Rust

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.

Rust

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

let pdf = chilkat::Pdf::new();

// Load a PDF to be signed.
if pdf.load_file("qa_data/pdf/empty.pdf").is_err() {
    println!("{}", pdf.last_error_text());
    return;
}

// Options for signing are specified in JSON.
let json = chilkat::JsonObject::new();

// In most cases, the signingCertificateV2 and signingTime attributes are required.
let _ = json.update_int("signingCertificateV2", 1);
let _ = json.update_int("signingTime", 1);

// Put the signature on page 1, top left
let _ = json.update_int("page", 1);
let _ = json.update_string("appearance.y", "top");
let _ = json.update_string("appearance.x", "left");

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

let jpg_data = chilkat::BinData::new();
if jpg_data.load_file("qa_data/jpg/seal1.jpg").is_err() {
    println!("Failed to load the JPG image.");
    return;
}

if pdf.set_signature_jpeg(&jpg_data).is_err() {
    println!("{}", pdf.last_error_text());
    return;
}

// Specify that we want to display the JPG image in the center with 33% opacity.
let _ = json.update_string("appearance.image", "custom-jpg");
let _ = json.update_string("appearance.imagePlacement", "center");
let _ = json.update_string("appearance.imageOpacity", "33");

// Load the signing certificate. (Use your own certificate.)
let cert = chilkat::Cert::new();
if cert.load_pfx_file("qa_data/pfx/myPdfSigningCert.pfx", "pfx_password").is_err() {
    println!("{}", cert.last_error_text());
    return;
}

// Tell the pdf object to use the certificate for signing.
if pdf.set_signing_cert(&cert).is_err() {
    println!("{}", pdf.last_error_text());
    return;
}

if pdf.sign_pdf(&json, "qa_output/hello_signed.pdf").is_err() {
    println!("{}", pdf.last_error_text());
    return;
}

println!("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)