Go Requires Chilkat v11.7.0+

Get a PDF Field Value by its Label (Value to the Right)

See more PDF Text Extraction Examples

Demonstrates the "label" option, which captures the text that belongs to a caption such as "Invoice Number:" without needing coordinates. With labelValue "right", the value is the rest of the label's line. Label matching ignores case, extra spaces and a trailing colon. Go

    success := false

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

    //  The invoice used in this example is available at invoice_labels.pdf

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

    json := chilkat.NewJsonObject()
    jsonOut := chilkat.NewJsonObject()

    //  The invoice has lines such as "Invoice Number:   INV-2026-0412".
    //  The label option restricts the "text" operation to the text belonging to the label.
    json.UpdateString("label","Invoice Number")

    //  "right" means the value is the rest of the label's line.
    //  (The default, "auto", uses the rest of the line if there is text there, otherwise the block below.)
    json.UpdateString("labelValue","right")

    success = pdf.ExtractText("text",json,jsonOut)
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    //  The value is returned as the text.
    fmt.Println("Invoice Number: ", *jsonOut.StringOf("text"))

    //  The labelMatches array tells where the label was found and how it appeared in the PDF.
    fmt.Println("Found on page ", jsonOut.IntOf("labelMatches[0].page"), " as \"", *jsonOut.StringOf("labelMatches[0].label"), "\"")

    //  Matching ignores case and the trailing colon, so these all work:
    json.UpdateString("label","CUSTOMER:")
    success = pdf.ExtractText("text",json,jsonOut)
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    fmt.Println("Customer: ", *jsonOut.StringOf("text"))

    json.UpdateString("label","due date")
    success = pdf.ExtractText("text",json,jsonOut)
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    fmt.Println("Due Date: ", *jsonOut.StringOf("text"))

    //  The totals at the foot of the invoice are right-aligned labels with the amount beside them.
    json.UpdateString("label","Total Due")
    success = pdf.ExtractText("text",json,jsonOut)
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    fmt.Println("Total Due: ", *jsonOut.StringOf("text"))

    //  A label that is not found is not an error.  The text is empty, labelMatches is empty,
    //  and the quality report has an issue with the code "labelNotFound".
    json.UpdateString("label","Tracking Number")
    success = pdf.ExtractText("text",json,jsonOut)
    if success == false {
        fmt.Println(pdf.LastErrorText())
        pdf.DisposePdf()
        json.DisposeJsonObject()
        jsonOut.DisposeJsonObject()
        return
    }

    if jsonOut.SizeOfArray("labelMatches") == 0 {
        fmt.Println("Tracking Number: (not found) ", *jsonOut.StringOf("quality.pages[0].issues[0].code"))
    }

    //  Sample output:

    //  Invoice Number: INV-2026-0412
    //  Found on page 1 as "Invoice Number:"
    //  Customer: Northwind Traders
    //  Due Date: April 13, 2026
    //  Total Due: $1,234.53
    //  Tracking Number: (not found) labelNotFound

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