(Ruby) 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.

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

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

pdf = Chilkat::CkPdf.new()

# Load a PDF to be signed.
success = pdf.LoadFile("qa_data/pdf/empty.pdf")
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

# Options for signing are specified in JSON.
json = Chilkat::CkJsonObject.new()

# In most cases, the signingCertificateV2 and signingTime attributes are required.
json.UpdateInt("signingCertificateV2",1)
json.UpdateInt("signingTime",1)

# Put the signature on page 1, top left
json.UpdateInt("page",1)
json.UpdateString("appearance.y","top")
json.UpdateString("appearance.x","left")

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

jpgData = Chilkat::CkBinData.new()
success = jpgData.LoadFile("qa_data/jpg/seal1.jpg")
if (success == false)
    print "Failed to load the JPG image." + "\n";
    exit
end

success = pdf.SetSignatureJpeg(jpgData)
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

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

# Load the signing certificate. (Use your own certificate.)
cert = Chilkat::CkCert.new()
success = cert.LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx","pfx_password")
if (success == false)
    print cert.lastErrorText() + "\n";
    exit
end

# Tell the pdf object to use the certificate for signing.
success = pdf.SetSigningCert(cert)
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

success = pdf.SignPdf(json,"qa_output/hello_signed.pdf")
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

print "The PDF has been successfully cryptographically signed." + "\n";

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