idmessagecodermime.pas

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{ Unit archived using Team Coherence                                   }
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{ $Log:  11673: IdMessageCoderMIME.pas
{
{   Rev 1.36    27.08.2004 22:03:58  Andreas Hausladen
{ speed optimization ("const" for string parameters)
}
{
{   Rev 1.35    8/15/04 5:41:00 PM  RLebeau
{ Updated GetAttachmentFilename() to handle cases where Outlook puts spaces
{ between "name=" and the filename.
{ 
{ Updated CheckAndSetType() to retreive the filename before checking the type. 
{ This helps to detect all file attachments better, including "form-data"
{ attachments
}
{
{   Rev 1.34    8/11/04 1:32:52 AM  RLebeau
{ Bug fix for TIdMessageDecoderMIME.GetAttachmentFilename()
}
{
{   Rev 1.33    8/10/04 1:41:48 PM  RLebeau
{ Misc. tweaks
}
{
    Rev 1.32    6/11/2004 9:38:22 AM  DSiders
  Added "Do not Localize" comments.
}
{
{   Rev 1.31    6/4/04 12:41:04 PM  RLebeau
{ ContentTransferEncoding bug fix
}
{
{   Rev 1.30    29/05/2004 21:23:56  CCostelloe
{ Added support for decoding attachments with a Content-Transfer-Encoding of
{ binary
}
{
{   Rev 1.29    2004.05.20 1:39:12 PM  czhower
{ Last of the IdStream updates
}
{
{   Rev 1.28    2004.05.20 11:36:56 AM  czhower
{ IdStreamVCL
}
{
{   Rev 1.27    2004.05.20 11:13:00 AM  czhower
{ More IdStream conversions
}
{
{   Rev 1.26    2004.05.19 3:06:40 PM  czhower
{ IdStream / .NET fix
}
{
{   Rev 1.25    16/05/2004 18:55:26  CCostelloe
{ New TIdText/TIdAttachment processing
}
{
{   Rev 1.24    23/04/2004 20:50:24  CCostelloe
{ Paths removed from attachment filenames and invalid Windows filename chars
{ weeded out
}
{
{   Rev 1.23    04/04/2004 17:44:56  CCostelloe
{ Bug fix
}
{
{   Rev 1.22    03/04/2004 20:27:22  CCostelloe
{ Fixed bug where code assumed Content-Type always contained a filename for the
{ attachment.
}
{
{   Rev 1.21    2004.02.03 5:44:04 PM  czhower
{ Name changes
}
{
{   Rev 1.20    1/31/2004 3:12:48 AM  JPMugaas
{ Removed dependancy on Math unit.  It isn't needed and is problematic in some
{ versions of Dlephi which don't include it.
}
{
{   Rev 1.19    1/22/2004 4:02:52 PM  SPerry
{ fixed set problems
}
{
{   Rev 1.18    16/01/2004 17:42:56  CCostelloe
{ Added support for BinHex 4.0 encoding
}
{
{   Rev 1.17    5/12/2003 9:18:26 AM  GGrieve
{ use WriteStringToStream
}
{
{   Rev 1.16    5/12/2003 12:31:16 AM  GGrieve
{ Fis WriteBuffer - can't be used in DotNet
}
{
    Rev 1.15    10/17/2003 12:40:20 AM  DSiders
  Added localization comments.
}
{
{   Rev 1.14    05/10/2003 16:41:54  CCostelloe
{ Restructured MIME boundary outputting
}
{
{   Rev 1.13    29/09/2003 13:07:48  CCostelloe
{ Second RandomRange replaced with Random
}
{
{   Rev 1.12    28/09/2003 22:56:30  CCostelloe
{ TIdMessageEncoderInfoMIME.InitializeHeaders now only sets ContentType if it
{ is ''
}
{
{   Rev 1.11    28/09/2003 21:06:52  CCostelloe
{ Recoded RandomRange to Random to suit D% and BCB5
}
{
{   Rev 1.10    26/09/2003 01:05:42  CCostelloe
{ Removed FIndyMultiPartAlternativeBoundary, IFndyMultiPartRelatedBoundary - no
{ longer needed.  Added support for ContentTransferEncoding '8bit'.  Changed
{ nested MIME decoding from finding boundary to finding 'multipart/'.
}
{
{   Rev 1.9    04/09/2003 20:46:38  CCostelloe
{ Added inclusion of =_ in boundary generation in
{ TIdMIMEBoundaryStrings.GenerateStrings
}
{
{   Rev 1.8    30/08/2003 18:39:58  CCostelloe
{ MIME boundaries changed to be random strings
}
{
{   Rev 1.7    07/08/2003 00:56:48  CCostelloe
{ ReadBody altered to allow lines over 16K (arises with long html parts)
}
{
{   Rev 1.6    2003.06.14 11:08:10 PM  czhower
{ AV fix
}
{
{   Rev 1.5    6/14/2003 02:46:42 PM  JPMugaas
{ Kudzu wanted the BeginDecode called after LDecoder was created and EndDecode
{ to be called just before LDecoder was destroyed.
}
{
    Rev 1.4    6/14/2003 1:14:12 PM  BGooijen
  fix for the bug where the attachments are empty
}
{
{   Rev 1.3    6/13/2003 07:58:46 AM  JPMugaas
{ Should now compile with new decoder design.
}
{
{   Rev 1.2    5/23/03 11:24:06 AM  RLebeau
{ Fixed a compiler error for previous changes
}
{
{   Rev 1.1    5/23/03 9:51:18 AM  RLebeau
{ Fixed bug where message body is parsed incorrectly when MIMEBoundary is empty.
}
{
{   Rev 1.0    11/13/2002 07:57:08 AM  JPMugaas
}
unit IdMessageCoderMIME;

{
  2003-Oct-04 Ciaran Costelloe
    Moved boundary out of InitializeHeaders into TIdMessage.GenerateHeader
}

// for all 3 to 4s:
//// TODO: Predict output sizes and presize outputs, then use move on
// presized outputs when possible, or presize only and reposition if stream

interface

uses
  Classes,
  IdMessageCoder, IdMessage, IdStream, IdStreamRandomAccess;

type
  TIdMessageDecoderMIME = class(TIdMessageDecoder)
  protected
    FFirstLine: string;
    FBodyEncoded: Boolean;
    FMIMEBoundary: string;
  public
    constructor Create(AOwner: TComponent); reintroduce; overload;
    constructor Create(AOwner: TComponent; const ALine: string); reintroduce; overload;
    function ReadBody(ADestStream: TIdStream;
      var VMsgEnd: Boolean): TIdMessageDecoder; override;
    procedure CheckAndSetType(AContentType, AContentDisposition: string);
    procedure ReadHeader; override;
    function GetAttachmentFilename(AContentType, AContentDisposition: string): string;
    function RemoveInvalidCharsFromFilename(const AFilename: string): string;
    //
    property MIMEBoundary: string read FMIMEBoundary write FMIMEBoundary;
    property BodyEncoded: Boolean read FBodyEncoded write FBodyEncoded;
  end;

  TIdMessageDecoderInfoMIME = class(TIdMessageDecoderInfo)
  public
    function CheckForStart(ASender: TIdMessage; const ALine: string): TIdMessageDecoder; override;
  end;

  TIdMessageEncoderMIME = class(TIdMessageEncoder)
  public
    procedure Encode(ASrc: TIdStreamRandomAccess; ADest: TIdStream); override;
  end;

  TIdMessageEncoderInfoMIME = class(TIdMessageEncoderInfo)
  public
    constructor Create; override;
    procedure InitializeHeaders(AMsg: TIdMessage); override;
  end;

  TIdMIMEBoundaryStrings = class
  private
    {CC2: After recoding SendBody et al, dont need FIndyMultiPartAlternativeBoundary
    or FIndyMultiPartRelatedBoundary.}
    FIndyMIMEBoundary: string;
    //FIndyMultiPartAlternativeBoundary: string;
    //FIndyMultiPartRelatedBoundary: string;
    procedure GenerateStrings;
  public
    function GenerateRandomChar: Char;
    function IndyMIMEBoundary: string;
    //function IndyMultiPartAlternativeBoundary: string;
    //function IndyMultiPartRelatedBoundary: string;
  end;

var
  //Note the following is created in the initialization section, so that the
  //overhead of boundary creation is only done at most once per session...
  IdMIMEBoundaryStrings: TIdMIMEBoundaryStrings;

const
  //NOTE: If you used IndyMIMEBoundary, just prefix it with "IdMIMEBoundaryStrings." now.
  //IndyMIMEBoundary                 = '=_NextPart_2rfkindysadvnqw3nerasdf'; {do not localize}
  //IndyMultiPartAlternativeBoundary = '=_NextPart_2altrfkindysadvnqw3nerasdf'; {do not localize}
  //IndyMultiPartRelatedBoundary     = '=_NextPart_2relrfksadvnqindyw3nerasdf'; {do not localize}
  MIMEGenericText = 'text/'; {do not localize}
  MIMEGenericMultiPart = 'multipart/'; {do not localize}
  MIME7Bit = '7bit'; {do not localize}
  {Per Microsoft KnowledgeBase article KB 177506, the following are the only Windows chars permitted:}
  ValidWindowsFilenameChars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890^&''@{}[],$=!-#()%.+~_'; {do not localize}

implementation

uses
  IdCoder, IdCoderMIME, IdGlobal, IdException, IdGlobalProtocols, IdResourceStrings,
  IdCoderQuotedPrintable, IdCoderBinHex4, SysUtils, IdCoderHeader;

{ TIdMIMEBoundaryStrings }
function TIdMIMEBoundaryStrings.GenerateRandomChar: Char;
var
  LOrd: integer;
  LFloat: Double;
begin
  {Allow only digits (ASCII 48-57), uppercase letters (65-90) and lowercase
  letters (97-122), which is 62 possible chars...}
  LFloat := (Random* 61) + 1.5;  //Gives us 1.5 to 62.5
  LOrd := Trunc(LFloat)+47;  //(1..62) -> (48..109)
  if LOrd > 83 then begin
    LOrd := LOrd + 13;  {Move into lowercase letter range}
  end else if LOrd > 57 then begin
    LOrd := LOrd + 7;  {Move into uppercase letter range}
  end;
  Result := Chr(LOrd);
end;

procedure TIdMIMEBoundaryStrings.GenerateStrings;
{This generates random MIME boundaries.  They are only generated once each time
a program containing this unit is run.}
var
  LN: integer;
  LFloat: Double;
begin
  {Generate a string 34 characters long (34 is a whim, not a requirement)...}
  FIndyMIMEBoundary := '1234567890123456789012345678901234';  {do not localize}
  Randomize;
  for LN := 1 to Length(FIndyMIMEBoundary) do begin
    FIndyMIMEBoundary[LN] := GenerateRandomChar;
  end;
  {CC2: RFC 2045 recommends including "=_" in the boundary, insert in random location...}
  //LN := RandomRange(1,Length(FIndyMIMEBoundary)-1);
  LFloat := (Random * (Length(FIndyMIMEBoundary)-2)) + 1.5;  //Gives us 1.5 to Length-0.5
  LN := Trunc(LFloat);  // 1 to Length-1 (we are inserting a 2-char string)
  FIndyMIMEBoundary[LN] := '=';
  FIndyMIMEBoundary[LN+1] := '_';
  {The Alternative boundary is the same with a random lowercase letter added...}
  //FIndyMultiPartAlternativeBoundary := FIndyMIMEBoundary + Chr(RandomRange(97,122));
  {The Related boundary is the same with a random uppercase letter added...}
  //FIndyMultiPartRelatedBoundary     := FIndyMultiPartAlternativeBoundary + Chr(RandomRange(65,90));
end;

function TIdMIMEBoundaryStrings.IndyMIMEBoundary: string;
begin
  if FIndyMIMEBoundary = '' then begin
    GenerateStrings;
  end;
  Result := FIndyMIMEBoundary;
end;
{
function TIdMIMEBoundaryStrings.IndyMultiPartAlternativeBoundary: string;
begin
  if FIndyMIMEBoundary = '' then begin
    GenerateStrings;
  end;
  Result := FIndyMultiPartAlternativeBoundary;
end;
}
{
function TIdMIMEBoundaryStrings.IndyMultiPartRelatedBoundary: string;
begin
  if FIndyMIMEBoundary = '' then begin
    GenerateStrings;
  end;
  Result := FIndyMultiPartRelatedBoundary;
end;
}
{ TIdMessageDecoderInfoMIME }
function TIdMessageDecoderInfoMIME.CheckForStart(ASender: TIdMessage;
 const ALine: string): TIdMessageDecoder;
begin
  if ASender.MIMEBoundary.Boundary <> '' then begin
    if TextIsSame(ALine, '--' + ASender.MIMEBoundary.Boundary) then begin    {Do not Localize}
      Result := TIdMessageDecoderMIME.Create(ASender);
    end else if TextIsSame(ASender.ContentTransferEncoding, 'base64') or    {Do not Localize}
      TextIsSame(ASender.ContentTransferEncoding, 'quoted-printable') then begin    {Do not Localize}
        Result := TIdMessageDecoderMIME.Create(ASender, ALine);
    end else begin
      Result := nil;
    end;
  end else begin
    Result := nil;
  end;
end;

{ TIdCoderMIME }

constructor TIdMessageDecoderMIME.Create(AOwner: TComponent);
begin
  inherited;
  FBodyEncoded := False;
  if AOwner is TIdMessage then begin
    FMIMEBoundary := TIdMessage(AOwner).MIMEBoundary.Boundary;
    {CC2: Check to see if this is an email of the type that is headers followed