NetCore HttpClient

using System;
using System.IO;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;

/// <summary>
/// HTTP辅助类。
/// </summary>
public static class CommonHttpHelper
{
    /// <summary>
    /// 用户代理。
    /// </summary>
    public const string UserAgent =
        "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.116 Safari/537.36";

    /// <summary>
    /// 请求远程地址，返回html。编码[gb2312,utf-8]
    /// </summary>
    /// <param name="requestHost">主机地址</param>
    /// <param name="requestUrl">请求地址</param>
    /// <param name="encoding">编码[gb2312,utf-8]</param>
    /// <returns></returns>
    public static async Task<string> GetHtmlAsync(string requestHost, string requestUrl,string encoding)
    {
        using (var client = new HttpClient())
        {
            client.DefaultRequestHeaders.Referrer = new Uri(requestHost);
            client.DefaultRequestHeaders.Add("User-Agent", UserAgent);

            //将 GET 请求发送到指定 URI 并在异步操作中以[流的形式]返回响应正文。
            using (var stream = await client.GetStreamAsync(requestUrl))
            {
                using (var reader = new StreamReader(stream, Encoding.GetEncoding(encoding)))
                {
　　　　　　　　　　　 //内容
                    var content = await reader.ReadToEndAsync();
                    return content;
                }
            }
        }
    }
}

string sContent = await CommonHttpHelper.GetHtmlAsync("https://" + host, url, "gb2312");

 

public async Task<string> GetDataAsync<TResult>(string url, Action<StringCollection> query) where TResult : ClientResult
{
    using (var client = new HttpClient())
    {
        try
        {
            //将 GET 请求发送到指定 URI 并在异步操作中以字符串的形式返回响应正文。
            //内容
            var json = await client.GetStringAsync(url);
            if (string.IsNullOrEmpty(json))
                return null;
            return json;
            //return JsonConvert.DeserializeObject<TResult>(json);
        }
        catch (Exception ex)
        {
            var error = $"GET错误: { ex.Message}\r\n发送地址：{ url}";
            return null;
        }
    }
}
public async Task<string> PostDataAsync<TResult>(string url, Action<StringCollection> data) where TResult : ClientResult
{
    using (var client = new HttpClient())
    {
        var postData = new StringCollection();
        data?.Invoke(postData);
        try
        {
            //以异步操作将 POST 请求发送给指定 URI。
            HttpResponseMessage response = await client.PostAsync(url, postData);
            response.EnsureSuccessStatusCode();
            //内容
            var json = await response.Content.ReadAsStringAsync();
            if (string.IsNullOrEmpty(json))
                return null;
            return json;
            //return JsonConvert.DeserializeObject<TResult>(json);
        }
        catch (Exception ex)
        {
            var error = $"GET错误: { ex.Message}\r\n发送地址：{ url}\r\n发送数据：{postData}";
            return null;
        }
    }
}