Xbase++

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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LOCAL nSuccess
LOCAL oEmail
LOCAL oBdImage
LOCAL cCid
LOCAL oSbHtml
LOCAL nNumReplaced
LOCAL cCid0

nSuccess := 0

//  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.

oEmail := CreateObject("Chilkat.Email")
oEmail:Subject := "GetRelatedContentID example"

//  Load the image data from a file into a BinData object.
oBdImage := CreateObject("Chilkat.BinData")
nSuccess := oBdImage:LoadFile("qa_data/images/logo.png")
IF (nSuccess == 0)
    ? oBdImage:LastErrorText
    oEmail:destroy()
    oBdImage:destroy()
    RETURN
ENDIF

//  Add the image as a related item from the BinData; capture its generated Content-ID.
cCid := oEmail:AddRelatedBd("logo.png", oBdImage)
IF (oEmail:LastMethodSuccess == 0)
    ? oEmail:LastErrorText
    oEmail:destroy()
    oBdImage:destroy()
    RETURN
ENDIF

//  Reference the related item in the HTML body by its Content-ID.
oSbHtml := CreateObject("Chilkat.StringBuilder")
oSbHtml:Append('<html><body><img src="cid:PLACEHOLDER_CID"/></body></html>')
nNumReplaced := oSbHtml:Replace("PLACEHOLDER_CID", cCid)
oEmail:SetHtmlBody(oSbHtml:GetAsString())

//  Read the Content-ID of the first related item (index 0).
cCid0 := oEmail:GetRelatedContentID(0)
? "Related item 0 Content-ID: " + cCid0

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

oEmail:destroy()
oBdImage:destroy()
oSbHtml:destroy()