Enjoy Email with Indy 10 and DELPHI
I am using the following code to calculate msg. content (body / lines) of E-mail received with INDY 10 components
function LinesFromMsg(aMsg: TIdMessage): TStrings;
var
i: Integer;
begin
for i := 0 to aMsg.MessageParts.AttachmentCount-1 do
begin
if (amsg.MessageParts.Items[i].ContentType ='HTML') then
begin
if (amsg.MessageParts.Items[i] is Tidtext) then
Result := TidText(amsg.MessageParts.Items[i]).body;
end;
end;
end;
regarding this code I have 2 questions:
a) is this the correct way to find the Tlines part in an arbitration message? (consider the guidelines provided in INDY 10 EMAIL MSG PARTS )
b) Where can I find a manual on all Contenttype string values?
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The correct value ContentType
to search for is text/html
. Use the Indy function IsHeaderMediaType()
to test it, as the value ContentType
may have additional attributes associated with it that your comparison should ignore.
You also need to take into account TIdMessage.ContentType
, as HTML emails cannot be MIME encoded and therefore not use the TIdMessage.MessageParts collection at all.
Finally, the loop must use a property MessageParts.Count
instead of a property MessageParts.AttachmentsCount
.
Try the following:
function HTMLFromMsg(aMsg: TIdMessage): TStrings;
var
i: Integer;
Part: TIdMessagePart;
begin
Result := nil;
if IsHeaderMediaType(aMsg.ContentType, 'text/html') then
begin
Result := aMsg.Body;
Exit;
end;
for i := 0 to aMsg.MessageParts.Count-1 do
begin
Part := aMsg.MessageParts.Items[i];
if (Part is TIdText) and IsHeaderMediaType(Part.ContentType, 'text/html') then
begin
Result := TIdText(Part).Body;
Exit;
end;
end;
end;
With that said, this is not technically the correct way to handle MIME. Officially, the intended reader should loop backward through the MIME parts as they are ordered from the simplest form down to the most complex form. This way you go back and forth, considering the MIME layout, looking for the most complex shape you can support. Something else similar (untested):
procedure DisplayPlainText(Body: TStrings);
begin
// display plain text as needed...
end;
procedure DisplayHTML(Body: TStrings);
begin
// display html as needed...
end;
procedure DisplayMultiPartAlternative(aMsg: TIdMessage; aParentIndex, aLastIndex: Integer);
var
Part: TIdMessagePart;
i: Integer:
begin
for i := aLastIndex-1 downto aParentIndex+1 do
begin
Part := aMsg.MessageParts.Items[i];
if (Part.ParentPart = aParentIndex) and (Part is TIdText) then
begin
if IsHeaderMediaType(Part.ContentType, 'text/html') then
begin
DisplayHTML(TIdText(Part).Body);
Exit;
end;
if IsHeaderMediaType(Part.ContentType, 'text/plain') then
begin
DisplayPlain(TIdText(Part).Body);
Exit;
end;
end;
end;
// nothing supported to display...
end;
procedure DisplayMultiPartMixed(aMsg: TIdMessage; aParentIndex, aLastIndex: Integer);
var
Part: TIdMessagePart;
i: Integer;
begin
for i := aLastIndex-1 downto aParentIndex+1 do
begin
Part := aMsg.MessageParts.Items[i];
if (Part.ParentPart = aParentIndex) and (Part is TIdText) then
begin
if IsHeaderMediaType(Part.ContentType, 'multipart/alternative') then
begin
DisplayMultiPartAlternative(aMsg, ParentPart.Index, aLastIndex);
Exit;
end;
if IsHeaderMediaType(ParentPart.ContentType, 'text/html') then
begin
DisplayHTML(TIdText(Part).Body);
Exit;
end;
if IsHeaderMediaType(Part.ContentType, 'text/plain') then
begin
DisplayHTML(TIdText(Part).Body);
Exit;
end;
aLastIndex := i;
end;
// nothing supported to display...
end;
procedure DisplayMsg(aMsg: TIdMessage);
var
ContentType: string;
begin
ContentType := ExtractHeaderMediaType(aMsg.ContentType);
case PosInStrArray(ContentType, ['multipart/mixed', 'multipart/alternative', 'text/html', 'text/plain'], False) of
0: begin
DisplayMultiPartAlternative(aMsg, -1, aMsg.MessageParts.Count);
Exit;
end;
1: begin
DisplayMultiPartMixed(aMsg, -1, aMsg.MessageParts.Count);
Exit;
end;
2: begin
DisplayHTML(aMsg.Body);
Exit;
end;
3: begin
DisplayPlainText(aMsg.Body);
Exit;
end;
else
// nothing supported to display...
end;
end;
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