Go Requires Chilkat v11.7.0+

PDF Placeholders Without a Value: Error, Blank or Keep

See more PDF Text Replacement Examples

Demonstrates the "unusedPlaceholders" option, which decides what happens to a placeholder found on the page that has no value in "placeholders": "error" (the default) makes it a problem with the reason unusedPlaceholder, so nothing is applied; "blank" replaces it with nothing; "keep" leaves it on the page as it is. Go

    success := false

    //  This example requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    //  The PDF used in this example is available at invoice_template.pdf

    pdf := chilkat.NewPdf()
    success = pdf.LoadFile("qa_data/pdf/invoice_template.pdf")
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        return
    }

    //  Values for every placeholder except {{po}} (the purchase order number, which this customer has none of).
    json := chilkat.NewJsonObject()
    json.UpdateString("placeholders.customer","Acme Corp")
    json.UpdateString("placeholders.date","2026-10-18")
    json.UpdateString("placeholders.qty1","2")
    json.UpdateString("placeholders.desc1","Cordless drill, 18 V")
    json.UpdateString("placeholders.price1","$460.00")
    json.UpdateString("placeholders.amount1","$920.00")
    json.UpdateString("placeholders.qty2","6")
    json.UpdateString("placeholders.desc2","Galvanized hinge, 4 inch")
    json.UpdateString("placeholders.price2","$12.50")
    json.UpdateString("placeholders.amount2","$75.00")
    json.UpdateString("placeholders.subtotal","$995.00")
    json.UpdateString("placeholders.taxRate","7.35%")
    json.UpdateString("placeholders.tax","$73.13")
    json.UpdateString("placeholders.total","$1,068.13")

    jsonOut := chilkat.NewJsonObject()

    //  The default, "error": the unfilled {{po}} is a problem and nothing would be applied.
    success = pdf.TextReplace("check",json,jsonOut)
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    fmt.Println("error (default): ok = ", *jsonOut.BoolOf("ok"), ", problem: ", *jsonOut.StringOf("problems[0].field"), " ", *jsonOut.StringOf("problems[0].reason"))

    //  "keep": {{po}} stays on the page, literally.
    json.UpdateString("unusedPlaceholders","keep")
    success = pdf.TextReplace("check",json,jsonOut)
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    fmt.Println("keep: ok = ", *jsonOut.BoolOf("ok"))

    //  "blank": {{po}} is replaced by nothing, leaving "PO Number:" with an empty value.
    json.UpdateString("unusedPlaceholders","blank")
    success = pdf.TextReplace("apply",json,jsonOut)
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    fmt.Println("blank: applied = ", *jsonOut.BoolOf("applied"))

    success = pdf.WriteFile("qa_output/invoice_no_po.pdf")
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    //  Sample output:

    //  error (default): ok = false, problem: po unusedPlaceholder
    //  keep: ok = true
    //  blank: applied = true

    pdf.DisposePdf()
    json.DisposeJsonObject()
    jsonOut.DisposeJsonObject()