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Version: v6

PDF Invoice Hooks – gfpdf_invoice_number

Description​

Use this filter to override the invoice number (including prefix and suffix) displayed in PDF Invoices.

info

This hook allows you to modify the invoice number on-demand, and would not normally be used to generate a unique ID (use a hook like gform_entry_created).

Arguments​

The following arguments are passed to functions that use this hook:

$formatted_invoice_number | string​

  • The concatenated prefix, invoice number, and suffix

$invoice_prefix | string​

  • The value of the Invoice Prefix PDF setting

$invoice_suffix | string​

  • The value of the Invoice Suffix PDF setting

$invoice_number | string​

  • The value of the Invoice Number PDF setting

$settings | array​

  • The PDF Invoice settings

$entry | array​

  • The current Gravity Forms Entry

$form | array​

  • The current Gravity Forms form

Usage​

Change the Invoice Suffix entry submission year across all PDF invoices on all forms:

add_filter( 'gfpdf_invoice_number', function( $formatted_invoice_number, $invoice_prefix, $invoice_suffix, $invoice_number, $settings, $entry, $form ) {
    return $invoice_prefix . $invoice_number . '-' . wp_date( 'Y', strtotime( $entry['date_created'] ) );
}, 10, 7 );

Change the Invoice Suffix entry submission year across all PDF invoices for a specific form:

add_filter( 'gfpdf_invoice_number', function( $formatted_invoice_number, $invoice_prefix, $invoice_suffix, $invoice_number, $settings, $entry, $form ) {
    if ( (int) $form['id'] === 20 ) {
        return $invoice_prefix . $invoice_number . '-' . wp_date( 'Y', strtotime( $entry['date_created'] ) );
    }
    
    return $formatted_invoice_number;
}, 10, 7 );

Source Code​

This hook can be found in the Gpdf_Invoice_Base::get_invoice_number() method, which is located in the /config/gpdf-invoice-base.php file in the PDF Working Directory.