PureBasic

Add a Related File to an HTML Email

Demonstrates the Chilkat Email.AddRelatedFile method, which adds the contents of a local file as a related MIME resource and returns the generated Content-ID. The returned value is the bare Content-ID — no angle brackets and no cid: prefix — so if it returns CID-123@example, the HTML reference is cid:CID-123@example. Because the Content-ID is generated by the call, this example adds the image first, then builds the HTML body in a StringBuilder — using a placeholder in the <img> tag that is replaced with the returned Content-ID — and passes the result to SetHtmlBody.

Background: To embed an image so it displays inside an HTML email (rather than being downloaded from a web server), you add it as a "related" part and reference it from the HTML with a cid: URL that matches the part's Content-ID. Since Chilkat assigns that ID when you add the file, the natural order is: add the related file, capture the returned ID, then build the <img src="cid:..."> reference from it. A StringBuilder makes assembling and updating the HTML convenient.

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PureBasic

IncludeFile "CkStringBuilder.pb"
IncludeFile "CkEmail.pb"

Procedure ChilkatExample()

    ;  Demonstrates the AddRelatedFile method, which adds a local file as a related MIME
    ;  resource (such as an image displayed by an HTML body) and returns the generated
    ;  Content-ID.  The HTML references the item using cid:<Content-ID>.

    email.i = CkEmail::ckCreate()
    If email.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkEmail::setCkSubject(email, "Email with a related image")

    ;  Add the image file as a related item first.  The return value is the bare Content-ID
    ;  (no angle brackets and no "cid:" prefix).
    cid.s = CkEmail::ckAddRelatedFile(email,"qa_data/images/logo.png")
    If CkEmail::ckLastMethodSuccess(email) = 0
        Debug CkEmail::ckLastErrorText(email)
        CkEmail::ckDispose(email)
        ProcedureReturn
    EndIf

    ;  Build the HTML body in a StringBuilder, using a placeholder where the image's
    ;  Content-ID will go.
    sbHtml.i = CkStringBuilder::ckCreate()
    If sbHtml.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkStringBuilder::ckAppend(sbHtml,"<html><body><img src=" + Chr(34) + "cid:PLACEHOLDER_CID" + Chr(34) + "/></body></html>")

    ;  Replace the placeholder with the actual Content-ID returned by AddRelatedFile.
    numReplaced.i = CkStringBuilder::ckReplace(sbHtml,"PLACEHOLDER_CID",cid)

    ;  Set the HTML body from the StringBuilder result.
    CkEmail::ckSetHtmlBody(email,CkStringBuilder::ckGetAsString(sbHtml))

    Debug "Related Content-ID = " + cid
    Debug "NumRelatedItems = " + Str(CkEmail::ckNumRelatedItems(email))

    ;  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::ckDispose(email)
    CkStringBuilder::ckDispose(sbHtml)


    ProcedureReturn
EndProcedure