C# HttpClient 使用相关积累

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System.Net.Http 是微软推出的最新的 HTTP 应用程序的编程接口,
微软称之为“现代化的 HTTP
编程接口”,个人认为是一个比较好用的类库,毕竟不用组织大量的 http
请求头内容,用起来也相对比较方便,发送一个请求只需要几行代码,以下是自己应用
HttpClient 的一点积累:

1> HttpClient GET 请求:

using (HttpClient cli = new HttpClient())
{  
  var responseResult = cli.GetAsync(“请求地址”).Result;
  if (responseResult.IsSuccessStatusCode)
  {    
    var result =
responseResult.Content.ReadAsStringAsync().Result;
    Console.WriteLine(result);
  }
}

2> HttpClient POST 请求:

HttpClient POST
请求,需要构造请求内容(HttpContent,抽像类),类结构如下:

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 提交表单类数据:

 using (HttpClient cli = new HttpClient())
{
         var content = new FormUrlEncodedContent(new Dictionary<string, string>() { { "us", "us" }, { "pw", "pw" } });             
         var responseResult = cli.PostAsync("请求地址", content).Result;
         if (responseResult.IsSuccessStatusCode)
         {
              var result = responseResult.Content.ReadAsStringAsync().Result;
              Console.Write(result);
         }
 }

提交文件类数据:

 

3>
发送特殊请求:
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 1> 检查服务器是否支持分片下载;

using (HttpClient cli= new HttpClient())
{
        var responseResult = cli.SendAsync(new HttpRequestMessage(HttpMethod.Head, "请求路径")).Result;
        //true:支持,false:不支持;
        var isSuported = response.Headers.AcceptRanges.Contains("bytes");

}

 2> 分片下载数据; 

 using (var fileStream = new FileStream(saveAs, FileMode.Open, FileAccess.Write,FileShare.Write))
 {
        var message = new HttpRequestMessage(HttpMethod.Get, url);
        message.Headers.Add("Range", string.Format("bytes={0}-{1}", start, end));
        fileStream.Position = start;
        var responseR = await httpClient.SendAsync(message);
        await responseR.Content.CopyToAsync(fileStream);
 } 

 3> HttpClient 带 Cookie 请求;

var handler = new HttpClientHandler();
var cookies = new CookieContainer();
handler.CookieContainer = cookies;
using (var cli = new HttpClient(handler))
{
       var uri = new Uri("请求地址");
       var result = cli.GetAsync(uri).Result;         

       var responseCookies = cookies.GetCookies(uri).Cast<Cookie>();
}

 4> HttpClient Post JSON 数据;

            using (var cli = new HttpClient())
            {
                cli.DefaultRequestHeaders.Accept.Clear();
                cli.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                var result = await cli.PostAsJsonAsync(rUrl, new {a="",b=""});
                //var result = await cli.PostAsync(rUrl, new StringContent(jsonstring));
                if (result.IsSuccessStatusCode)
                {
                   //do something
                }                
            }