Delphi DLL

Get a Header Attribute of a Related Item

Demonstrates the Chilkat Email.GetRelatedAttr method, which returns a header-field attribute value from a header field of the Nth related item. The first argument is the zero-based related-item index, the second names a header field, and the third names an attribute within it. This example loads an image from a file into a BinData object, adds it as a related item with AddRelatedBd (capturing the generated Content-ID and referencing it from the HTML), then reads the name attribute of the related item's Content-Type header.

Background: Related items (inline images, style sheets) are MIME parts whose headers may carry named parameters — for instance Content-Type: image/png; name="logo.png". Because an image is binary, it is loaded into a BinData object (here from a file) and added with AddRelatedBd, rather than being treated as text. GetRelatedAttr then extracts one named attribute from a chosen header of a specific related part, the related-item analogue of GetAttachmentAttr, so you don't have to parse the raw header yourself.

Chilkat Delphi DLL Downloads

Download Chilkat for Delphi DLL

Delphi DLL

var
success: Boolean;
email: HCkEmail;
bdImage: HCkBinData;
cid: PWideChar;
sbHtml: HCkStringBuilder;
numReplaced: Integer;
val: PWideChar;

begin
success := False;

//  Demonstrates the GetRelatedAttr method, which returns a header-field attribute value
//  from a header field of the Nth related item.  The first argument is the zero-based related-item
//  index, the second is the header field name, and the third is the attribute name.

email := CkEmail_Create();
CkEmail_putSubject(email,'GetRelatedAttr example');

//  Load the image data from a file into a BinData object.
bdImage := CkBinData_Create();
success := CkBinData_LoadFile(bdImage,'qa_data/images/logo.png');
if (success = False) then
  begin
    Memo1.Lines.Add(CkBinData__lastErrorText(bdImage));
    Exit;
  end;

//  Add the image as a related item from the BinData; capture its generated Content-ID.
cid := CkEmail__addRelatedBd(email,'logo.png',bdImage);
if (CkEmail_getLastMethodSuccess(email) = False) then
  begin
    Memo1.Lines.Add(CkEmail__lastErrorText(email));
    Exit;
  end;

//  Reference the related item in the HTML body by its Content-ID.
sbHtml := CkStringBuilder_Create();
CkStringBuilder_Append(sbHtml,'<html><body><img src="cid:PLACEHOLDER_CID"/></body></html>');
numReplaced := CkStringBuilder_Replace(sbHtml,'PLACEHOLDER_CID',cid);
CkEmail_SetHtmlBody(email,CkStringBuilder__getAsString(sbHtml));

//  Get the "name" attribute of the related item's Content-Type header (index 0).
val := CkEmail__getRelatedAttr(email,0,'Content-Type','name');
Memo1.Lines.Add('Related item Content-Type name attribute: ' + val);

//  Note: The path "qa_data/images/logo.png" is a relative local filesystem path,
//  relative to the current working directory of the running application.

CkEmail_Dispose(email);
CkBinData_Dispose(bdImage);
CkStringBuilder_Dispose(sbHtml);