRequestLine());

            httpclient.start();

            // Pass local context as a parameter
            Future<HttpResponse> future = httpclient.execute(httpget, localContext, null);

            // Please note that it may be unsafe to access HttpContext instance
            // while the request is still being executed

            HttpResponse response = future.get();
            System.out.println("Response: " + response.getStatusLine());

            // Once the request has been executed the local context can
            // be used to examine updated state and various objects affected
            // by the request execution.

            // Last executed request
            localContext.getRequest();
            // Execution route
            localContext.getHttpRoute();
            // Target auth state
            localContext.getTargetAuthState();
            // Proxy auth state
            localContext.getTargetAuthState();
            // Cookie origin
            localContext.getCookieOrigin();
            // Cookie spec used
            localContext.getCookieSpec();
            // User security token
            localContext.getUserToken();
        } finally {
            httpclient.close();
        }
    }

}