How to send an email with a calendar request (content type: text/calendar)

Question

I have tried to embed the icalendar code in a email to be sent via indy with a content type text/calendar but it just hangs on the encoding of the email when I add as an attachment it just arrives as an attachment and does not prompt as other calendar request do. Has any one got example code of how to do calendar requests via indy?

Answer 1

@David, the email client will recognize as a calendar request the attachment if you set the property to ContentType:='text/calendar', see this link for the iCalendar format Specification

see this sample code (tested en Delphi 2010)

program SendMailWithCalendarRequest;
{$APPTYPE CONSOLE}


uses
  IdSMTP,
  Classes,
  DateUtils,
  IdAttachmentFile,
  IdMessage,
  SysUtils;

 procedure SendCalendarRequest;
 var
  SMTP        : TIdSMTP;
  MailMessage : TIdMessage;
  Calendar    : TStrings;
  CalendarFile: String;
  Attachment  : TIdAttachmentFile;
  SenderMail  : String;
 begin
    SenderMail:='[email protected]';
    CalendarFile:=ExtractFilePath(ParamStr(0))+'\appmnt.vcs';
    Calendar:=TStringList.Create;
    try
        Calendar.Add('BEGIN:VCALENDAR');
        Calendar.Add('VERSION:1.0');
        Calendar.Add('BEGIN:VEVENT');
        Calendar.Add('ORGANIZER:MAILTO:'+SenderMail);
        Calendar.Add('DTStart:'+FormatDateTime('YYYY-DD-DD',Now));
        Calendar.Add('DTEnd:'+FormatDateTime('YYYY-DD-DD',  Tomorrow));
        Calendar.Add('Location;ENCODING=QUOTED-PRINTABLE: My home');
        Calendar.Add('UID:'+FormatDateTime('YYYY-DD-DD',Now)+FormatDateTime('YYYY-DD-DD',Tomorrow));
        Calendar.Add('SUMMARY:Appointment Reminder');
        Calendar.Add('DESCRIPTION:Test message');
        Calendar.Add('PRIORITY:5');
        Calendar.Add('END:VEVENT');
        Calendar.Add('END:VCALENDAR');
        Calendar.SaveToFile(CalendarFile);
    finally
    Calendar.Free;
    end;

   SMTP:= TIdSMTP.Create(nil);
   MailMessage := TIdMessage.Create(nil);
   try
     SMTP.Host := 'smtp.mailserver.com';
     SMTP.Port := 25;
     SMTP.Username:='the account';
     SMTP.Password:='the password';
     SMTP.AuthType:=satDefault;
     MailMessage.From.Address := SenderMail;
     MailMessage.Recipients.EMailAddresses := 'the Recipient';
     MailMessage.Subject   := 'Send calendar';
     MailMessage.Body.Text := '';
     Attachment:=TIdAttachmentFile.Create(MailMessage.MessageParts, CalendarFile) ;
     Attachment.ContentType:='text/calendar';//set the content type to text/calendar
     try
       try
         SMTP.Connect;
         SMTP.Send(MailMessage) ;
         Writeln('OK')
       except on E:Exception do
         Writeln(0, 'ERROR: ' + E.Message) ;
       end;
     finally
       if SMTP.Connected then SMTP.Disconnect;
     end;
   finally
    SMTP.Free;
    MailMessage.Free;
   end;

 end;

begin
  try
    SendCalendarRequest;
    readln;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.