/// <summary>
/// Decodes "encoded-word"'s from the specified text. For more information see RFC 2047.
/// </summary>
/// <param name="text">Text to decode.</param>
/// <returns>Returns decoded text.</returns>
public static string DecodeWords(string text)
{
if (text == null)
{
return(null);
}
/* RFC 2047 2. Syntax of encoded-words.
* An 'encoded-word' is defined by the following ABNF grammar. The
* notation of RFC 822 is used, with the exception that white space
* characters MUST NOT appear between components of an 'encoded-word'.
*
* encoded-word = "=?" charset "?" encoding "?" encoded-text "?="
* charset = token ; see section 3
* encoding = token ; see section 4
* token = 1*<Any CHAR except SPACE, CTLs, and especials>
* especials = "(" / ")" / "<" / ">" / "@" / "," / ";" / ":" / "
* <"> / "/" / "[" / "]" / "?" / "." / "="
* encoded-text = 1*<Any printable ASCII character other than "?" or SPACE>
* ; (but see "Use of encoded-words in message headers", section 5)
*
* Both 'encoding' and 'charset' names are case-independent. Thus the
* charset name "ISO-8859-1" is equivalent to "iso-8859-1", and the
* encoding named "Q" may be spelled either "Q" or "q".
*
* An 'encoded-word' may not be more than 75 characters long, including
* 'charset', 'encoding', 'encoded-text', and delimiters. If it is
* desirable to encode more text than will fit in an 'encoded-word' of
* 75 characters, multiple 'encoded-word's (separated by CRLF SPACE) may
* be used.
*
* IMPORTANT: 'encoded-word's are designed to be recognized as 'atom's
* by an RFC 822 parser. As a consequence, unencoded white space
* characters (such as SPACE and HTAB) are FORBIDDEN within an
* 'encoded-word'. For example, the character sequence
*
* =?iso-8859-1?q?this is some text?=
*
* would be parsed as four 'atom's, rather than as a single 'atom' (by
* an RFC 822 parser) or 'encoded-word' (by a parser which understands
* 'encoded-words'). The correct way to encode the string "this is some
* text" is to encode the SPACE characters as well, e.g.
*
* =?iso-8859-1?q?this=20is=20some=20text?=
*/
StringReader r = new StringReader(text);
StringBuilder retVal = new StringBuilder();
// We need to loop all words, if encoded word, decode it, othwerwise just append to return value.
bool lastIsEncodedWord = false;
while (r.Available > 0)
{
string whiteSpaces = r.ReadToFirstChar();
// Probably is encoded-word, we try to parse it.
if (r.StartsWith("=?") && r.SourceString.IndexOf("?=") > -1)
{
StringBuilder encodedWord = new StringBuilder();
string decodedWord = null;
try
{
// NOTE: We can't read encoded word and then split !!!, we need to read each part.
// Remove =?
encodedWord.Append(r.ReadSpecifiedLength(2));
// Read charset
string charset = r.QuotedReadToDelimiter('?');
encodedWord.Append(charset + "?");
// Read encoding
string encoding = r.QuotedReadToDelimiter('?');
encodedWord.Append(encoding + "?");
// Read text
string encodedText = r.QuotedReadToDelimiter('?');
encodedWord.Append(encodedText + "?");
// We must have remaining '=' here
if (r.StartsWith("="))
{
encodedWord.Append(r.ReadSpecifiedLength(1));
Encoding c = EncodingTools.GetEncodingByCodepageName(charset);
if (c != null)
{
if (encoding.ToLower() == "q")
{
decodedWord = Core.QDecode(c, encodedText);
}
else if (encoding.ToLower() == "b")
{
decodedWord =
c.GetString(Core.Base64Decode(Encoding.Default.GetBytes(encodedText)));
}
}
}
}
catch
{
// Not encoded-word or contains unknwon charset/encoding, so leave
// encoded-word as is.
}
/* RFC 2047 6.2.
* When displaying a particular header field that contains multiple
* 'encoded-word's, any 'linear-white-space' that separates a pair of
* adjacent 'encoded-word's is ignored. (This is to allow the use of
* multiple 'encoded-word's to represent long strings of unencoded text,
* without having to separate 'encoded-word's where spaces occur in the
* unencoded text.)
*/
if (!lastIsEncodedWord)
{
retVal.Append(whiteSpaces);
}
// Decoding failed for that encoded-word, leave encoded-word as is.
if (decodedWord == null)
{
retVal.Append(encodedWord.ToString());
}
// We deocded encoded-word successfully.
else
{
retVal.Append(decodedWord);
}
lastIsEncodedWord = true;
}
// Normal word.
else if (r.StartsWithWord())
{
retVal.Append(whiteSpaces + r.ReadWord(false));
lastIsEncodedWord = false;
}
// We have some separator or parenthesize.
else
{
retVal.Append(whiteSpaces + r.ReadSpecifiedLength(1));
}
}
return(retVal.ToString());
}
/// <summary>
/// Decodes "encoded-word"'s from the specified text. For more information see RFC 2047.
/// </summary>
/// <param name="text">Text to decode.</param>
/// <returns>Returns decoded text.</returns>
public static string DecodeWords(string text)
{
if (text == null)
{
return null;
}
/* RFC 2047 2. Syntax of encoded-words.
An 'encoded-word' is defined by the following ABNF grammar. The
notation of RFC 822 is used, with the exception that white space
characters MUST NOT appear between components of an 'encoded-word'.
encoded-word = "=?" charset "?" encoding "?" encoded-text "?="
charset = token ; see section 3
encoding = token ; see section 4
token = 1*<Any CHAR except SPACE, CTLs, and especials>
especials = "(" / ")" / "<" / ">" / "@" / "," / ";" / ":" / "
<"> / "/" / "[" / "]" / "?" / "." / "="
encoded-text = 1*<Any printable ASCII character other than "?" or SPACE>
; (but see "Use of encoded-words in message headers", section 5)
Both 'encoding' and 'charset' names are case-independent. Thus the
charset name "ISO-8859-1" is equivalent to "iso-8859-1", and the
encoding named "Q" may be spelled either "Q" or "q".
An 'encoded-word' may not be more than 75 characters long, including
'charset', 'encoding', 'encoded-text', and delimiters. If it is
desirable to encode more text than will fit in an 'encoded-word' of
75 characters, multiple 'encoded-word's (separated by CRLF SPACE) may
be used.
IMPORTANT: 'encoded-word's are designed to be recognized as 'atom's
by an RFC 822 parser. As a consequence, unencoded white space
characters (such as SPACE and HTAB) are FORBIDDEN within an
'encoded-word'. For example, the character sequence
=?iso-8859-1?q?this is some text?=
would be parsed as four 'atom's, rather than as a single 'atom' (by
an RFC 822 parser) or 'encoded-word' (by a parser which understands
'encoded-words'). The correct way to encode the string "this is some
text" is to encode the SPACE characters as well, e.g.
=?iso-8859-1?q?this=20is=20some=20text?=
*/
StringReader r = new StringReader(text);
StringBuilder retVal = new StringBuilder();
// We need to loop all words, if encoded word, decode it, othwerwise just append to return value.
bool lastIsEncodedWord = false;
while (r.Available > 0)
{
string whiteSpaces = r.ReadToFirstChar();
// Probably is encoded-word, we try to parse it.
if (r.StartsWith("=?") && r.SourceString.IndexOf("?=") > -1)
{
StringBuilder encodedWord = new StringBuilder();
string decodedWord = null;
try
{
// NOTE: We can't read encoded word and then split !!!, we need to read each part.
// Remove =?
encodedWord.Append(r.ReadSpecifiedLength(2));
// Read charset
string charset = r.QuotedReadToDelimiter('?');
encodedWord.Append(charset + "?");
// Read encoding
string encoding = r.QuotedReadToDelimiter('?');
encodedWord.Append(encoding + "?");
// Read text
string encodedText = r.QuotedReadToDelimiter('?');
encodedWord.Append(encodedText + "?");
// We must have remaining '=' here
if (r.StartsWith("="))
{
encodedWord.Append(r.ReadSpecifiedLength(1));
Encoding c = EncodingTools.GetEncodingByCodepageName(charset);
if (c != null)
{
if (encoding.ToLower() == "q")
{
decodedWord = Core.QDecode(c, encodedText);
}
else if (encoding.ToLower() == "b")
{
decodedWord =
c.GetString(Core.Base64Decode(Encoding.Default.GetBytes(encodedText)));
}
}
}
}
catch
{
// Not encoded-word or contains unknwon charset/encoding, so leave
// encoded-word as is.
}
/* RFC 2047 6.2.
When displaying a particular header field that contains multiple
'encoded-word's, any 'linear-white-space' that separates a pair of
adjacent 'encoded-word's is ignored. (This is to allow the use of
multiple 'encoded-word's to represent long strings of unencoded text,
without having to separate 'encoded-word's where spaces occur in the
unencoded text.)
*/
if (!lastIsEncodedWord)
{
retVal.Append(whiteSpaces);
}
// Decoding failed for that encoded-word, leave encoded-word as is.
if (decodedWord == null)
{
retVal.Append(encodedWord.ToString());
}
// We deocded encoded-word successfully.
else
{
retVal.Append(decodedWord);
}
lastIsEncodedWord = true;
}
// Normal word.
else if (r.StartsWithWord())
{
retVal.Append(whiteSpaces + r.ReadWord(false));
lastIsEncodedWord = false;
}
// We have some separator or parenthesize.
else
{
retVal.Append(whiteSpaces + r.ReadSpecifiedLength(1));
}
}
return retVal.ToString();
}
// TODO get rid of this method, only IMAP uses it
#region Methods
/// <summary>
/// Parses rfc 2822 datetime.
/// </summary>
/// <param name="date">Date string.</param>
/// <returns></returns>
public static DateTime ParseDate(string date)
{
/* Rfc 2822 3.3. Date and Time Specification.
* date-time = [ day-of-week "," ] date FWS time [CFWS]
* date = day month year
* time = hour ":" minute [ ":" second ] FWS zone
*/
/* IMAP date format.
* date-time = date FWS time [CFWS]
* date = day-month-year
* time = hour ":" minute [ ":" second ] FWS zone
*/
// zone = (( "+" / "-" ) 4DIGIT)
//--- Replace timezone constants -------//
/*
* UT -0000
* GMT -0000
* EDT -0400
* EST -0500
* CDT -0500
* CST -0600
* MDT -0600
* MST -0700
* PDT -0700
* PST -0800
* BST +0100 British Summer Time
*/
date = date.ToLower();
date = date.Replace("ut", "-0000");
date = date.Replace("gmt", "-0000");
date = date.Replace("edt", "-0400");
date = date.Replace("est", "-0500");
date = date.Replace("cdt", "-0500");
date = date.Replace("cst", "-0600");
date = date.Replace("mdt", "-0600");
date = date.Replace("mst", "-0700");
date = date.Replace("pdt", "-0700");
date = date.Replace("pst", "-0800");
date = date.Replace("bst", "+0100");
//----------------------------------------//
//--- Replace month constants ---//
date = date.Replace("jan", "01");
date = date.Replace("feb", "02");
date = date.Replace("mar", "03");
date = date.Replace("apr", "04");
date = date.Replace("may", "05");
date = date.Replace("jun", "06");
date = date.Replace("jul", "07");
date = date.Replace("aug", "08");
date = date.Replace("sep", "09");
date = date.Replace("oct", "10");
date = date.Replace("nov", "11");
date = date.Replace("dec", "12");
//-------------------------------//
// If date contains optional "day-of-week,", remove it
if (date.IndexOf(',') > -1)
{
date = date.Substring(date.IndexOf(',') + 1);
}
// Remove () from date. "Mon, 13 Oct 2003 20:50:57 +0300 (EEST)"
if (date.IndexOf(" (") > -1)
{
date = date.Substring(0, date.IndexOf(" ("));
}
int year = 1900;
int month = 1;
int day = 1;
int hour = -1;
int minute = -1;
int second = -1;
int zoneMinutes = -1;
StringReader s = new StringReader(date);
//--- Pase date --------------------------------------------------------------------//
try
{
day = Convert.ToInt32(s.ReadWord(true, new[] { '.', '-', ' ' }, true));
}
catch
{
throw new Exception("Invalid date value '" + date + "', invalid day value !");
}
try
{
month = Convert.ToInt32(s.ReadWord(true, new[] { '.', '-', ' ' }, true));
}
catch
{
throw new Exception("Invalid date value '" + date + "', invalid month value !");
}
try
{
year = Convert.ToInt32(s.ReadWord(true, new[] { '.', '-', ' ' }, true));
}
catch
{
throw new Exception("Invalid date value '" + date + "', invalid year value !");
}
//----------------------------------------------------------------------------------//
//--- Parse time -------------------------------------------------------------------//
// Time is optional, so parse it if its included.
if (s.Available > 0)
{
try
{
hour = Convert.ToInt32(s.ReadWord(true, new[] { ':' }, true));
}
catch
{
throw new Exception("Invalid date value '" + date + "', invalid hour value !");
}
try
{
minute = Convert.ToInt32(s.ReadWord(true, new[] { ':' }, false));
}
catch
{
throw new Exception("Invalid date value '" + date + "', invalid minute value !");
}
s.ReadToFirstChar();
if (s.StartsWith(":"))
{
s.ReadSpecifiedLength(1);
try
{
string secondString = s.ReadWord(true, new[] { ' ' }, true);
// Milli seconds specified, remove them.
if (secondString.IndexOf('.') > -1)
{
secondString = secondString.Substring(0, secondString.IndexOf('.'));
}
second = Convert.ToInt32(secondString);
}
catch
{
throw new Exception("Invalid date value '" + date + "', invalid second value !");
}
}
s.ReadToFirstChar();
if (s.Available > 3)
{
string timezone = s.SourceString.Replace(":", "");
if (timezone.StartsWith("+") || timezone.StartsWith("-"))
{
bool utc_add_time = timezone.StartsWith("+");
// Remove +/- sign
timezone = timezone.Substring(1);
// padd time zone to 4 symbol. For example 200, will be 0200.
while (timezone.Length < 4)
{
timezone = "0" + timezone;
}
try
{
// time zone format hours|minutes
int h = Convert.ToInt32(timezone.Substring(0, 2));
int m = Convert.ToInt32(timezone.Substring(2));
if (utc_add_time)
{
zoneMinutes = 0 - ((h * 60) + m);
}
else
{
zoneMinutes = (h * 60) + m;
}
}
catch
{
// Just skip time zone, if can't parse
}
}
}
}
//---------------------------------------------------------------------------------//
// Convert time to UTC
if (hour != -1 && minute != -1 && second != -1)
{
DateTime d = new DateTime(year, month, day, hour, minute, second).AddMinutes(zoneMinutes);
return
(new DateTime(d.Year, d.Month, d.Day, d.Hour, d.Minute, d.Second, DateTimeKind.Utc).
ToLocalTime());
}
else
{
return(new DateTime(year, month, day));
}
}
// TODO get rid of this method, only IMAP uses it
#region Methods
/// <summary>
/// Parses rfc 2822 datetime.
/// </summary>
/// <param name="date">Date string.</param>
/// <returns></returns>
public static DateTime ParseDate(string date)
{
/* Rfc 2822 3.3. Date and Time Specification.
date-time = [ day-of-week "," ] date FWS time [CFWS]
date = day month year
time = hour ":" minute [ ":" second ] FWS zone
*/
/* IMAP date format.
date-time = date FWS time [CFWS]
date = day-month-year
time = hour ":" minute [ ":" second ] FWS zone
*/
// zone = (( "+" / "-" ) 4DIGIT)
//--- Replace timezone constants -------//
/*
UT -0000
GMT -0000
EDT -0400
EST -0500
CDT -0500
CST -0600
MDT -0600
MST -0700
PDT -0700
PST -0800
BST +0100 British Summer Time
*/
date = date.ToLower();
date = date.Replace("ut", "-0000");
date = date.Replace("gmt", "-0000");
date = date.Replace("edt", "-0400");
date = date.Replace("est", "-0500");
date = date.Replace("cdt", "-0500");
date = date.Replace("cst", "-0600");
date = date.Replace("mdt", "-0600");
date = date.Replace("mst", "-0700");
date = date.Replace("pdt", "-0700");
date = date.Replace("pst", "-0800");
date = date.Replace("bst", "+0100");
//----------------------------------------//
//--- Replace month constants ---//
date = date.Replace("jan", "01");
date = date.Replace("feb", "02");
date = date.Replace("mar", "03");
date = date.Replace("apr", "04");
date = date.Replace("may", "05");
date = date.Replace("jun", "06");
date = date.Replace("jul", "07");
date = date.Replace("aug", "08");
date = date.Replace("sep", "09");
date = date.Replace("oct", "10");
date = date.Replace("nov", "11");
date = date.Replace("dec", "12");
//-------------------------------//
// If date contains optional "day-of-week,", remove it
if (date.IndexOf(',') > -1)
{
date = date.Substring(date.IndexOf(',') + 1);
}
// Remove () from date. "Mon, 13 Oct 2003 20:50:57 +0300 (EEST)"
if (date.IndexOf(" (") > -1)
{
date = date.Substring(0, date.IndexOf(" ("));
}
int year = 1900;
int month = 1;
int day = 1;
int hour = -1;
int minute = -1;
int second = -1;
int zoneMinutes = -1;
StringReader s = new StringReader(date);
//--- Pase date --------------------------------------------------------------------//
try
{
day = Convert.ToInt32(s.ReadWord(true, new[] {'.', '-', ' '}, true));
}
catch
{
throw new Exception("Invalid date value '" + date + "', invalid day value !");
}
try
{
month = Convert.ToInt32(s.ReadWord(true, new[] {'.', '-', ' '}, true));
}
catch
{
throw new Exception("Invalid date value '" + date + "', invalid month value !");
}
try
{
year = Convert.ToInt32(s.ReadWord(true, new[] {'.', '-', ' '}, true));
}
catch
{
throw new Exception("Invalid date value '" + date + "', invalid year value !");
}
//----------------------------------------------------------------------------------//
//--- Parse time -------------------------------------------------------------------//
// Time is optional, so parse it if its included.
if (s.Available > 0)
{
try
{
hour = Convert.ToInt32(s.ReadWord(true, new[] {':'}, true));
}
catch
{
throw new Exception("Invalid date value '" + date + "', invalid hour value !");
}
try
{
minute = Convert.ToInt32(s.ReadWord(true, new[] {':'}, false));
}
catch
{
throw new Exception("Invalid date value '" + date + "', invalid minute value !");
}
s.ReadToFirstChar();
if (s.StartsWith(":"))
{
s.ReadSpecifiedLength(1);
try
{
string secondString = s.ReadWord(true, new[] {' '}, true);
// Milli seconds specified, remove them.
if (secondString.IndexOf('.') > -1)
{
secondString = secondString.Substring(0, secondString.IndexOf('.'));
}
second = Convert.ToInt32(secondString);
}
catch
{
throw new Exception("Invalid date value '" + date + "', invalid second value !");
}
}
s.ReadToFirstChar();
if (s.Available > 3)
{
string timezone = s.SourceString.Replace(":", "");
if (timezone.StartsWith("+") || timezone.StartsWith("-"))
{
bool utc_add_time = timezone.StartsWith("+");
// Remove +/- sign
timezone = timezone.Substring(1);
// padd time zone to 4 symbol. For example 200, will be 0200.
while (timezone.Length < 4)
{
timezone = "0" + timezone;
}
try
{
// time zone format hours|minutes
int h = Convert.ToInt32(timezone.Substring(0, 2));
int m = Convert.ToInt32(timezone.Substring(2));
if (utc_add_time)
{
zoneMinutes = 0 - ((h*60) + m);
}
else
{
zoneMinutes = (h*60) + m;
}
}
catch
{
// Just skip time zone, if can't parse
}
}
}
}
//---------------------------------------------------------------------------------//
// Convert time to UTC
if (hour != -1 && minute != -1 && second != -1)
{
DateTime d = new DateTime(year, month, day, hour, minute, second).AddMinutes(zoneMinutes);
return
new DateTime(d.Year, d.Month, d.Day, d.Hour, d.Minute, d.Second, DateTimeKind.Utc).
ToLocalTime();
}
else
{
return new DateTime(year, month, day);
}
}