Aliyun.OSS.Util.HttpUtils.GetContentType C# (CSharp) Method

        public static string GetContentType(string key, string file)
        {
            string fileType = "";
            if (file != null)
            {
                fileType = System.IO.Path.GetExtension(file);
            } else if (key != null)
            {
                fileType = System.IO.Path.GetExtension(key);
            }

            fileType = fileType.Trim().TrimStart(new char[1] { '.' });

            if (_mimeDict.ContainsKey(fileType))
            {
                return _mimeDict[fileType];
            }

            return DefaultContentType;
        }