Code:

function DateTimeToRfcTime(

dt: TDateTime;

iDiff: integer;

blnGMT: boolean = false): string;

{*

Explanation:

iDiff is the local offset to GMT in minutes

if blnGMT then Result is UNC time else local time

e.g. local time zone: ET = GMT - 5hr = -300 minutes

   dt is TDateTime of 3 Jan 2001 5:45am

     blnGMT = true  -> Result = 'Wed, 03 Jan 2001 05:45:00 GMT'

     blnGMT = false -> Result = 'Wed, 03 Jan 2001 05:45:00 -0500'

*}

const

Weekday: array[1..7] of string =

('Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat');

Month: array[1..12] of string = (

   'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',

   'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec');

var

iDummy: Word;

iYear: Word;

iMonth: Word;

iDay: Word;

iHour: Word;

iMinute: Word;

iSecond: Word;

strZone: string;

begin

if blnGMT then

begin

   dt := dt - iDiff / 1440;

   strZone := 'GMT';

end

else

begin

   iDiff := (iDiff div 60) * 100 + (iDiff mod 60);

   if iDiff < 0 then

     strZone := Format('-%.4d', [-iDiff])

   else

     strZone := Format('+%.4d', [iDiff]);

end;

DecodeDate(dt, iYear, iMonth, iDay);

DecodeTime(dt, iHour, iMinute, iSecond, iDummy);

Result := Format('%s, %.2d %s %4d %.2d:%.2d:%.2d %s', [

   Weekday[DayOfWeek(dt)], iDay, Month[iMonth], iYear,

     iHour, iMinute, iSecond, strZone]);

end;

function RfcTimeToDateTime(

strTime: string;

blnGMT: boolean = true): TDateTime;

{*

Explanation:

if blnGMT then Result is UNC time else local time

e.g. local time zone: ET = GMT - 5hr = -0500

   strTime = 'Wed, 03 Jan 2001 05:45:00 -0500'

     blnGMT = true  -> FormatDateTime('...', Result) = '03.01.2001 10:45:00'

     blnGMT = false -> FormatDateTime('...', Result) = '03.01.2001 05:45:00'

*}

const

wd = 'sun#mon#tue#wed#thu#fri#sat';

month = 'janfebmaraprmayjunjulaugsepoctnovdec';

var

s: string;

dd: Word;

mm: Word;

yy: Word;

hh: Word;

nn: Word;

ss: Word;

begin

s := LowerCase(Copy(strTime, 1, 3));

if Pos(s, wd) > 0 then

   Delete(strTime, 1, Pos(' ', strTime));

s := Trim(Copy(strTime, 1, Pos(' ', strTime)));

Delete(strTime, 1, Length(s) + 1);

dd := StrToIntDef(s, 0);

s := LowerCase(Copy(strTime, 1, 3));

Delete(strTime, 1, 4);

mm := (Pos(s, month) div 3) + 1;

s := Copy(strTime, 1, 4);

Delete(strTime, 1, 5);

yy := StrToIntDef(s, 0);

Result := EncodeDate(yy, mm, dd);

s := strTime[1] + strTime[2];

hh := StrToIntDef(strTime[1] + strTime[2], 0);

nn := StrToIntDef(strTime[4] + strTime[5], 0);

ss := StrToIntDef(strTime[7] + strTime[8], 0);

Delete(strTime, 1, 9);

Result := Result + EncodeTime(hh, nn, ss, 0);

if (CompareText(strTime, 'gmt') <> 0) and blnGMT then

begin

   hh := StrToIntDef(strTime[2] + strTime[3], 0);

   nn := StrToIntDef(strTime[4] + strTime[5], 0);

   if strTime[1] = '+' then

     Result := Result - EncodeTime(hh, nn, 0, 0)

   else

     Result := Result + EncodeTime(hh, nn, 0, 0);

end;

end;

Code:

function RFC1123ToDateTime(Date: string): TDateTime;

var

day, month, year: Integer;

strMonth: string;

Hour, Minute, Second: Integer;

begin

try

   day      := StrToInt(Copy(Date, 6, 2));

   strMonth := Copy(Date, 9, 3);

   if strMonth = 'Jan' then month := 1

   else if strMonth = 'Feb' then month := 2

   else if strMonth = 'Mar' then month := 3

   else if strMonth = 'Apr' then month := 4

   else if strMonth = 'May' then month := 5

   else if strMonth = 'Jun' then month := 6

   else if strMonth = 'Jul' then month := 7

   else if strMonth = 'Aug' then month := 8

   else if strMonth = 'Sep' then month := 9

   else if strMonth = 'Oct' then month := 10

   else if strMonth = 'Nov' then month := 11

   else if strMonth = 'Dec' then month := 12;

   year   := StrToInt(Copy(Date, 13, 4));

   hour   := StrToInt(Copy(Date, 18, 2));

   minute := StrToInt(Copy(Date, 21, 2));

   second := StrToInt(Copy(Date, 24, 2));

   Result := 0;

   Result := EncodeTime(hour, minute, second, 0);

   Result := Result + EncodeDate(year, month, day);

except

   Result := now;

end;

end;

function DateTimeToRFC1123(aDate: TDateTime): string;

const

StrWeekDay: string = 'MonTueWedThuFriSatSun';

StrMonth: string = 'JanFebMarAprMayJunJulAugSepOctNovDec';

var

Year, Month, Day: Word;

Hour, Min, Sec, MSec: Word;

DayOfWeek: Word;

begin

DecodeDate(aDate, Year, Month, Day);

DecodeTime(aDate, Hour, Min, Sec, MSec);

DayOfWeek := ((Trunc(aDate) - 2) mod 7);

Result    := Copy(StrWeekDay, 1 + DayOfWeek * 3, 3) + ', ' +

   Format('%2.2d %s %4.4d %2.2d:%2.2d:%2.2d',

   [Day, Copy(StrMonth, 1 + 3 * (Month - 1), 3),

   Year, Hour, Min, Sec]);

end;