Delphi DLL

Get the Content-ID of a Related Item

Demonstrates the Chilkat Email.GetRelatedContentID method, which returns the Content-ID of a related item (typically an image or style sheet embedded within an HTML email). The index is zero-based. 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 that Content-ID back.

Background: The Content-ID is the anchor that ties an inline resource to the HTML that displays it: the body references cid: plus the ID, and the matching related part carries that same Content-ID. Because an image is binary, it is loaded into a BinData object (here from a file) and added with AddRelatedBd. Reading the Content-ID back lets a program verify or rewrite those links — for example when relocating embedded images or converting a message for display outside a mail client.

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var
success: Boolean;
email: HCkEmail;
bdImage: HCkBinData;
cid: PWideChar;
sbHtml: HCkStringBuilder;
numReplaced: Integer;
cid0: PWideChar;

begin
success := False;

//  Demonstrates the GetRelatedContentID method, which returns the Content-ID of a related
//  item.  Related items are typically images and style sheets embedded within HTML emails.
//  The index is zero-based.

email := CkEmail_Create();
CkEmail_putSubject(email,'GetRelatedContentID 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));

//  Read the Content-ID of the first related item (index 0).
cid0 := CkEmail__getRelatedContentID(email,0);
Memo1.Lines.Add('Related item 0 Content-ID: ' + cid0);

//  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);