/// <summary>
/// Parses headers from message or mime entry.
/// </summary>
/// <param name="entryStrm">Stream from where to read headers.</param>
/// <returns>Returns header lines.</returns>
public static string ParseHeaders(Stream entryStrm)
{
/* Rfc 2822 3.1. GENERAL DESCRIPTION
* A message consists of header fields and, optionally, a body.
* The body is simply a sequence of lines containing ASCII charac-
* ters. It is separated from the headers by a null line (i.e., a
* line with nothing preceding the CRLF).
*/
byte[] crlf = new byte[] { (byte)'\r', (byte)'\n' };
MemoryStream msHeaders = new MemoryStream();
StreamLineReader r = new StreamLineReader(entryStrm);
byte[] lineData = r.ReadLine();
while (lineData != null)
{
if (lineData.Length == 0)
{
break;
}
msHeaders.Write(lineData, 0, lineData.Length);
msHeaders.Write(crlf, 0, crlf.Length);
lineData = r.ReadLine();
}
return(System.Text.Encoding.Default.GetString(msHeaders.ToArray()));
}
/// <summary>
/// Parses header fields from stream. Stream position stays where header reading ends.
/// </summary>
/// <param name="stream">Stream from where to parse.</param>
public void Parse(Stream stream)
{
/* Rfc 2822 2.2 Header Fields
* Header fields are lines composed of a field name, followed by a colon
* (":"), followed by a field body, and terminated by CRLF. A field
* name MUST be composed of printable US-ASCII characters (i.e.,
* characters that have values between 33 and 126, inclusive), except
* colon. A field body may be composed of any US-ASCII characters,
* except for CR and LF. However, a field body may contain CRLF when
* used in header "folding" and "unfolding" as described in section
* 2.2.3. All field bodies MUST conform to the syntax described in
* sections 3 and 4 of this standard.
*
* Rfc 2822 2.2.3 Long Header Fields
* The process of moving from this folded multiple-line representation
* of a header field to its single line representation is called
* "unfolding". Unfolding is accomplished by simply removing any CRLF
* that is immediately followed by WSP. Each header field should be
* treated in its unfolded form for further syntactic and semantic
* evaluation.
*
* Example:
* Subject: aaaaa<CRLF>
* <TAB or SP>aaaaa<CRLF>
*/
m_pHeaderFields.Clear();
StreamLineReader r = new StreamLineReader(stream);
string line = r.ReadLineString();
while (line != null)
{
// End of header reached
if (line == "")
{
break;
}
// Store current header line and read next. We need to read 1 header line to ahead,
// because of multiline header fields.
string headerField = line;
line = r.ReadLineString();
// See if header field is multiline. See comment above.
while (line != null && (line.StartsWith("\t") || line.StartsWith(" ")))
{
headerField += line;
line = r.ReadLineString();
}
string[] name_value = headerField.Split(new char[] { ':' }, 2);
// There must be header field name and value, otherwise invalid header field
if (name_value.Length == 2)
{
Add(name_value[0] + ":", Core.CanonicalDecode(name_value[1].Trim()));
}
}
}
/// <summary>
/// Does period handling.
/// </summary>
/// <param name="strm">Input stream.</param>
/// <param name="add_Remove">If true add periods, else removes periods.</param>
/// <param name="setStrmPosTo0">If true sets stream position to 0.</param>
/// <returns></returns>
public static MemoryStream DoPeriodHandling(Stream strm, bool add_Remove, bool setStrmPosTo0)
{
MemoryStream replyData = new MemoryStream();
byte[] crlf = new byte[] { (byte)'\r', (byte)'\n' };
if (setStrmPosTo0)
{
strm.Position = 0;
}
StreamLineReader r = new StreamLineReader(strm);
byte[] line = r.ReadLine();
// Loop through all lines
while (line != null)
{
if (line.Length > 0)
{
if (line[0] == (byte)'.')
{
/* Add period Rfc 2821 4.5.2
* - Before sending a line of mail text, the SMTP client checks the
* first character of the line. If it is a period, one additional
* period is inserted at the beginning of the line.
*/
if (add_Remove)
{
replyData.WriteByte((byte)'.');
replyData.Write(line, 0, line.Length);
}
/* Remove period Rfc 2821 4.5.2
* If the first character is a period , the first characteris deleted.
*/
else
{
replyData.Write(line, 1, line.Length - 1);
}
}
else
{
replyData.Write(line, 0, line.Length);
}
}
replyData.Write(crlf, 0, crlf.Length);
// Read next line
line = r.ReadLine();
}
replyData.Position = 0;
return(replyData);
}
/// <summary>
/// Scans invalid CR or LF combination in stream. Returns true if contains invalid CR or LF combination.
/// </summary>
/// <param name="strm">Stream which to check.</param>
/// <returns>Returns true if contains invalid CR or LF combination.</returns>
public static bool ScanInvalid_CR_or_LF(Stream strm)
{
StreamLineReader lineReader = new StreamLineReader(strm);
byte[] line = lineReader.ReadLine();
while (line != null)
{
foreach (byte b in line)
{
// Contains CR or LF. It cannot conatian such sumbols, because CR must be paired with LF
// and we currently reading lines with CRLF combination.
if (b == 10 || b == 13)
{
return(true);
}
}
line = lineReader.ReadLine();
}
return(false);
}
