PureBasic

PDF Signature Appearance Text Substitution Keywords

See more PDF Signatures Examples

This example demonstrates the text substitution keywords that can be used in the PDF signature's appearance text.

Note: This example requires Chilkat v9.5.0.85 or greater.

PureBasic

IncludeFile "CkBinData.pb"
IncludeFile "CkCert.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkPdf.pb"

Procedure ChilkatExample()

    success.i = 0

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

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

    ; Load a PDF to be signed.
    success = CkPdf::ckLoadFile(pdf,"qa_data/pdf/empty.pdf")
    If success = 0
        Debug CkPdf::ckLastErrorText(pdf)
        CkPdf::ckDispose(pdf)
        ProcedureReturn
    EndIf

    ; Options for signing are specified in JSON.
    json.i = CkJsonObject::ckCreate()
    If json.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; In most cases, the signingCertificateV2 and signingTime attributes are required.
    CkJsonObject::ckUpdateInt(json,"signingCertificateV2",1)
    CkJsonObject::ckUpdateInt(json,"signingTime",1)

    ; Put the signature on page 1, top left
    CkJsonObject::ckUpdateInt(json,"page",1)
    CkJsonObject::ckUpdateString(json,"appearance.y","top")
    CkJsonObject::ckUpdateString(json,"appearance.x","left")

    ; Use a font scale of 7.0
    CkJsonObject::ckUpdateString(json,"appearance.fontScale","7.0")

    ; The appearance of the PDF signature can contain any number of text lines.
    ; Chilkat has defined a number of special keywords that can be used in any text line.
    ; Each keyword is replaced with the actual value.
    ; For example, "cert_cn" is replaced with the certificate subject's common name (CN).

    ; Here we are creating a signature with many lines of text, to demonstrate each
    ; keyword.
    CkJsonObject::ckUpdateString(json,"appearance.text[0]","Date/time in PDF format: current_dt")
    CkJsonObject::ckUpdateString(json,"appearance.text[1]","Current Local date/time: current_datetime")
    CkJsonObject::ckUpdateString(json,"appearance.text[2]","GMT Timestamp: current_timestamp_gmt")
    CkJsonObject::ckUpdateString(json,"appearance.text[3]","Local Timestamp: current_timestamp_local")
    CkJsonObject::ckUpdateString(json,"appearance.text[4]","GMT RFC822 date/time: current_rfc822_dt_gmt")
    CkJsonObject::ckUpdateString(json,"appearance.text[5]","Local RFC822 date/time: current_rfc822_dt_local")
    CkJsonObject::ckUpdateString(json,"appearance.text[6]","Cert DN (Distinguished Name): cert_dn")
    CkJsonObject::ckUpdateString(json,"appearance.text[7]","Cert Common Name: cert_cn")
    CkJsonObject::ckUpdateString(json,"appearance.text[8]","Cert Organizational ID (2.5.4.97): cert_org_id")
    CkJsonObject::ckUpdateString(json,"appearance.text[9]","Cert Email: cert_email")
    CkJsonObject::ckUpdateString(json,"appearance.text[10]","Cert Organization: cert_organization")
    CkJsonObject::ckUpdateString(json,"appearance.text[11]","Cert Organziational Unit: cert_ou")
    CkJsonObject::ckUpdateString(json,"appearance.text[12]","Cert State: cert_state")
    CkJsonObject::ckUpdateString(json,"appearance.text[13]","Cert Country: cert_country")
    CkJsonObject::ckUpdateString(json,"appearance.text[14]","Cert Locality: cert_locality")
    CkJsonObject::ckUpdateString(json,"appearance.text[15]","Cert Serial Number (hex): cert_serial_hex")
    CkJsonObject::ckUpdateString(json,"appearance.text[16]","Cert Serial Number (decimal): cert_serial_dec")
    CkJsonObject::ckUpdateString(json,"appearance.text[17]","Cert Thumbprint: cert_thumbprint")
    CkJsonObject::ckUpdateString(json,"appearance.text[18]","Cert Issuer Common Name: cert_issuer_cn")

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

    success = CkBinData::ckLoadFile(jpgData,"qa_data/jpg/seal1.jpg")
    If success = 0
        Debug "Failed to load the JPG image."
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkBinData::ckDispose(jpgData)
        ProcedureReturn
    EndIf

    success = CkPdf::ckSetSignatureJpeg(pdf,jpgData)
    If success = 0
        Debug CkPdf::ckLastErrorText(pdf)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkBinData::ckDispose(jpgData)
        ProcedureReturn
    EndIf

    ; Specify that we want to display the JPG image in the center with 33% opacity.
    CkJsonObject::ckUpdateString(json,"appearance.image","custom-jpg")
    CkJsonObject::ckUpdateString(json,"appearance.imagePlacement","center")
    CkJsonObject::ckUpdateString(json,"appearance.imageOpacity","33")

    ; Load the signing certificate. (Use your own certificate.)
    cert.i = CkCert::ckCreate()
    If cert.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkCert::ckLoadPfxFile(cert,"qa_data/pfx/myPdfSigningCert.pfx","pfx_password")
    If success = 0
        Debug CkCert::ckLastErrorText(cert)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkBinData::ckDispose(jpgData)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    ; Tell the pdf object to use the certificate for signing.
    success = CkPdf::ckSetSigningCert(pdf,cert)
    If success = 0
        Debug CkPdf::ckLastErrorText(pdf)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkBinData::ckDispose(jpgData)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    success = CkPdf::ckSignPdf(pdf,json,"qa_output/hello_signed.pdf")
    If success = 0
        Debug CkPdf::ckLastErrorText(pdf)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkBinData::ckDispose(jpgData)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    Debug "The PDF has been successfully cryptographically signed."

    ; The appearance of the signature appears in Adobe Acrobat as shown here:

    ; (image:https://example-code.com/images/pdf_signature_text_replacements.jpg/endImage)


    CkPdf::ckDispose(pdf)
    CkJsonObject::ckDispose(json)
    CkBinData::ckDispose(jpgData)
    CkCert::ckDispose(cert)


    ProcedureReturn
EndProcedure