标签: webclient

我使用WebClient从网站下载一个字符串(只包含纯文本,没有别的),所以我使用DownloadString方法:

WebClient wc = new WebClient();
string str = wc.DownloadString("http://blah");

它运行正常,但问题是它第一次下载字符串需要很长时间,比如5秒.之后它运作得很快.为什么会发生这种情况,如何解决这个问题呢？

我想从FTP服务器读取文件而不将其下载到本地文件.我写了一个函数,但它不起作用:

private string GetServerVersion()
{
    WebClient request = new WebClient();

    string url = FtpPath + FileName;
    string version = "";

    request.Credentials = new NetworkCredential(ftp_user, ftp_pas);

    try
    {
        byte[] newFileData = request.DownloadData(new Uri(FtpPath)+FileName);
        string fileString = System.Text.Encoding.UTF8.GetString(newFileData);
    }
    catch (WebException e)
    {
    }
    return version;
}

我目前有这个用于我的WebClient URL

WebClient Detail = new WebClient();
Detail.DownloadStringCompleted += new DownloadStringCompletedEventHandler(Detail_DownloadStringCompleted);
Detail.DownloadStringAsync(new Uri("http://api.trademe.co.nz/v1/Listings/" + ListingID.Text + ".xml"));

我想要做的是使用这个字符串:

void ListBoxSelectionChanged(object sender, SelectionChangedEventArgs args)
{
    var lbi = ((sender as ListBox).SelectedItem as TradeItem);
    if(lbi != null)
    {
        string id = lbi.ListingId.ToString();
    }
}

作为WbeClient URL的一部分.

例:

WebClient Detail = new WebClient();
Detail.DownloadStringCompleted += new DownloadStringCompletedEventHandler(Detail_DownloadStringCompleted);
Detail.DownloadStringAsync(new Uri("http://api.trademe.co.nz/v1/Listings/" + id + ".xml"));

无论如何在URL中使用此字符串如上所示？

完整代码#####################################

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media; …

我使用以下代码从互联网获取html数据:

WebProxy p = new WebProxy("localproxyIP:8080", true);
p.Credentials = new NetworkCredential("domain\\user", "password");
WebRequest.DefaultWebProxy = p;
WebClient client = new WebClient();
string downloadString = client.DownloadString("http://www.google.com");

但出现以下错误:"需要代理身份验证".我无法使用默认代理,因为我的代码是在没有默认代理设置的特殊帐户下从Windows服务运行的.所以,我想在我的代码中指定所有代理设置.请告诉我如何解决此错误.

我正在使用此代码将参数发送到网页并从中获取正确的响应.

System.Net.WebClient oWeb = new System.Net.WebClient();
oWeb.Proxy = System.Net.WebRequest.DefaultWebProxy;
oWeb.Proxy.Credentials = System.Net.CredentialCache.DefaultCredentials;
oWeb.Headers.Add("Content-Type", "application/x-www-form-urlencoded");
byte[] bytArguments = System.Text.Encoding.ASCII.GetBytes("value1=123&value2=xyz");
byte[] bytRetData = oWeb.UploadData("http://website.com/file.php", "POST", bytArguments);
response = System.Text.Encoding.ASCII.GetString(bytRetData);

但现在我想发送一个像(.doc)的文件+上面的参数(value1,value2),但我不知道该怎么做.

考虑一个简单的C#.NET Framework 4.0应用程序,它:

• 使用WebClient
• 使用NTLM进行身份验证(在IIS 6.0和IIS 7.5服务器上测试)
• 使用DownloadString()多次从URL检索字符串

这是一个工作正常的样本:

using System;
using System.Net;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string URL_status = "http://localhost/status";

            CredentialCache myCache = new CredentialCache();
            myCache.Add(new Uri(URL_status), "NTLM", new NetworkCredential("username", "password", "domain"));

            WebClient WebClient = new WebClient();
            WebClient.Credentials = myCache;

            for (int i = 1; i <= 5; i++)
            {
                string Result = WebClient.DownloadString(new Uri(URL_status));
                Console.WriteLine("Try " + i.ToString() + ": " + Result);
            }

            Console.Write("Done");
            Console.ReadKey();
        }
    }
}

问题:

启用跟踪时,我发现NTLM身份验证不会持久存在. …

当网络连接丢失3分钟或更长时间时,下面的WPF代码将永久挂起.当连接恢复时,它既不会抛出也不会继续下载或超时.如果网络连接在较短的时间内丢失(例如半分钟),则在连接恢复后会丢失.如何让网络中断更加强大？

using System;
using System.Net;
using System.Net.NetworkInformation;
using System.Windows;

namespace WebClientAsync
{

    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            NetworkChange.NetworkAvailabilityChanged +=
                (sender, e) => Dispatcher.Invoke(delegate()
                    {
                        this.Title = "Network is " + (e.IsAvailable ? " available" : "down");
                    });
        }

        const string SRC = "http://ovh.net/files/10Mio.dat";
        const string TARGET = @"d:\stuff\10Mio.dat";

        private async void btnDownload_Click(object sender, RoutedEventArgs e)
        {
            btnDownload.IsEnabled = false;
            btnDownload.Content = "Downloading " + SRC;
            try {
                using (var wcl = new WebClient())
                { …

我没有看到这两种方法之间有任何主要的时间复杂度差异，它们都有工作魅力，我想了解这两种方法之间的主要区别是什么

我正在从服务中收集学生对象。

bodyToMono 参数化类型参考

public Mono<Collection<Student>> getStudents(String id) {

    return webClient
         .get()
         .uri(uriBuilder -> uriBuilder
             .path("/students/{0}")
             .build(id))
         .retrieve()
         .onStatus(HttpStatus::isError, resp -> resp.createException()
             .map(WebClientGraphqlException::new)
             .flatMap(Mono::error)
         ).bodyToMono(new ParameterizedTypeReference<Collection<Student>>() {}); // This Line
  }

bodyToFlux 收集器

public Mono<Collection<Student>> getStudents(String id) {

    return webClient
         .get()
         .uri(uriBuilder -> uriBuilder
             .path("/students/{0}")
             .build(id))
         .retrieve()
         .onStatus(HttpStatus::isError, resp -> resp.createException()
             .map(WebClientGraphqlException::new)
             .flatMap(Mono::error)
         ).bodyToFlux(Student.class).collect(Collectors.toList()); // This Line
  }

我试图从我们的TFS服务器上的报告服务实例下载一些数据.
鉴于代码应该在未加入域的计算机上运行,​​我想我会自己设置凭据.没有运气,得到了一个HTTP 401 Unauthorized返回.好的,所以我联系了Fiddler看看发生了什么.

但是当我得到Heisenberged时 - 这个电话现在顺利完成了.因此认证通过Fiddler连接,但没有它就失败了.Webclient是破碎的还是我错过了一些深刻的东西？

private void ThisWorksWhenDomainJoined()
    {
        WebClient wc = new WebClient();
        wc.Credentials = CredentialCache.DefaultNetworkCredentials;
        wc.DownloadString("http://teamfoundationserver/reports/........");  //Works
    }

    private void ThisDoesntWork()
    {
        WebClient wc = new WebClient();
        wc.Credentials = new NetworkCredential("username", "password", "domain");
        wc.DownloadString("http://teamfoundationserver/reports/........");  //blows up wih HTTP 401
    }

我试图在WinForms应用程序中使用System.Net.WebClient将文件上传到具有Windows身份验证的IIS6服务器,因为它只是"身份验证"方法.

WebClient myWebClient = new WebClient();
myWebClient.Credentials = new System.Net.NetworkCredential(@"boxname\peter", "mypassword"); 
byte[] responseArray = myWebClient.UploadFile("http://localhost/upload.aspx", fileName);

我得到一个'远程服务器返回错误:(401)未授权',实际上它是401.2

客户端和IIS都在同一台Windows Server 2003 Dev计算机上.

当我尝试在Firefox中打开页面并输入与代码中相同的正确凭据时,页面出现.但是,当使用IE8时,我得到相同的401.2错误.

试过Chrome和Opera,他们都工作.

我在IE Internet选项中启用了"启用集成Windows身份验证".

安全事件日志具有失败审核:

Logon Failure:
    Reason:     An error occurred during logon
    User Name:  peter
    Domain:     boxname
    Logon Type: 3
    Logon Process:  ÈùÄ
    Authentication Package: NTLM
    Workstation Name:   boxname
    Status code:    0xC000006D
    Substatus code: 0x0
    Caller User Name:   -
    Caller Domain:  -
    Caller Logon ID:    -
    Caller Process ID:  -
    Transited Services: -
    Source Network Address: 127.0.0.1
    Source …