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Ruby

PDF Sign Unsigned Signature Field

See more PDF Signatures Examples

Demonstrates how to sign a PDF's unsigned signature field.

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

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Ruby 
require 'chilkat'

success = false

#  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 containing an unsigned signature field.
success = pdf.LoadFile("qa_data/pdf/unsigned_sig_field/due_diligence.pdf")
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

#  A PDF with an unsigned signature field appears in Adobe Acrobat as shown below.
#  (When the mouse pointer is hovered over the field, a tooltip will likely show a message
#  such as "Unsigned signature field (Click to sign)".  
#  This example code will automatically find the unsigned signature field,
#  and signs using your certificate.  It automatically sizes the text to the space alotted
#  for the signature.
#  image

#  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)

#  We don't specify the page or a specific location because Chilkat will automatically
#  find the unsigned signature field and use its location and size and will scale the
#  signatures visual appearance (text + graphics) to the correct size required to fit.
#  We only need to indicate the desire to fill the unsigned signature field.
json.UpdateBool("appearance.fillUnsignedSignatureField",true)

#  Starting in Chilkat v9.5.0.90, if a PDF contains multiple unsigned signature fields,
#  the field to be signed can be chosen by name:
#  To list unsigned signature fields, see this example: List PDF Unsigned Signature Fields
json.UpdateString("unsignedSignatureField","doctor_signature")

#  Note: If the PDF document contains multiple unsigned signature fields, Chilkat will 
#  sign the 1st one found. 

#  In this example, the appearance of the digital signature will contain three lines:
#  1) The signing certificate's common name
#  2) The current date/time
#  3) Some arbitrary text.
#  The keyword "cert_cn" is replaced with the Certificate's Subject Common Name.
#  The keyword "current_dt" is replaced with the current date/time.
#  Any number of appearance text lines can be added.
json.UpdateString("appearance.text[0]","Digitally signed by: cert_cn")
json.UpdateString("appearance.text[1]","current_dt")
json.UpdateString("appearance.text[2]","The crazy brown fox jumps over the lazy dog.")

#  This signature will include one of the built-in SVG graphics (green-check-grey-circle).
json.UpdateString("appearance.image","green-check-grey-circle")
json.UpdateString("appearance.imagePlacement","left")

#  Load the signing certificate. (Use your own certificate.)
cert = Chilkat::CkCert.new()
success = cert.LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx","secret")
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/due_diligence_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 below.
#  image