之前玩了下百度bcs,觉得还不错，看了下云存储貌似没.net sdk  但是既然有api就好办嘛,自己动手写个文件上传试试

它的参数用了hmac签名,.net有自带的库,下面是签名方法,这个找了很久...参考着修改了下.还有个疑问,不知道百度是怎么验证签名内容的,因为我们只传入了sign，而hmac据说是不能解密的,只能用密钥来验证

        /// <summary>
        /// 对数据进行Hmac签名
        /// </summary>
        /// <param name="valueStr">要签名的数据</param>
        /// <param name="keyStr">密钥</param>
        /// <returns></returns>
        private string Hamc(string valueStr, string keyStr)
        {
            HMAC hmac = HMACSHA1.Create();
            //源数据
            var data = System.Text.Encoding.UTF8.GetBytes(valueStr);
            //密钥
            var key = System.Text.Encoding.UTF8.GetBytes(keyStr);
            //设置密钥
            hmac.Key = key;
            //计算哈希值
            var hash = hmac.ComputeHash(data);
            //对数据进行签名
            var signedData = hash.Concat(data).ToArray();
            var receivedHash = signedData.Take(hmac.HashSize >> 3).ToArray();

            String str = HttpUtility.UrlEncode(Convert.ToBase64String(receivedHash));

            return str;
        }

然后就是上传文件到服务器了，可以看着进行修改下,下面的方法检索了流的sha1,如果服务器存在则直接返回地址.这里流的读取有一个注意的地方,不能一次读取流的全部,因为某些流不支持查找操作,所以先设了个40kb的缓存

  /// <summary>
        /// 上传文件到百度空间,并写入文件数据库
        /// </summary>
        /// <param name="input">输入流 该流必须能够读取</param>
        /// <param name="fileName">上传的文件名</param>
        /// <param name="bucket"></param>
        /// <returns></returns>
        public string UploadToBaidu(Stream input, string fileName, string bucket = "kecq-com")
        {
            if (String.IsNullOrEmpty(fileName))
            {
                throw new Exception("savePath参数不能为空");
            }

            fileName = fileName.TrimStart('/');
            string savePath = "/" + DateTime.Now.Year + "/" + DateTime.Now.Month + "/" + DateTime.Now.Day + "/" + Guid.NewGuid().ToString("N") + Path.GetExtension(fileName);
            string fileUrl = "http://bcs.duapp.com/" + bucket + savePath;
            string Content = "MBO" + "\n"
          + "Method=PUT" + "\n"
          + "Bucket=kecq-com" + "\n"
          + "Object=" + savePath + "\n";
            string sign = Hamc(Content, "xxxxxxxxxxxxx");
            string url = "http://bcs.duapp.com/" + bucket + savePath + "?sign=MBO:D200252c02041aac02015b01656582bf:" + sign;
            HttpWebResponse res = null;
            string returnString = "";
            try
            {
                List<byte> data = new List<byte>();
                byte[] buffer = new byte[40960];
                int read = input.Read(buffer, 0, buffer.Length);
                while (read > 0)
                {
                    for (int i = 0; i < read; i++)
                    {
                        data.Add(buffer[i]);
                    }
                    read = input.Read(buffer, 0, buffer.Length);
                }
                input.Close();
                //获取流的sha1码
                System.Security.Cryptography.HashAlgorithm algorithm = System.Security.Cryptography.SHA1.Create();
                String sha1 = BitConverter.ToString(algorithm.ComputeHash(data.ToArray())).Replace("-", "");
                string writeDbUrl = "http://my.fyj.me/service/upload.action?method=POST&userID=xxxxxxxxx&flag=MU&ak=afbf3d192908477d9e24b3e351bc4ebe&sign=0PjZ80oM9HRgyJYGQtmawv2eiwI%3d";
                writeDbUrl += "&action=saveFileDb&fileSha1=" + sha1 + "&fileName=" + fileName + "&fileSize=" + data.Count + "&fileUrl=" + HttpUtility.UrlEncode(fileUrl);
                string result = FYJ.Common.HttpHelper.DoGet(writeDbUrl);
                FYJ.Common.JsonHelper json = new FYJ.Common.JsonHelper(result);
                if (json.GetValue("code") != "1")
                {
                    throw new Exception(json.GetValue("message"));
                }
                else
                {
                    returnString = result;
                }

                if (json.GetValue("isFileExist") == "0")
                {
                    HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
                    req.Method = "PUT";
                    req.ContentType = "application/x-www-form-urlencoded";
                    req.ContentLength = data.Count;
                    Stream newStream = req.GetRequestStream();
                    newStream.Write(data.ToArray(), 0, data.Count);
                    newStream.Close();

                    req.GetRequestStream();
                    res = (HttpWebResponse)req.GetResponse();
                    Stream ReceiveStream = res.GetResponseStream();
                    Encoding encode = System.Text.Encoding.UTF8;
                    StreamReader sr = new StreamReader(ReceiveStream, encode);
                    // strResult = sr.ReadToEnd();

                    sr.Close();
                    ReceiveStream.Close();
                }

                return returnString;
            }
            catch (Exception e)
            {
                return "{\"code\":\"-1\",\"msg\":\""+e.Message+"\"}";
            }
            finally
            {
                if (res != null)
                {
                    res.Close();
                }
            }
        }