private void DecodeEntity(RxMailMessage entity)
{
AppendLine("From : {0}", entity.From);
AppendLine("Sender: {0}", entity.Sender);
AppendLine("To : {0}", entity.To);
AppendLine("CC : {0}", entity.CC);
AppendLine("ReplyT: {0}", string.Join(";", Array.ConvertAll(entity.ReplyToList.ToArray(), i => i.Address)));
AppendLine("Sub : {0}", entity.Subject);
AppendLine("S-Enco: {0}", entity.SubjectEncoding);
if (entity.DeliveryDate > DateTime.MinValue)
{
AppendLine("Date : {0}", entity.DeliveryDate);
}
if (entity.Priority != MailPriority.Normal)
{
AppendLine("Priori: {0}", entity.Priority);
}
if (entity.Body.Length > 0)
{
AppendLine("Body : {0} byte(s)", entity.Body.Length);
AppendLine("B-Enco: {0}", entity.BodyEncoding);
}
else
{
if (entity.BodyEncoding != Encoding.ASCII)
{
AppendLine("B-Enco: {0}", entity.BodyEncoding);
}
}
AppendLine("T-Type: {0}", entity.TransferType);
AppendLine("C-Type: {0}", entity.ContentType);
AppendLine("C-Desc: {0}", entity.ContentDescription);
AppendLine("C-Disp: {0}", entity.ContentDisposition);
AppendLine("C-Id : {0}", entity.ContentId);
AppendLine("M-ID : {0}", entity.MessageId);
AppendLine("Mime : Version {0}", entity.MimeVersion);
if (entity.ContentStream != null)
{
AppendLine("Stream: Length {0}", entity.ContentStream.Length);
}
//decode all shild MIME entities
foreach (RxMailMessage child in entity.Entities)
{
_mailStructure.AppendLine("------------------------------------");
DecodeEntity(child);
}
if (entity.ContentType != null && entity.ContentType.MediaType != null && entity.ContentType.MediaType.StartsWith("multipart"))
{
AppendLine("End {0}", entity.ContentType.ToString());
}
}
// Constructors
// ------------
/// <summary>
/// default constructor
/// </summary>
public RxMailMessage()
{
//for the moment, we assume to be at the top
//should this entity become a child, TopParent will be overwritten
TopParent = this;
Entities = new List<RxMailMessage>();
UnknowHeaderlines = new List<string>();
}
/// <summary>
/// Creates an empty child MIME entity from the parent MIME entity.
///
/// An email can consist of several MIME entities. A entity has the same structure
/// like an email, that is header and body. The child inherits few properties
/// from the parent as default value.
/// </summary>
public RxMailMessage CreateChildEntity()
{
var child = new RxMailMessage
{
Parent = this,
TopParent = TopParent,
ContentTransferEncoding = ContentTransferEncoding
};
return child;
}
/// <summary>
/// each attachement is stored in its own MIME entity and read into this entity's
/// ContentStream. SaveAttachment creates an attachment out of the ContentStream
/// and attaches it to the parent MIME entity.
/// </summary>
private void SaveAttachment(RxMailMessage message)
{
if (message.Parent == null)
{
System.Diagnostics.Debugger.Break(); //didn't have a sample email to test this
}
else
{
Attachment thisAttachment = new Attachment(message.ContentStream, message.ContentType);
//no idea why ContentDisposition is read only. on the other hand, it is anyway redundant
if (message.ContentDisposition != null)
{
ContentDisposition messageContentDisposition = message.ContentDisposition;
ContentDisposition AttachmentContentDisposition = thisAttachment.ContentDisposition;
if (messageContentDisposition.CreationDate > DateTime.MinValue)
{
AttachmentContentDisposition.CreationDate = messageContentDisposition.CreationDate;
}
AttachmentContentDisposition.DispositionType = messageContentDisposition.DispositionType;
AttachmentContentDisposition.FileName = messageContentDisposition.FileName;
AttachmentContentDisposition.Inline = messageContentDisposition.Inline;
if (messageContentDisposition.ModificationDate > DateTime.MinValue)
{
AttachmentContentDisposition.ModificationDate = messageContentDisposition.ModificationDate;
}
AttachmentContentDisposition.Parameters.Clear();
if (messageContentDisposition.ReadDate > DateTime.MinValue)
{
AttachmentContentDisposition.ReadDate = messageContentDisposition.ReadDate;
}
if (messageContentDisposition.Size > 0)
{
AttachmentContentDisposition.Size = messageContentDisposition.Size;
}
foreach (string key in messageContentDisposition.Parameters.Keys)
{
AttachmentContentDisposition.Parameters.Add(key, messageContentDisposition.Parameters[key]);
}
}
//get ContentId
string contentIdString = message.ContentId;
if (contentIdString != null)
{
thisAttachment.ContentId = RemoveBrackets(contentIdString);
}
thisAttachment.TransferEncoding = message.ContentTransferEncoding;
message.Parent.Attachments.Add(thisAttachment);
}
}
/// <summary>
/// Copies the content found for the MIME entity to the RxMailMessage body and creates
/// a stream which can be used to create attachements, alternative views, ...
/// </summary>
private void saveMessageBody(RxMailMessage message, string contentString)
{
message.Body = contentString;
MemoryStream bodyStream = new MemoryStream();
StreamWriter bodyStreamWriter = new StreamWriter(bodyStream);
bodyStreamWriter.Write(contentString);
int l = contentString.Length;
bodyStreamWriter.Flush();
message.ContentStream = bodyStream;
}
/// <summary>
/// Process a MIME entity
///
/// A MIME entity consists of header and body.
/// Separator lines in the body might mark children MIME entities
/// </summary>
private MimeEntityReturnCode ProcessMimeEntity(RxMailMessage message, string parentBoundaryStart)
{
bool hasParentBoundary = parentBoundaryStart.Length > 0;
string parentBoundaryEnd = parentBoundaryStart + "--";
MimeEntityReturnCode boundaryMimeReturnCode;
//some format fields are inherited from parent, only the default for
//ContentType needs to be set here, otherwise the boundary parameter would be
//inherited too !
message.SetContentTypeFields("text/plain; charset=us-ascii");
//get header
//----------
string completeHeaderField = null; //consists of one start line and possibly several continuation lines
string response;
// read header lines until empty line is found (end of header)
while (true)
{
if (!readMultiLine(out response))
{
//POP3 server has not send any more lines
callGetEmailWarning("incomplete MIME entity header received");
//empty this message
while (readMultiLine(out response)) { }
System.Diagnostics.Debugger.Break(); //didn't have a sample email to test this
return MimeEntityReturnCode.problem;
}
if (response.Length < 1)
{
//empty line found => end of header
if (completeHeaderField != null)
{
ProcessHeaderField(message, completeHeaderField);
}
else
{
//there was only an empty header.
}
break;
}
//check if there is a parent boundary in the header (wrong format!)
if (hasParentBoundary && parentBoundaryFound(response, parentBoundaryStart, parentBoundaryEnd, out boundaryMimeReturnCode))
{
callGetEmailWarning("MIME entity header prematurely ended by parent boundary");
//empty this message
while (readMultiLine(out response)) { }
System.Diagnostics.Debugger.Break(); //didn't have a sample email to test this
return boundaryMimeReturnCode;
}
//read header field
//one header field can extend over one start line and multiple continuation lines
//a continuation line starts with at least 1 blank (' ') or tab
if (response[0] == ' ' || response[0] == '\t')
{
//continuation line found.
if (completeHeaderField == null)
{
callGetEmailWarning("Email header starts with continuation line");
//empty this message
while (readMultiLine(out response)) { }
System.Diagnostics.Debugger.Break(); //didn't have a sample email to test this
return MimeEntityReturnCode.problem;
}
else
{
// append space, if needed, and continuation line
if (completeHeaderField[completeHeaderField.Length - 1] != ' ')
{
//previous line did not end with a whitespace
//need to replace CRLF with a ' '
completeHeaderField += ' ' + response.TrimStart(WhiteSpaceChars);
}
else
{
//previous line did end with a whitespace
completeHeaderField += response.TrimStart(WhiteSpaceChars);
}
}
}
else
{
//a new header field line found
if (completeHeaderField == null)
{
//very first field, just copy it and then check for continuation lines
completeHeaderField = response;
}
else
{
//new header line found
ProcessHeaderField(message, completeHeaderField);
//save the beginning of the next line
completeHeaderField = response;
}
}
}//end while read header lines
//process body
//------------
MimeEntitySB.Length = 0; //empty StringBuilder. For speed reasons, reuse StringBuilder defined as member of class
string BoundaryDelimiterLineStart = null;
bool isBoundaryDefined = false;
if (message.ContentType.Boundary != null)
{
isBoundaryDefined = true;
BoundaryDelimiterLineStart = "--" + message.ContentType.Boundary;
}
//prepare return code for the case there is no boundary in the body
boundaryMimeReturnCode = MimeEntityReturnCode.bodyComplete;
//read body lines
while (readMultiLine(out response))
{
//check if there is a boundary line from this entity itself in the body
if (isBoundaryDefined && response.TrimEnd() == BoundaryDelimiterLineStart)
{
//boundary line found.
//stop the processing here and start a delimited body processing
return ProcessDelimitedBody(message, BoundaryDelimiterLineStart, parentBoundaryStart, parentBoundaryEnd);
}
//check if there is a parent boundary in the body
if (hasParentBoundary &&
parentBoundaryFound(response, parentBoundaryStart, parentBoundaryEnd, out boundaryMimeReturnCode))
{
//a parent boundary is found. Decode the content of the body received so far, then end this MIME entity
//note that boundaryMimeReturnCode is set here, but used in the return statement
break;
}
//process next line
MimeEntitySB.Append(response + CRLF);
}
//a complete MIME body read
//convert received US ASCII characters to .NET string (Unicode)
string TransferEncodedMessage = MimeEntitySB.ToString();
bool isAttachmentSaved = false;
switch (message.ContentTransferEncoding)
{
case TransferEncoding.SevenBit:
//nothing to do
saveMessageBody(message, TransferEncodedMessage);
break;
case TransferEncoding.Base64:
//convert base 64 -> byte[]
byte[] bodyBytes = System.Convert.FromBase64String(TransferEncodedMessage);
message.ContentStream = new MemoryStream(bodyBytes, false);
if (message.MediaMainType == "text")
{
//convert byte[] -> string
message.Body = DecodeByteArryToString(bodyBytes, message.BodyEncoding);
}
else if (message.MediaMainType == "image" || message.MediaMainType == "application")
{
SaveAttachment(message);
isAttachmentSaved = true;
}
break;
case TransferEncoding.QuotedPrintable:
saveMessageBody(message, QuotedPrintable.Decode(TransferEncodedMessage));
break;
default:
saveMessageBody(message, TransferEncodedMessage);
//no need to raise a warning here, the warning was done when analising the header
break;
}
if (message.ContentDisposition != null && message.ContentDisposition.DispositionType.ToLowerInvariant() == "attachment" && !isAttachmentSaved)
{
SaveAttachment(message);
isAttachmentSaved = true;
}
return boundaryMimeReturnCode;
}
/// <summary>
/// Convert one MIME header field and update message accordingly
/// </summary>
private void ProcessHeaderField(RxMailMessage message, string headerField)
{
string headerLineType;
string headerLineContent;
int separatorPosition = headerField.IndexOf(':');
if (separatorPosition < 1)
{
// header field type not found, skip this line
callGetEmailWarning("character ':' missing in header format field: '{0}'", headerField);
}
else
{
//process header field type
headerLineType = headerField.Substring(0, separatorPosition).ToLowerInvariant();
headerLineContent = headerField.Substring(separatorPosition + 1).Trim(WhiteSpaceChars);
if (headerLineType == "" || headerLineContent == "")
{
//1 of the 2 parts missing, drop the line
return;
}
// add header line to headers
message.Headers.Add(headerLineType, headerLineContent);
//interpret if possible
switch (headerLineType)
{
case "bcc":
AddMailAddresses(headerLineContent, message.Bcc);
break;
case "cc":
AddMailAddresses(headerLineContent, message.CC);
break;
case "content-description":
message.ContentDescription = headerLineContent;
break;
case "content-disposition":
message.ContentDisposition = new ContentDisposition(headerLineContent);
break;
case "content-id":
message.ContentId = headerLineContent;
break;
case "content-transfer-encoding":
message.TransferType = headerLineContent;
message.ContentTransferEncoding = ConvertToTransferEncoding(headerLineContent);
break;
case "content-type":
message.SetContentTypeFields(headerLineContent);
break;
case "date":
message.DeliveryDate = ConvertToDateTime(headerLineContent);
break;
case "delivered-to":
message.DeliveredTo = ConvertToMailAddress(headerLineContent);
break;
case "from":
MailAddress address = ConvertToMailAddress(headerLineContent);
if (address != null)
{
message.From = address;
}
break;
case "message-id":
message.MessageId = headerLineContent;
break;
case "mime-version":
message.MimeVersion = headerLineContent;
//message.BodyEncoding = new Encoding();
break;
case "sender":
message.Sender = ConvertToMailAddress(headerLineContent);
break;
case "subject":
message.Subject = headerLineContent;
break;
case "received":
//throw mail routing information away
break;
case "reply-to":
message.ReplyToList.Add(ConvertToMailAddress(headerLineContent));
break;
case "return-path":
message.ReturnPath = ConvertToMailAddress(headerLineContent);
break;
case "to":
AddMailAddresses(headerLineContent, message.To);
break;
default:
message.UnknowHeaderlines.Add(headerField);
if (isCollectUnknowHeaderLines)
{
AllUnknowHeaderLines.Add(headerField);
}
break;
}
}
}
private MimeEntityReturnCode ProcessDelimitedBody(
RxMailMessage message,
string BoundaryStart,
string parentBoundaryStart,
string parentBoundaryEnd)
{
string response;
if (BoundaryStart.Trim() == parentBoundaryStart.Trim())
{
//Mime entity boundaries have to be unique
callGetEmailWarning("new boundary same as parent boundary: '{0}'", parentBoundaryStart);
//empty this message
while (readMultiLine(out response)) { }
return MimeEntityReturnCode.problem;
}
//
MimeEntityReturnCode ReturnCode;
do
{
//empty StringBuilder
MimeEntitySB.Length = 0;
RxMailMessage ChildPart = message.CreateChildEntity();
//recursively call MIME part processing
ReturnCode = ProcessMimeEntity(ChildPart, BoundaryStart);
if (ReturnCode == MimeEntityReturnCode.problem)
{
//it seems the received email doesn't follow the MIME specification. Stop here
return MimeEntityReturnCode.problem;
}
//add the newly found child MIME part to the parent
AddChildPartsToParent(ChildPart, message);
} while (ReturnCode != MimeEntityReturnCode.parentBoundaryEndFound);
//disregard all future lines until parent boundary is found or end of complete message
MimeEntityReturnCode boundaryMimeReturnCode;
bool hasParentBoundary = parentBoundaryStart.Length > 0;
while (readMultiLine(out response))
{
if (hasParentBoundary && parentBoundaryFound(response, parentBoundaryStart, parentBoundaryEnd, out boundaryMimeReturnCode))
{
return boundaryMimeReturnCode;
}
}
return MimeEntityReturnCode.bodyComplete;
}
/// <summary>
/// Add all attachments and alternative views from child to the parent
/// </summary>
private void AddChildPartsToParent(RxMailMessage child, RxMailMessage parent)
{
//add the child itself to the parent
parent.Entities.Add(child);
//add the alternative views of the child to the parent
if (child.AlternateViews != null)
{
foreach (AlternateView childView in child.AlternateViews)
{
parent.AlternateViews.Add(childView);
}
}
//add the body of the child as alternative view to parent
//this should be the last view attached here, because the POP 3 MIME client
//is supposed to display the last alternative view
if (child.MediaMainType == "text" && child.ContentStream != null &&
child.Parent.ContentType != null && child.Parent.ContentType.MediaType.ToLowerInvariant() == "multipart/alternative")
{
AlternateView thisAlternateView = new AlternateView(child.ContentStream);
thisAlternateView.ContentId = RemoveBrackets(child.ContentId);
thisAlternateView.ContentType = child.ContentType;
thisAlternateView.TransferEncoding = child.ContentTransferEncoding;
parent.AlternateViews.Add(thisAlternateView);
}
//add the attachments of the child to the parent
if (child.Attachments != null)
{
foreach (Attachment childAttachment in child.Attachments)
{
parent.Attachments.Add(childAttachment);
}
}
}
/// <summary>
/// Gets 1 email from POP3 server and processes it.
/// </summary>
/// <param name="MessageNo">Email Id to be fetched from POP3 server</param>
/// <param name="Message">decoded email</param>
/// <returns>false: no email received or email not properly formatted</returns>
public bool GetEmail(int MessageNo, out RxMailMessage Message)
{
Message = null;
//request email, send RETRieve command to POP3 server
if (!SendRetrCommand(MessageNo))
{
return false;
}
//prepare message, set defaults as specified in RFC 2046
//although they get normally overwritten, we have to make sure there are at least defaults
Message = new RxMailMessage();
Message.ContentTransferEncoding = TransferEncoding.SevenBit;
Message.TransferType = "7bit";
this.messageNo = MessageNo;
//raw email tracing
if (isGetRawEmail)
{
isTraceRawEmail = true;
if (RawEmailSB == null)
{
RawEmailSB = new StringBuilder(100000);
}
else
{
RawEmailSB.Length = 0;
}
}
//convert received email into RxMailMessage
MimeEntityReturnCode MessageMimeReturnCode = ProcessMimeEntity(Message, "");
if (isGetRawEmail)
{
//add raw email version to message
Message.RawContent = RawEmailSB.ToString();
isTraceRawEmail = false;
}
if (MessageMimeReturnCode == MimeEntityReturnCode.bodyComplete ||
MessageMimeReturnCode == MimeEntityReturnCode.parentBoundaryEndFound)
{
TraceFrom("email with {0} body chars received", Message.Body.Length);
return true;
}
return false;
}
