Amazon.S3.Util.AmazonS3Util.MimeTypeFromExtension C# (CSharp) Method

        public static string MimeTypeFromExtension(string ext)
        {
            if (extensionToMime.ContainsKey(ext))
            {
                return extensionToMime[ext];
            }
            else
            {
                return "application/octet-stream";
            }
        }

        /// <summary>
        /// Write the multipart/form-data for this request for all fields except the file data to a stream
        /// </summary>
        internal void WriteFormData(string boundary, Stream outputStream)
        {
            if (!String.IsNullOrEmpty(this.Key))
            {
                WriteFormDatum(outputStream, S3Constants.PostFormDataObjectKey, this.Key, boundary);
            }

            WriteFormDatum(outputStream, S3Constants.PostFormDataAcl, this.CannedACL, boundary);

            if (this._isSetStorageClass)
            {
                WriteFormDatum(outputStream, HeaderKeys.XAmzStorageClassHeader, this.StorageClass, boundary);
            }

            if (this._isSetActionStatus)
            {
                WriteFormDatum(outputStream, S3Constants.PostFormDataStatus, ((Int32)this.SuccessActionStatus).ToString(CultureInfo.InvariantCulture), boundary);
            }

            if (!String.IsNullOrEmpty(this.SuccessActionRedirect))
            {
                WriteFormDatum(outputStream, S3Constants.PostFormDataRedirect, this.SuccessActionRedirect, boundary);
            }

            if (String.IsNullOrEmpty(this.ContentType))
            {
                if (this.Key.IndexOf('.') > -1)
                {
                    this.ContentType = AmazonS3Util.MimeTypeFromExtension(this.Key.Substring(this.Key.LastIndexOf('.')));
                }
                else if (!String.IsNullOrEmpty(this.Path) && this.Path.IndexOf('.') > -1)
                {
                    this.ContentType = AmazonS3Util.MimeTypeFromExtension(this.Key.Substring(this.Path.LastIndexOf('.')));
                }
            }

            WriteFormDatum(outputStream, S3Constants.PostFormDataContentType, this.ContentType, boundary);

            if (this.SignedPolicy != null && !string.IsNullOrEmpty(this.SignedPolicy.SecurityToken))
            {
                this.Metadata[S3Constants.PostFormDataSecurityToken] = this.SignedPolicy.SecurityToken;
            }

            foreach (var kvp in this.Metadata)
            {
                var metakey = kvp.Key.StartsWith(S3Constants.PostFormDataXAmzPrefix, StringComparison.Ordinal) ? kvp.Key : S3Constants.PostFormDataMetaPrefix + kvp.Key;
                WriteFormDatum(outputStream, metakey, kvp.Value, boundary);
            }

            if (this.SignedPolicy != null)
            {
                WriteFormDatum(outputStream, S3Constants.PostFormDataAccessKeyId, this.SignedPolicy.AccessKeyId, boundary);
                WriteFormDatum(outputStream, S3Constants.PostFormDataPolicy, this.SignedPolicy.Policy, boundary);
                WriteFormDatum(outputStream, S3Constants.PostFormDataSignature, this.SignedPolicy.Signature, boundary);
            }
        }