PowerBuilder

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.

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integer li_rc
integer li_Success
oleobject loo_Email
oleobject loo_BdImage
string ls_Cid
oleobject loo_SbHtml
integer li_NumReplaced
string ls_Val

li_Success = 0

//  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.

loo_Email = create oleobject
li_rc = loo_Email.ConnectToNewObject("Chilkat.Email")
if li_rc < 0 then
    destroy loo_Email
    MessageBox("Error","Connecting to COM object failed")
    return
end if
loo_Email.Subject = "GetRelatedAttr example"

//  Load the image data from a file into a BinData object.
loo_BdImage = create oleobject
li_rc = loo_BdImage.ConnectToNewObject("Chilkat.BinData")

li_Success = loo_BdImage.LoadFile("qa_data/images/logo.png")
if li_Success = 0 then
    Write-Debug loo_BdImage.LastErrorText
    destroy loo_Email
    destroy loo_BdImage
    return
end if

//  Add the image as a related item from the BinData; capture its generated Content-ID.
ls_Cid = loo_Email.AddRelatedBd("logo.png",loo_BdImage)
if loo_Email.LastMethodSuccess = 0 then
    Write-Debug loo_Email.LastErrorText
    destroy loo_Email
    destroy loo_BdImage
    return
end if

//  Reference the related item in the HTML body by its Content-ID.
loo_SbHtml = create oleobject
li_rc = loo_SbHtml.ConnectToNewObject("Chilkat.StringBuilder")

loo_SbHtml.Append("<html><body><img src=~"cid:PLACEHOLDER_CID~"/></body></html>")
li_NumReplaced = loo_SbHtml.Replace("PLACEHOLDER_CID",ls_Cid)
loo_Email.SetHtmlBody(loo_SbHtml.GetAsString())

//  Get the "name" attribute of the related item's Content-Type header (index 0).
ls_Val = loo_Email.GetRelatedAttr(0,"Content-Type","name")
Write-Debug "Related item Content-Type name attribute: " + ls_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.


destroy loo_Email
destroy loo_BdImage
destroy loo_SbHtml