重新想象 Windows 8.1 Store Apps (88)

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重新想象 Windows 8.1 Store Apps (88) - 通信的新特性: 新的 HttpClient

作者：webabcd


介绍
重新想象 Windows 8.1 Store Apps 之通信的新特性

• 新的 HttpClient
• http get string
• http get stream
• http post string
• http post stream

示例
HTTP 服务端
WebServer/HttpDemo.aspx.cs

/*
 * 用于响应 http 请求
 */

using System;
using System.IO;
using System.Threading;
using System.Web;

namespace WebServer
{
    public partial class HttpDemo : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            // 停 3 秒，以方便测试 http 请求的取消
            Thread.Sleep(3000);

            var action = Request.QueryString["action"];

            switch (action)
            {
                case "getString": // 响应 http get string 
                    Response.Write("hello webabcd: " + DateTime.Now.ToString("hh:mm:ss"));
                    break;
                case "getStream": // 响应 http get stream 
                    Response.Write("hello webabcd hello webabcd hello webabcd hello webabcd hello webabcd hello webabcd hello webabcd hello webabcd hello webabcd hello webabcd hello webabcd hello webabcd");
                    break;
                case "postString": // 响应 http post string 
                    Response.Write(string.Format("param1:{0}, param2:{1}, referrer:{2}", Request.Form["param1"], Request.Form["param2"], Request.UrlReferrer));
                    break;
                case "postStream": // 响应 http post stream 
                    using (StreamReader reader = new StreamReader(Request.InputStream))
                    {
                        if (Request.InputStream.Length > 1024 * 100)
                        {
                            // 接收的数据太大，则显示“数据接收成功”
                            Response.Write("数据接收成功");
                        }
                        else
                        {
                            // 显示接收到的数据
                            string body = reader.ReadToEnd();
                            Response.Write(Server.HtmlEncode(body));
                        }
                    } 
                    break;
                case "uploadFile": // 处理上传文件的请求
                    for (int i = 0; i < Request.Files.Count; i++)
                    {
                        string key = Request.Files.GetKey(i);
                        HttpPostedFile file = Request.Files.Get(key);
                        string savePath = @"d:" + file.FileName;

                        // 保存文件
                        file.SaveAs(savePath);

                        Response.Write(string.Format("key: {0}, fileName: {1}, savePath: {2}", key, file.FileName, savePath));
                        Response.Write("
");
                    }
                    break;
                case "outputCookie": // 用于显示服务端获取到的 cookie 信息
                    for (int i = 0; i < Request.Cookies.Count; i++)
                    {
                        HttpCookie cookie = Request.Cookies[0];
                        Response.Write(string.Format("cookieName: {0}, cookieValue: {1}", cookie.Name, cookie.Value));
                        Response.Write("
");
                    }
                    break;
                case "outputCustomHeader": // 用于显示一个自定义的 http header
                    Response.Write("myRequestHeader: " + Request.Headers["myRequestHeader"]);
                    break;
                default:
                    break;
            }

            Response.End();
        }
    }
}

1、演示新的 HttpClient
Summary.xaml.cs

/*
 * 本例简要说明新的命名空间 Windows.Web.Http 下的新的 HttpClient 的用法（其他相关类也均来自新的 Windows.Web.Http 命名空间）
 * 通过 HttpClient, HttpRequestMessage, HttpResponseMessage 实现 HTTP 通信
 * 
 * 
 * 在 win8.1 中增强了 HttpClient 的功能并将此增强版的 HttpClient 转移至了 Windows.Web.Http 命名空间下（原 win8 的 HttpClient 在 System.Net.Http 命名空间下，依旧可用）
 * 1、如果要查看 System.Net.Http 命名空间下的 HttpClient 的用法请参见：http://www.cnblogs.com/webabcd/archive/2013/09/23/3334233.html
 * 2、关于支持 OAuth 2.0 验证的客户端也请参见：http://www.cnblogs.com/webabcd/archive/2013/09/23/3334233.html
 * 
 * 
 * HttpClient - 用于发起 http 请求，以及接收 http 响应
 *     GetStringAsync(), GetAsync(), GetBufferAsync(), GetInputStreamAsync() - http get 请求
 *     DeleteAsync() - http delete 请求
 *     PostAsync(), PutAsync() - http post/put 请求
 *         参数：IHttpContent content - http 请求的数据
 *             实现了 IHttpContent 的类有：HttpStringContent, HttpBufferContent, HttpStreamContent, HttpFormUrlEncodedContent, HttpMultipartFormDataContent 等
 *         参数：HttpCompletionOption completionOption（HttpCompletionOption 枚举）
 *             ResponseContentRead - 获取到全部内容后再返回数据，默认值
 *             ResponseHeadersRead - 获取到头信息后就返回数据，用于流式获取
 *     SendRequestAsync() - 根据指定的 HttpRequestMessage 对象发起请求
 * 
 * HttpRequestMessage - http 请求
 *     Method - http 方法
 *     RequestUri - 请求的 uri
 *     Headers - http 的请求头信息
 *     Properties - 当做上下文用
 *     Content - http 请求的内容（IHttpContent 类型）
 *         实现了 IHttpContent 的类有：HttpStringContent, HttpBufferContent, HttpStreamContent, HttpFormUrlEncodedContent, HttpMultipartFormDataContent 等
 *     TransportInformation - 获取一个 HttpTransportInformation 类型的对象，用于 https 相关
 *         
 * HttpResponseMessage - http 响应
 *     RequestMessage - 对应的 HttpRequestMessage 对象
 *     Headers - http 的响应头信息
 *     Version - http 版本，默认是 1.1
 *     Source - 数据来源（HttpResponseMessageSource 枚举：Cache 或 Network）
 *     StatusCode - http 响应的状态码
 *     ReasonPhrase - http 响应的状态码所对应的短语
 *     IsSuccessStatusCode - http 响应的状态码是否是成功的值（200-299）
 *     EnsureSuccessStatusCode() - 当 IsSuccessStatusCode 为 false 时会抛出异常
 *     
 * 
 * 另：
 * win8 metro 的 http 抓包可用 fiddler
 * 
 * 还有：
 * http 通信还可以通过如下方法实现
 * HttpWebRequest webRequest = WebRequest.Create(url);
 */

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
using Windows.Web.Http;

namespace Windows81.Communication.HTTP
{
    public sealed partial class Summary : Page
    {
        private HttpClient _httpClient;
        private CancellationTokenSource _cts;

        public Summary()
        {
            this.InitializeComponent();
        }

        protected override void OnNavigatedFrom(NavigationEventArgs e)
        {
            // 释放资源
            if (_httpClient != null)
            {
                _httpClient.Dispose();
                _httpClient = null;
            }

            if (_cts != null)
            {
                _cts.Dispose();
                _cts = null;
            }
        }

        private async void btnPost_Click(object sender, RoutedEventArgs e)
        {
            _httpClient = new HttpClient();
            _cts = new CancellationTokenSource();

            try
            {
                string url = "http://localhost:39630/HttpDemo.aspx?action=postString";
                // 创建一个 HttpRequestMessage 对象
                HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, new Uri(url));

                // 需要 post 的数据
                HttpFormUrlEncodedContent postData = new HttpFormUrlEncodedContent(
                    new List<KeyValuePair<string, string>>
                    {
                        new KeyValuePair<string, string>("param1", "web"),
                        new KeyValuePair<string, string>("param2", "abcd")
                    }
                );

                // http 请求的数据
                request.Content = postData;
                // http 请求的头信息（叽歪一个，终于把 Referrer 改成 Referer 了）
                request.Headers.Referer = new Uri("http://webabcd.cnblogs.com");

                // 请求 HttpRequestMessage 对象，并返回 HttpResponseMessage 数据
                HttpResponseMessage response = await _httpClient.SendRequestAsync(request).AsTask(_cts.Token); // 取消请求的方式改为通过 CancellationTokenSource 来实现了

                // http 响应的状态码及其对应的短语
                lblMsg.Text += ((int)response.StatusCode) + " " + response.ReasonPhrase;
                lblMsg.Text += Environment.NewLine;

                // 以字符串的方式获取响应数据
                lblMsg.Text += await response.Content.ReadAsStringAsync();
                lblMsg.Text += Environment.NewLine;
            }
            catch (TaskCanceledException)
            {
                lblMsg.Text += "取消了";
                lblMsg.Text += Environment.NewLine;
            }
            catch (Exception ex)
            {
                lblMsg.Text += ex.ToString();
                lblMsg.Text += Environment.NewLine;
            }
        }

        private void btnCancel_Click(object sender, RoutedEventArgs e)
        {
            // 取消 http 请求
            if (_cts != null)
            {
                _cts.Cancel();
                _cts.Dispose();
                _cts = null;
            }
        }
    }
}

2、演示 http get string
GetString.xaml.cs

/*
 * 演示 http get string
 */

using System;
using System.Threading;
using System.Threading.Tasks;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
using Windows.Web.Http;

namespace Windows81.Communication.HTTP
{
    public sealed partial class GetString : Page
    {
        private HttpClient _httpClient;
        private CancellationTokenSource _cts;

        public GetString()
        {
            this.InitializeComponent();
        }

        protected override void OnNavigatedFrom(NavigationEventArgs e)
        {
            // 释放资源
            if (_httpClient != null)
            {
                _httpClient.Dispose();
                _httpClient = null;
            }

            if (_cts != null)
            {
                _cts.Dispose();
                _cts = null;
            }
        }

        private async void btnGetString_Click(object sender, RoutedEventArgs e)
        {
            _httpClient = new HttpClient();
            _cts = new CancellationTokenSource();

            try
            {
                HttpResponseMessage response = await _httpClient.GetAsync(new Uri("http://localhost:39630/HttpDemo.aspx?action=getString")).AsTask(_cts.Token); // 取消请求的方式改为通过 CancellationTokenSource 来实现了

                lblMsg.Text += ((int)response.StatusCode) + " " + response.ReasonPhrase;
                lblMsg.Text += Environment.NewLine;

                // IHttpContent.ReadAsStringAsync() - 获取 string 类型的响应数据
                // IHttpContent.ReadAsBufferAsync() - 获取 IBuffer 类型的响应数据
                // IHttpContent.ReadAsInputStreamAsync() - 获取 IInputStream 类型的响应数据
                lblMsg.Text += await response.Content.ReadAsStringAsync();
                lblMsg.Text += Environment.NewLine;
            }
            catch (TaskCanceledException)
            {
                lblMsg.Text += "取消了";
                lblMsg.Text += Environment.NewLine;
            }
            catch (Exception ex)
            {
                lblMsg.Text += ex.ToString();
                lblMsg.Text += Environment.NewLine;
            }
        }

        private void btnCancel_Click(object sender, RoutedEventArgs e)
        {
            // 取消 http 请求
            if (_cts != null)
            {
                _cts.Cancel();
                _cts.Dispose();
                _cts = null;
            }
        }
    }
}

3、演示 http get stream
GetStream.xaml.cs

/*
 * 演示 http get stream
 */

using System;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using Windows.Security.Cryptography;
using Windows.Storage.Streams;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
using Windows.Web.Http;

namespace Windows81.Communication.HTTP
{
    public sealed partial class GetStream : Page
    {
        private HttpClient _httpClient;
        private CancellationTokenSource _cts;

        public GetStream()
        {
            this.InitializeComponent();
        }

        protected override void OnNavigatedFrom(NavigationEventArgs e)
        {
            // 释放资源
            if (_httpClient != null)
            {
                _httpClient.Dispose();
                _httpClient = null;
            }

            if (_cts != null)
            {
                _cts.Dispose();
                _cts = null;
            }
        }

        private async void btnGetStream_Click(object sender, RoutedEventArgs e)
        {
            _httpClient = new HttpClient();
            _cts = new CancellationTokenSource();

            try
            {
                // HttpCompletionOption.ResponseHeadersRead - 获取到头信息后就返回数据，用于流式获取
                HttpResponseMessage response = await _httpClient.GetAsync(
                    new Uri("http://localhost:39630/HttpDemo.aspx?action=getStream"),
                    HttpCompletionOption.ResponseHeadersRead).AsTask(_cts.Token); // 取消请求的方式改为通过 CancellationTokenSource 来实现了

                lblMsg.Text += ((int)response.StatusCode) + " " + response.ReasonPhrase;
                lblMsg.Text += Environment.NewLine;

                // IHttpContent.ReadAsStringAsync() - 获取 string 类型的响应数据
                // IHttpContent.ReadAsBufferAsync() - 获取 IBuffer 类型的响应数据
                // IHttpContent.ReadAsInputStreamAsync() - 获取 IInputStream 类型的响应数据
                using (Stream responseStream = (await response.Content.ReadAsInputStreamAsync()).AsStreamForRead())
                {
                    byte[] buffer = new byte[32];
                    int read = 0;

                    while ((read = await responseStream.ReadAsync(buffer, 0, buffer.Length)) > 0)
                    {
                        lblMsg.Text += "读取的字节数: " + read.ToString();
                        lblMsg.Text += Environment.NewLine;

                        IBuffer responseBuffer = CryptographicBuffer.CreateFromByteArray(buffer);
                        lblMsg.Text += CryptographicBuffer.EncodeToHexString(responseBuffer);
                        lblMsg.Text += Environment.NewLine;

                        buffer = new byte[32];
                    }
                }
            }
            catch (TaskCanceledException)
            {
                lblMsg.Text += "取消了";
                lblMsg.Text += Environment.NewLine;
            }
            catch (Exception ex)
            {
                lblMsg.Text += ex.ToString();
                lblMsg.Text += Environment.NewLine;
            }
        }

        private void btnCancel_Click(object sender, RoutedEventArgs e)
        {
            // 取消 http 请求
            if (_cts != null)
            {
                _cts.Cancel();
                _cts.Dispose();
                _cts = null;
            }
        }
    }
}

4、演示 http post string
PostString.xaml.cs

/*
 * 演示 http post string
 */

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
using Windows.Web.Http;

namespace Windows81.Communication.HTTP
{
    public sealed partial class PostString : Page
    {
        private HttpClient _httpClient;
        private CancellationTokenSource _cts;

        public PostString()
        {
            this.InitializeComponent();
        }

        protected override void OnNavigatedFrom(NavigationEventArgs e)
        {
            // 释放资源
            if (_httpClient != null)
            {
                _httpClient.Dispose();
                _httpClient = null;
            }

            if (_cts != null)
            {
                _cts.Dispose();
                _cts = null;
            }
        }

        private async void btnPostString_Click(object sender, RoutedEventArgs e)
        {
            _httpClient = new HttpClient();
            _cts = new CancellationTokenSource();

            try
            {
                // 需要 post 的数据
                var postData = new HttpFormUrlEncodedContent(
                    new List<KeyValuePair<string, string>>
                    {
                        new KeyValuePair<string, string>("param1", "web"),
                        new KeyValuePair<string, string>("param2", "abcd")
                    }
                );

                HttpResponseMessage response = await _httpClient.PostAsync(
                    new Uri("http://localhost:39630/HttpDemo.aspx?action=postString"),
                    postData).AsTask(_cts.Token); // 取消请求的方式改为通过 CancellationTokenSource 来实现了

                lblMsg.Text += ((int)response.StatusCode) + " " + response.ReasonPhrase;
                lblMsg.Text += Environment.NewLine;

                // HttpContent.ReadAsStringAsync() - 以 string 方式获取响应数据
                // HttpContent.ReadAsByteArrayAsync() - 以 byte[] 方式获取响应数据
                // HttpContent.ReadAsStreamAsync() - 以 stream 方式获取响应数据
                lblMsg.Text += await response.Content.ReadAsStringAsync();
                lblMsg.Text += Environment.NewLine;
            }
            catch (TaskCanceledException)
            {
                lblMsg.Text += "取消了";
                lblMsg.Text += Environment.NewLine;
            }
            catch (Exception ex)
            {
                lblMsg.Text += ex.ToString();
                lblMsg.Text += Environment.NewLine;
            }
        }

        private void btnCancel_Click(object sender, RoutedEventArgs e)
        {
            // 取消 http 请求
            if (_cts != null)
            {
                _cts.Cancel();
                _cts.Dispose();
                _cts = null;
            }
        }
    }
}

5、演示 http post stream
PostStream.xaml.cs

/*
 * 演示 http post stream
 */

using System;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
using Windows.Web.Http;

namespace Windows81.Communication.HTTP
{
    public sealed partial class PostStream : Page
    {
        private HttpClient _httpClient;
        private CancellationTokenSource _cts;

        public PostStream()
        {
            this.InitializeComponent();
        }

        protected override void OnNavigatedFrom(NavigationEventArgs e)
        {
            // 释放资源
            if (_httpClient != null)
            {
                _httpClient.Dispose();
                _httpClient = null;
            }

            if (_cts != null)
            {
                _cts.Dispose();
                _cts = null;
            }
        }

        private async void btnPostStream_Click(object sender, RoutedEventArgs e)
        {
            _httpClient = new HttpClient();
            _cts = new CancellationTokenSource();

            try
            {
                // 需要 post 的 stream 数据
                Stream stream = GenerateSampleStream(128);
                HttpStreamContent streamContent = new HttpStreamContent(stream.AsInputStream());

                HttpResponseMessage response = await _httpClient.PostAsync(
                   new Uri("http://localhost:39630/HttpDemo.aspx?action=postStream"),
                   streamContent).AsTask(_cts.Token);// 取消请求的方式改为通过 CancellationTokenSource 来实现了

                lblMsg.Text += ((int)response.StatusCode) + " " + response.ReasonPhrase;
                lblMsg.Text += Environment.NewLine;

                // IHttpContent.ReadAsStringAsync() - 获取 string 类型的响应数据
                // IHttpContent.ReadAsBufferAsync() - 获取 IBuffer 类型的响应数据
                // IHttpContent.ReadAsInputStreamAsync() - 获取 IInputStream 类型的响应数据
                lblMsg.Text += await response.Content.ReadAsStringAsync();
                lblMsg.Text += Environment.NewLine;
            }
            catch (TaskCanceledException)
            {
                lblMsg.Text += "取消了";
                lblMsg.Text += Environment.NewLine;
            }
            catch (Exception ex)
            {
                lblMsg.Text += ex.ToString();
                lblMsg.Text += Environment.NewLine;
            }
        }

        // 生成一个指定大小的内存流
        private static MemoryStream GenerateSampleStream(int size)
        {
            byte[] subData = new byte[size];
            for (int i = 0; i < subData.Length; i++)
            {
                subData[i] = (byte)(97 + i % 26); // a-z
            }

            return new MemoryStream(subData);
        }

        private void btnCancel_Click(object sender, RoutedEventArgs e)
        {
            // 取消 http 请求
            if (_cts != null)
            {
                _cts.Cancel();
                _cts.Dispose();
                _cts = null;
            }
        }
    }
}

OK
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