如何使用c#上传base64编码的数据

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            string inputStr = "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";
            string time = "Ef1ae0cH2GI3Ef1cH2GI3KM7Ij5gL6";//DateTime.Now.Ticks.ToString("x");
            string boundary = "----------" + time;
            string boundary2 = "------------" + time;
            string uploadUrl = "**";
            HttpWebRequest webrequest = (HttpWebRequest)WebRequest.Create(uploadUrl);
            webrequest.Headers["X-Requested-With"] = "ShockwaveFlash/17.0.0.134";
            webrequest.Headers["Accept-Encoding"] = "gzip, deflate";
            webrequest.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.89 Safari/537.36";
            webrequest.Accept = "*/*";
            webrequest.ContentType = "multipart/form-data; boundary=" + boundary;
            webrequest.Method = "POST";
            StringBuilder sb = new StringBuilder();
            sb.Append("--");
            sb.Append(boundary);
            sb.Append("\r\n");
            sb.Append("Content-Disposition: form-data; name=\"Filename\"");
            sb.Append("\r\n");
            sb.Append("\r\n");
            sb.Append("1.png");
            sb.Append("\r\n");
            sb.Append("--");
            sb.Append(boundary);
            sb.Append("\r\n");
            sb.Append("Content-Disposition: form-data; name=\"Filedata\"; filename=\"1.png\"");
            sb.Append("\r\n");
            sb.Append("Content-Type: application/octet-stream");
            sb.Append("\r\n");
            sb.Append("\r\n");
            StringBuilder bs = new StringBuilder();
            bs.Append("\r\n");
            bs.Append("--");
            bs.Append(boundary);
            bs.Append("\r\n");
            bs.Append("Content-Disposition: form-data; name=\"Upload\"");
            bs.Append("\r\n");
            bs.Append("\r\n");
            bs.Append("Submit Query");
            bs.Append("\r\n");
            bs.Append("--");
            bs.Append(boundary + "--");
            string postHeader = sb.ToString();
            string postEnder = bs.ToString();
            byte[] postHeaderBytes = Encoding.UTF8.GetBytes(postHeader);
            byte[] boundaryBytes = Encoding.ASCII.GetBytes(postEnder);
            byte[] buffer = GetByteImage(inputStr);
            long length = postHeaderBytes.Length + boundaryBytes.Length + buffer.Length;
            webrequest.ContentLength = length;
            Stream requestStream = webrequest.GetRequestStream();
            requestStream.Write(postHeaderBytes, 0, postHeaderBytes.Length);
            requestStream.Write(buffer, 0, buffer.Length);
            requestStream.Write(boundaryBytes, 0, boundaryBytes.Length);
            WebResponse response = webrequest.GetResponse();
            StreamReader sr = new StreamReader(response.GetResponseStream(), System.Text.Encoding.Default);//实例华一个流的读写器
            Console.WriteLine(sr.ReadToEnd());
            response.Close();
            requestStream.Close();
            Console.Read();
        }

        private static byte[] GetByteImage(string inputStr)
        {
            byte[] arr = Convert.FromBase64String(inputStr);
            using (MemoryStream ms = new MemoryStream(arr))
            {
                using (Bitmap bmp = new Bitmap(ms))
                {
                    using (MemoryStream stream = new MemoryStream())
                    {
                        bmp.Save(stream, ImageFormat.Png);
                        stream.Position = 0;
                        byte[] buffer = new byte[stream.Length];
                        stream.Read(buffer, 0, buffer.Length);
                        stream.Flush();
                        return buffer;
                    }

                }
            }

        }

    }
}

公司提的新需求 上传剪贴板的图片

出于公司隐私保护这里我不贴图片服务器接口的地址，主要这个地址没设权限

剪贴板取出来的数据是一个base64的字符串。经过一上午努力写出上传代码如上。

这里易出错的地方有2点

1.base64转出来的byte数组不能直接拿来写入stream必须将这个byte数组转换为bitmap再转成MemoryStream

写入stream才可以。

2.webrequest.ContentType的-比下面报文中的-少2个。

面对这种需求 装一个fiddler2 然后正常上传分析报文 模拟一个相同的报文就好了