using HtmlAgilityPack;
using Nito.AsyncEx;
using System;
using System.Diagnostics;
using System.IO;
using System.IO.Compression;
using System.Net;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace test1
{
    class Program
    {
        static void Main(string[] args)
        {
            
 
var uri = new Uri("https://www.baidu.com/");
            string pageHtml=AsyncContext.Run(() => GetHttpDomByUrl(uri));
            HtmlDocument thisnode = new HtmlDocument();
            thisnode.LoadHtml(pageHtml);
            var tnode = thisnode.DocumentNode;
            if (tnode.SelectSingleNode("
 
//*/a[@name=\"tj_login\"]") != null)
            {
                Console.WriteLine("獲取到的資料為:"+tnode.SelectSingleNode("//*/a[@name=\"tj_login\"]").Attributes["href"].Value);
            }
            Console.WriteLine("測試成功");
            Console.ReadKey();
        }
        public static CookieContainer CookiesContainer = new
 
 CookieContainer();//定義Cookie容器
        static CookieContainer cookie = new CookieContainer();//設定為全域性，這樣可以方便每個函式直接呼叫
        public static async Task<string> GetHttpDomByUrl(Uri uri, string proxy = null)
        {
            Thread.Sleep(1000);
            return await Task.Run(() =>
            {
                var pageSource = string.Empty;
                try
                {
                    //模擬瀏覽器請求
                    //if (this.OnStart != null) this.OnStart(this, new OnStartEventArgs(uri));
                    var watch = new Stopwatch();
                    watch.Start();
                    var request = (HttpWebRequest)WebRequest.Create(uri);
                    request.Accept = "*/*";
                    request.ServicePoint.Expect100Continue = false;//加快載入速度
                    request.ServicePoint.UseNagleAlgorithm = false;//禁止Nagle演算法加快載入速度
                    request.AllowWriteStreamBuffering = false;//禁止緩衝加快載入速度
                    request.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip,deflate");//定義gzip壓縮頁面支援
                    request.ContentType = "application/x-www-form-urlencoded";//定義文件型別及編碼
                    request.AllowAutoRedirect = true;//禁止自動跳轉
                    //設定User-Agent，偽裝成Google Chrome瀏覽器
                    request.UserAgent = "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.102 Safari/537.36";
                    request.Timeout = 5000;//定義請求超時時間為5秒
                    request.KeepAlive = true;//啟用長連線
                    request.Method = "GET";//定義請求方式為GET     
                    request.CookieContainer = cookie;
                    if (proxy != null)
                    {
                        request.Proxy = new WebProxy(proxy);//設定代理伺服器IP，偽裝請求地址
                    }
                    //request.CookieContainer = this.CookiesContainer;//附加Cookie容器
                    request.ServicePoint.ConnectionLimit = int.MaxValue;//定義最大連線數
                    using (var response = (HttpWebResponse)request.GetResponse())
                    {
                       
                        //獲取請求響應
                        foreach (Cookie cookie in response.Cookies)
                        {
                            CookiesContainer.Add(cookie);//將Cookie加入容器，儲存登入狀態
                            
                        }
                        //判斷網頁是否被gzip壓縮 
                        if (response.ContentEncoding.ToLower().Contains("gzip"))
                        {
                            //解壓
                            using (GZipStream stream = new GZipStream(response.GetResponseStream(), CompressionMode.Decompress))
                            {
                                using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))
                                {
                                    pageSource = reader.ReadToEnd();
                                }
                            }
                        }
                        //判斷網頁http頭中是否Content-Encoding:deflate
                        else if (response.ContentEncoding.ToLower().Contains("deflate"))
                        {
                            //解壓
                            using (DeflateStream stream = new DeflateStream(response.GetResponseStream(), CompressionMode.Decompress))
                            {
                                using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))
                                {
                                    pageSource = reader.ReadToEnd();
                                }

                            }
                        }
                        //正常流獲取網頁
                        else
                        {
                            using (Stream stream = response.GetResponseStream())//原始
                            {
                                using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))
                                {

                                    pageSource = reader.ReadToEnd();
                                }
                            }
                        }
                    }
                    request.Abort();
                    watch.Stop();
                    var threadId = System.Threading.Thread.CurrentThread.ManagedThreadId;//獲取當前任務執行緒ID
                    var milliseconds = watch.ElapsedMilliseconds;//獲取請求執行時間
                    //if (this.OnCompleted != null)
                    //{
                    //    this.OnCompleted(this, new OnCompletedEventArgs(uri, threadId, milliseconds, pageSource));
                    //    // Console.WriteLine("程式執行完成");
                    //}
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"hello, task的執行緒ID為{Thread.CurrentThread.ManagedThreadId}");
                    Console.WriteLine(uri + $"請求頁面失敗正在重新請求,當前執行緒{Thread.CurrentThread.ManagedThreadId}:" + ex.Message.ToString());
                    Thread.Sleep(1000);
                    return AsyncContext.Run(() => GetHttpDomByUrl(uri));
                }
                return pageSource;
            });
        }
    }
}