twitter帐户/ update_profile_image 422错误

Question

我必须通过Twitter API 1.1上传头像，但我总是得到422错误。 这是我的代码：

var path = "avatar.jpg"; 
var req = token.GetQueryWebRequest("https://api.twitter.com/1.1/account/update_profile_image.json", HttpMethod.POST); 

ServicePointManager.Expect100Continue = false; /// ???????????? 

req.ContentType = "multipart/form-data"; 
var image = "image=" + Uri.EscapeDataString(getImageBase64Encode(path, 700)); 
var encode = Encoding.ASCII.GetBytes(image); 
req.ContentLength = encode.Length; 
var steam = req.GetRequestStream(); 
steam.Write(encode, 0, encode.Length); 
var resp = req.GetResponse(); 

// ---------------- 
private string getImageBase64Encode(string filePath, int maxSize) 
{ 
if (!File.Exists(filePath)) 
      throw new Exception(string.Format("Файл не существует: {0}", filePath)); 
var file = new FileInfo(filePath); 
if(file.Length > maxSize * 1024) 
      throw new Exception(string.Format("Файл слишком большой: {0}", filePath)); 

byte[] res = null; 
try 
{ 
    res = File.ReadAllBytes(filePath); 
} 
catch (Exception) 
{ 
    throw new Exception(string.Format("Неудалось прочитать файл: {0}", filePath)); 
} 
if (res == null) 
{ 
    throw new Exception(string.Format("Файл пуст или поврежден: {0}", filePath)); 
} 

return Convert.ToBase64String(res); 
} 

GetQueryWebRequest - 获得通过OAuth头请求

不提供框架

PS>对不起，我的英语那么差

Answer 1

我解决了这个问题：

var imageByte = GetImageByte(path, 800); 

var type = Path.GetExtension(path).Trim('.').ToLower(); 
var filename = Path.GetFileName(path); 

if (type == "jpg") type = "jpeg"; 

if (type != "jpeg" && type != "png" && type != "gif") throw new Exception("Неверный формат файла для загрузки на сервер"); 

const string boundary = "--0246824681357ACXZabcxyz"; 
req.ContentType = string.Format("multipart/form-data; type=\"image/{0}\"; start=\"<banner>\"; boundary=\"{1}\"", type, boundary); 
req.KeepAlive = true; 
var image = string.Format(
    "--{0}\r\n" + 
    "Content-Type: image/jpeg; name=\"banner\"\r\n" + 
    "Content-Transfer-Encoding: binary\r\n" + 
    "Content-ID: <image>\r\n" + 
    "Content-Disposition: form-data; name=\"banner\"; filename=\"{1}\"\r\n" + 
    "Content-Location: image\r\n" + 
    "\r\n", boundary, filename); 
var encode = Encoding.UTF8.GetBytes(image); 
var steam = req.GetRequestStream(); 
steam.Write(encode, 0, encode.Length); 

steam.Write(imageByte, 0, imageByte.Length); 

encode = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n"); 
steam.Write(encode, 0, encode.Length); 

req.GetResponse();