/// <summary>
/// Creates an instance of the Attachment class used by the MailMessage class to store mail
/// message attachments.
/// </summary>
/// <param name="part">The MIME body part to create the attachment from.</param>
/// <param name="bytes">An array of bytes composing the content of the attachment.</param>
/// <returns>An initialized instance of the Attachment class.</returns>
Attachment CreateAttachment(Bodypart part, byte[] bytes)
{
MemoryStream stream = new MemoryStream(bytes);
string name = part.Disposition.Filename;
// Many MUAs put the file name in the name parameter of the content-type header instead of
// the filename parameter of the content-disposition header.
if (String.IsNullOrEmpty(name) && part.Parameters.ContainsKey("name"))
name = part.Parameters["name"];
if (String.IsNullOrEmpty(name))
name = Path.GetRandomFileName();
Attachment attachment = new Attachment(stream, name);
try
{
attachment.ContentId = ParseMessageId(part.Id);
}
catch { }
try
{
attachment.ContentType = new System.Net.Mime.ContentType(
part.Type.ToString().ToLower() + "/" + part.Subtype.ToLower());
}
catch
{
attachment.ContentType = new System.Net.Mime.ContentType();
}
// Workaround: filename from Attachment constructor is ignored with Mono.
attachment.Name = name;
attachment.ContentDisposition.FileName = name;
return attachment;
}
/// <summary>
/// Adds a body part to an existing MailMessage instance.
/// </summary>
/// <param name="message">Extension method for the MailMessage class.</param>
/// <param name="part">The body part to add to the MailMessage instance.</param>
/// <param name="content">The content of the body part.</param>
internal void AddBodypart(MailMessage message, Bodypart part, string content)
{
Encoding encoding = part.Parameters.ContainsKey("Charset") ?
Util.GetEncoding(part.Parameters["Charset"]) : Encoding.ASCII;
// Decode the content if it is encoded.
byte[] bytes;
try
{
switch (part.Encoding)
{
case ContentTransferEncoding.QuotedPrintable:
bytes = encoding.GetBytes(Util.QPDecode(content, encoding));
break;
case ContentTransferEncoding.Base64:
bytes = Util.Base64Decode(content);
break;
default:
bytes = Encoding.ASCII.GetBytes(content);
break;
}
}
catch
{
// If it's not a valid Base64 or quoted-printable encoded string just leave the data as is.
bytes = Encoding.ASCII.GetBytes(content);
}
// If the part has a name it most likely is an attachment and it should go into the
// Attachments collection.
bool hasName = part.Parameters.ContainsKey("name");
// If the MailMessage's Body fields haven't been initialized yet, put it there. Some weird
// (i.e. spam) mails like to omit content-types so we don't check for that here and just
// assume it's text.
if (String.IsNullOrEmpty(message.Body) &&
part.Disposition.Type != ContentDispositionType.Attachment)
{
message.Body = encoding.GetString(bytes);
message.BodyEncoding = encoding;
message.IsBodyHtml = part.Subtype.ToLower() == "html";
return;
}
// Check for alternative view.
string ContentType = ParseMIMEField(message.Headers["Content-Type"])["value"];
bool preferAlternative = string.Compare(ContentType, "multipart/alternative", true) == 0;
// Many attachments are missing the disposition-type. If it's not defined as alternative
// and it has a name attribute, assume it is Attachment rather than an AlternateView.
if (part.Disposition.Type == ContentDispositionType.Attachment ||
(part.Disposition.Type == ContentDispositionType.Unknown &&
preferAlternative == false && hasName))
message.Attachments.Add(CreateAttachment(part, bytes));
else
message.AlternateViews.Add(CreateAlternateView(part, bytes));
}
/// <summary>
/// Creates an instance of the AlternateView class used by the MailMessage class to store
/// alternate views of the mail message's content.
/// </summary>
/// <param name="part">The MIME body part to create the alternate view from.</param>
/// <param name="bytes">An array of bytes composing the content of the alternate view.</param>
/// <returns>An initialized instance of the AlternateView class.</returns>
AlternateView CreateAlternateView(Bodypart part, byte[] bytes)
{
MemoryStream stream = new MemoryStream(bytes);
System.Net.Mime.ContentType contentType;
try
{
contentType = new System.Net.Mime.ContentType(
part.Type.ToString().ToLower() + "/" + part.Subtype.ToLower());
}
catch
{
contentType = new System.Net.Mime.ContentType();
}
AlternateView view = new AlternateView(stream, contentType);
try
{
view.ContentId = ParseMessageId(part.Id);
}
catch { }
return view;
}
/// <summary>
/// Glue method to create a bodypart from a MIMEPart instance.
/// </summary>
/// <param name="mimePart">The MIMEPart instance to create the bodypart instance from.</param>
/// <returns>An initialized instance of the Bodypart class.</returns>
Bodypart BodypartFromMIME(MIMEPart mimePart)
{
NameValueCollection contentType = ParseMIMEField(
mimePart.Headers["Content-Type"]);
Bodypart p = new Bodypart(null);
Match m = Regex.Match(contentType["value"], "(.+)/(.+)");
if (m.Success)
{
p.Type = ContentTypeMap.fromString(m.Groups[1].Value);
p.Subtype = m.Groups[2].Value;
}
p.Encoding = ContentTransferEncodingMap.fromString(
mimePart.Headers["Content-Transfer-Encoding"]);
p.Id = mimePart.Headers["Content-Id"];
foreach (string k in contentType.AllKeys)
p.Parameters.Add(k, contentType[k]);
p.Size = mimePart.MessageText.Length;
if (mimePart.Headers["Content-Disposition"] != null)
{
NameValueCollection disposition = ParseMIMEField(
mimePart.Headers["Content-Disposition"]);
p.Disposition.Type = ContentDispositionTypeMap.fromString(
disposition["value"]);
p.Disposition.Filename = disposition["Filename"];
foreach (string k in disposition.AllKeys)
p.Disposition.Attributes.Add(k, disposition[k]);
}
return p;
}
