/// <summary>
/// Parses the supplied <paramref name="lines"/> into constituent <see cref="MimePart"/> instances
/// </summary>
/// <remarks>
/// This is the main parser interface. The <see cref="MimePart"/> instances expected to be returned are <see cref="Header"/> (one for each header), and <see cref="Body"/>
/// </remarks>
/// <param name="lines">The enumeration of <see cref="StringSegment"/> lines to parse</param>
/// <returns>An enumeration of the constituent <see cref="MimePart"/> instances parsed from the <paramref name="lines"/></returns>
public static IEnumerable <MimePart> ReadMimeParts(IEnumerable <StringSegment> lines)
{
if (lines == null)
{
throw new ArgumentNullException("lines");
}
MimePartType expectedPartType = MimePartType.Header;
Header header = null;
Body body = null;
foreach (StringSegment line in lines)
{
switch (expectedPartType)
{
default:
throw new MimeException(MimeError.Unexpected);
case MimePartType.Header:
if (line.IsEmpty)
{
if (header != null)
{
yield return(header);
header = null;
}
yield return(new MimePart(MimePartType.HeaderBoundary, line));
//
// Done with the header section. Onto the Body
//
expectedPartType = MimePartType.Body;
break;
}
if (MimeStandard.IsWhitespace(line[0]))
{
// Line folding. This line belongs to the current header
if (header == null)
{
throw new MimeException(MimeError.InvalidHeader);
}
header.AppendSourceText(line);
break;
}
if (header != null)
{
yield return(header);
}
header = new Header(line);
break;
case MimePartType.Body:
if (body == null)
{
body = new Body(line);
}
else
{
body.AppendSourceText(line);
}
break;
}
}
if (header != null)
{
yield return(header);
}
if (body != null)
{
yield return(body);
}
}
/// <summary>
/// Parses set of <see cref="StringSegment"/> supplying the individual lines of a <c>multipart</c> body, returning contituent parts.
/// </summary>
/// <param name="bodyLines">The <c>multipart</c> body lines</param>
/// <param name="boundary">The <c>multipart</c> boundary string</param>
/// <returns>The constituent body parts.</returns>
public static IEnumerable <MimePart> ReadBodyParts(IEnumerable <StringSegment> bodyLines, string boundary)
{
if (bodyLines == null)
{
throw new ArgumentNullException("bodyLines");
}
if (string.IsNullOrEmpty(boundary))
{
throw new MimeException(MimeError.MissingBoundarySeparator);
}
IEnumerator <StringSegment> lineEnumerator = bodyLines.GetEnumerator();
StringSegment part = StringSegment.Null;
StringSegment prevLine = StringSegment.Null;
MimePartType expectedPart = MimePartType.BodyPrologue;
//
// As per the Multipart Spec:
// The boundary delimiter is actually CRLF--boundary
// So we must maintain a stack (prevLine)..
//
while (expectedPart != MimePartType.BodyEpilogue && lineEnumerator.MoveNext())
{
StringSegment line = lineEnumerator.Current;
if (IsBoundary(line, boundary))
{
if (!part.IsNull)
{
part.Union(prevLine);
}
//
// When we hit a boundary, we yield the part we've collected so far
//
MimePartType partType = expectedPart;
switch (expectedPart)
{
default:
throw new MimeException(MimeError.InvalidBodySubpart);
case MimePartType.BodyPrologue:
expectedPart = MimePartType.BodyPart;
break;
case MimePartType.BodyPart:
if (IsBoundaryEnd(line))
{
expectedPart = MimePartType.BodyEpilogue;
}
break;
}
if (!part.IsNull)
{
yield return(new MimePart(partType, part));
}
prevLine = StringSegment.Null;
part = StringSegment.Null;
}
else
{
if (!prevLine.IsNull)
{
part.Union(prevLine);
}
prevLine = line;
}
}
if (expectedPart != MimePartType.BodyEpilogue)
{
throw new MimeException(MimeError.InvalidBodySubpart);
}
// Epilogue
part = StringSegment.Null;
while (lineEnumerator.MoveNext())
{
part.Union(lineEnumerator.Current);
}
if (!part.IsEmpty)
{
yield return(new MimePart(MimePartType.BodyEpilogue, part));
}
}
