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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.

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LOCAL nSuccess
LOCAL oPdf
LOCAL oJson
LOCAL oJpgData
LOCAL oCert

nSuccess := 0

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

oPdf := CreateObject("Chilkat.Pdf")

//  Load a PDF to be signed.
nSuccess := oPdf:LoadFile("qa_data/pdf/empty.pdf")
IF (nSuccess == 0)
    ? oPdf:LastErrorText
    oPdf:destroy()
    RETURN
ENDIF

//  Options for signing are specified in JSON.
oJson := CreateObject("Chilkat.JsonObject")

//  In most cases, the signingCertificateV2 and signingTime attributes are required.
oJson:UpdateInt("signingCertificateV2", 1)
oJson:UpdateInt("signingTime", 1)

//  Put the signature on page 1, top left
oJson:UpdateInt("page", 1)
oJson:UpdateString("appearance.y", "top")
oJson:UpdateString("appearance.x", "left")

//  Use a font scale of 7.0
oJson:UpdateString("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.
oJson:UpdateString("appearance.text[0]", "Date/time in PDF format: current_dt")
oJson:UpdateString("appearance.text[1]", "Current Local date/time: current_datetime")
oJson:UpdateString("appearance.text[2]", "GMT Timestamp: current_timestamp_gmt")
oJson:UpdateString("appearance.text[3]", "Local Timestamp: current_timestamp_local")
oJson:UpdateString("appearance.text[4]", "GMT RFC822 date/time: current_rfc822_dt_gmt")
oJson:UpdateString("appearance.text[5]", "Local RFC822 date/time: current_rfc822_dt_local")
oJson:UpdateString("appearance.text[6]", "Cert DN (Distinguished Name): cert_dn")
oJson:UpdateString("appearance.text[7]", "Cert Common Name: cert_cn")
oJson:UpdateString("appearance.text[8]", "Cert Organizational ID (2.5.4.97): cert_org_id")
oJson:UpdateString("appearance.text[9]", "Cert Email: cert_email")
oJson:UpdateString("appearance.text[10]", "Cert Organization: cert_organization")
oJson:UpdateString("appearance.text[11]", "Cert Organziational Unit: cert_ou")
oJson:UpdateString("appearance.text[12]", "Cert State: cert_state")
oJson:UpdateString("appearance.text[13]", "Cert Country: cert_country")
oJson:UpdateString("appearance.text[14]", "Cert Locality: cert_locality")
oJson:UpdateString("appearance.text[15]", "Cert Serial Number (hex): cert_serial_hex")
oJson:UpdateString("appearance.text[16]", "Cert Serial Number (decimal): cert_serial_dec")
oJson:UpdateString("appearance.text[17]", "Cert Thumbprint: cert_thumbprint")
oJson:UpdateString("appearance.text[18]", "Cert Issuer Common Name: cert_issuer_cn")

oJpgData := CreateObject("Chilkat.BinData")
nSuccess := oJpgData:LoadFile("qa_data/jpg/seal1.jpg")
IF (nSuccess == 0)
    ? "Failed to load the JPG image."
    oPdf:destroy()
    oJson:destroy()
    oJpgData:destroy()
    RETURN
ENDIF

nSuccess := oPdf:SetSignatureJpeg(oJpgData)
IF (nSuccess == 0)
    ? oPdf:LastErrorText
    oPdf:destroy()
    oJson:destroy()
    oJpgData:destroy()
    RETURN
ENDIF

//  Specify that we want to display the JPG image in the center with 33% opacity.
oJson:UpdateString("appearance.image", "custom-jpg")
oJson:UpdateString("appearance.imagePlacement", "center")
oJson:UpdateString("appearance.imageOpacity", "33")

//  Load the signing certificate. (Use your own certificate.)
oCert := CreateObject("Chilkat.Cert")
nSuccess := oCert:LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx", "pfx_password")
IF (nSuccess == 0)
    ? oCert:LastErrorText
    oPdf:destroy()
    oJson:destroy()
    oJpgData:destroy()
    oCert:destroy()
    RETURN
ENDIF

//  Tell the pdf object to use the certificate for signing.
nSuccess := oPdf:SetSigningCert(oCert)
IF (nSuccess == 0)
    ? oPdf:LastErrorText
    oPdf:destroy()
    oJson:destroy()
    oJpgData:destroy()
    oCert:destroy()
    RETURN
ENDIF

nSuccess := oPdf:SignPdf(oJson, "qa_output/hello_signed.pdf")
IF (nSuccess == 0)
    ? oPdf:LastErrorText
    oPdf:destroy()
    oJson:destroy()
    oJpgData:destroy()
    oCert:destroy()
    RETURN
ENDIF

? "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)

oPdf:destroy()
oJson:destroy()
oJpgData:destroy()
oCert:destroy()