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DataFlex

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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Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoPdf
    Variant vJson
    Handle hoJson
    Variant vCert
    Handle hoCert
    String sTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatPdf)) To hoPdf
    If (Not(IsComObjectCreated(hoPdf))) Begin
        Send CreateComObject of hoPdf
    End

    //  Load a PDF containing an unsigned signature field.
    Get ComLoadFile Of hoPdf "qa_data/pdf/unsigned_sig_field/due_diligence.pdf" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPdf To sTemp1
        Showln sTemp1
        Procedure_Return
    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.
    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End

    //  In most cases, the signingCertificateV2 and signingTime attributes are required.
    Get ComUpdateInt Of hoJson "signingCertificateV2" 1 To iSuccess
    Get ComUpdateInt Of hoJson "signingTime" 1 To iSuccess

    //  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.
    Get ComUpdateBool Of hoJson "appearance.fillUnsignedSignatureField" True To iSuccess

    //  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
    Get ComUpdateString Of hoJson "unsignedSignatureField" "doctor_signature" To iSuccess

    //  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.
    Get ComUpdateString Of hoJson "appearance.text[0]" "Digitally signed by: cert_cn" To iSuccess
    Get ComUpdateString Of hoJson "appearance.text[1]" "current_dt" To iSuccess
    Get ComUpdateString Of hoJson "appearance.text[2]" "The crazy brown fox jumps over the lazy dog." To iSuccess

    //  This signature will include one of the built-in SVG graphics (green-check-grey-circle).
    Get ComUpdateString Of hoJson "appearance.image" "green-check-grey-circle" To iSuccess
    Get ComUpdateString Of hoJson "appearance.imagePlacement" "left" To iSuccess

    //  Load the signing certificate. (Use your own certificate.)
    Get Create (RefClass(cComChilkatCert)) To hoCert
    If (Not(IsComObjectCreated(hoCert))) Begin
        Send CreateComObject of hoCert
    End
    Get ComLoadPfxFile Of hoCert "qa_data/pfx/myPdfSigningCert.pfx" "secret" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoCert To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Tell the pdf object to use the certificate for signing.
    Get pvComObject of hoCert to vCert
    Get ComSetSigningCert Of hoPdf vCert To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPdf To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get pvComObject of hoJson to vJson
    Get ComSignPdf Of hoPdf vJson "qa_output/due_diligence_signed.pdf" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPdf To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "The PDF has been successfully cryptographically signed."

    //  The appearance of the signature appears in Adobe Acrobat as shown below.
    //  image


End_Procedure