/// <summary>
/// Extract the header part and body part of a message.<br/>
/// The headers are then parsed to a strongly typed <see cref="MessageHeader"/> object.
/// </summary>
/// <param name="fullRawMessage">The full message in bytes where header and body needs to be extracted from</param>
/// <param name="headers">The extracted header parts of the message</param>
/// <param name="body">The body part of the message</param>
/// <exception cref="ArgumentNullException">If <paramref name="fullRawMessage"/> is <see langword="null"/></exception>
public static void ExtractHeadersAndBody(byte[] fullRawMessage, out MessageHeader headers, out byte[] body)
{
if (fullRawMessage == null)
throw new ArgumentNullException("fullRawMessage");
// Find the end location of the headers
var endOfHeaderLocation = FindHeaderEndPosition(fullRawMessage);
// The headers are always in ASCII - therefore we can convert the header part into a string
// using US-ASCII encoding
//var headersString = Encoding.ASCII.GetString(fullRawMessage, 0, endOfHeaderLocation);
// MIME headers should aways be ASCII encoded, but sometimes they don't so we read then as UTF8.
// It should not make any difference if we do it this way because UTF-8 superseeds ASCII encoding
var headersString = Encoding.UTF8.GetString(fullRawMessage, 0, endOfHeaderLocation);
// Now parse the headers to a NameValueCollection
var headersUnparsedCollection = ExtractHeaders(headersString);
// Use the NameValueCollection to parse it into a strongly-typed MessageHeader header
headers = new MessageHeader(headersUnparsedCollection);
// Since we know where the headers end, we also know where the body is
// Copy the body part into the body parameter
body = new byte[fullRawMessage.Length - endOfHeaderLocation];
Array.Copy(fullRawMessage, endOfHeaderLocation, body, 0, body.Length);
}
/// <summary>
/// Figures out the filename of this message part.
/// <see cref="FileName"/> property.
/// </summary>
/// <param name="rawBody">The body that needs to be parsed</param>
/// <param name="headers">The headers that should be used from the message</param>
/// <param name="defaultName">The default filename to use, if no other could be found</param>
/// <returns>The filename found, or the default one if not such filename could be found in the headers</returns>
/// <exception cref="ArgumentNullException">if <paramref name="headers"/> is <see langword="null"/></exception>
private static string FindFileName(byte[] rawBody, MessageHeader headers, string defaultName)
{
if (headers == null)
throw new ArgumentNullException("headers");
if (headers.ContentDisposition != null && headers.ContentDisposition.FileName != null)
return FileManager.RemoveInvalidFileNameChars(headers.ContentDisposition.FileName);
var extensionFromContentType = string.Empty;
string contentTypeName = null;
if (headers.ContentType != null)
{
extensionFromContentType = MimeType.GetExtensionFromMimeType(headers.ContentType.MediaType);
contentTypeName = headers.ContentType.Name;
}
if (!string.IsNullOrEmpty(headers.ContentDescription))
return FileManager.RemoveInvalidFileNameChars(headers.ContentDescription + extensionFromContentType);
if (!string.IsNullOrEmpty(headers.Subject))
return FileManager.RemoveInvalidFileNameChars(headers.Subject) + extensionFromContentType;
if (extensionFromContentType.Equals(".eml", StringComparison.OrdinalIgnoreCase))
{
try
{
var message = new Message(rawBody);
if (message.Headers != null && !string.IsNullOrEmpty(message.Headers.Subject))
return FileManager.RemoveInvalidFileNameChars(message.Headers.Subject) + extensionFromContentType;
}
// ReSharper disable once EmptyGeneralCatchClause
catch { }
}
return !string.IsNullOrEmpty(contentTypeName)
? FileManager.RemoveInvalidFileNameChars(contentTypeName)
: FileManager.RemoveInvalidFileNameChars(defaultName + extensionFromContentType);
}
/// <summary>
/// Used to construct the topmost message part
/// </summary>
/// <param name="rawBody">The body that needs to be parsed</param>
/// <param name="headers">The headers that should be used from the message</param>
/// <exception cref="ArgumentNullException">If <paramref name="rawBody"/> or <paramref name="headers"/>
/// is <see langword="null"/></exception>
internal MessagePart(byte[] rawBody, MessageHeader headers)
{
if(rawBody == null)
throw new ArgumentNullException("rawBody");
if(headers == null)
throw new ArgumentNullException("headers");
ContentType = headers.ContentType;
ContentDescription = headers.ContentDescription;
ContentTransferEncoding = headers.ContentTransferEncoding;
ContentId = headers.ContentId;
ContentDisposition = headers.ContentDisposition;
FileName = FindFileName(rawBody, headers, LanguageConsts.NameLessFileName);
BodyEncoding = ParseBodyEncoding(ContentType.CharSet);
ParseBody(rawBody);
}
