PHP Requires Chilkat v11.7.0+

PDF Placeholders Without a Value: Error, Blank or Keep

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Demonstrates the "unusedPlaceholders" option, which decides what happens to a placeholder found on the page that has no value in "placeholders": "error" (the default) makes it a problem with the reason unusedPlaceholder, so nothing is applied; "blank" replaces it with nothing; "keep" leaves it on the page as it is. Chilkat2 PHP

<?php

use Chilkat2\JsonObject;
use Chilkat2\Pdf;

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

// The PDF used in this example is available at invoice_template.pdf

$pdf = new Pdf();
try {
    $pdf->LoadFile('qa_data/pdf/invoice_template.pdf');

    // Values for every placeholder except {{po}} (the purchase order number, which this customer has none of).
    $json = new JsonObject();
    $json->UpdateString('placeholders.customer', 'Acme Corp');
    $json->UpdateString('placeholders.date', '2026-10-18');
    $json->UpdateString('placeholders.qty1', '2');
    $json->UpdateString('placeholders.desc1', 'Cordless drill, 18 V');
    $json->UpdateString('placeholders.price1', '$460.00');
    $json->UpdateString('placeholders.amount1', '$920.00');
    $json->UpdateString('placeholders.qty2', '6');
    $json->UpdateString('placeholders.desc2', 'Galvanized hinge, 4 inch');
    $json->UpdateString('placeholders.price2', '$12.50');
    $json->UpdateString('placeholders.amount2', '$75.00');
    $json->UpdateString('placeholders.subtotal', '$995.00');
    $json->UpdateString('placeholders.taxRate', '7.35%');
    $json->UpdateString('placeholders.tax', '$73.13');
    $json->UpdateString('placeholders.total', '$1,068.13');

    $jsonOut = new JsonObject();

    // The default, "error": the unfilled {{po}} is a problem and nothing would be applied.
    $pdf->TextReplace('check', $json, $jsonOut);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo 'error (default): ok = ', ($jsonOut->BoolOf('ok') ? 'true' : 'false'), ', problem: ', $jsonOut->StringOf('problems[0].field'), ' ', $jsonOut->StringOf('problems[0].reason'), "\n";

// "keep": {{po}} stays on the page, literally.
$json->UpdateString('unusedPlaceholders', 'keep');
try {
    $pdf->TextReplace('check', $json, $jsonOut);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo 'keep: ok = ', ($jsonOut->BoolOf('ok') ? 'true' : 'false'), "\n";

// "blank": {{po}} is replaced by nothing, leaving "PO Number:" with an empty value.
$json->UpdateString('unusedPlaceholders', 'blank');
try {
    $pdf->TextReplace('apply', $json, $jsonOut);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo 'blank: applied = ', ($jsonOut->BoolOf('applied') ? 'true' : 'false'), "\n";

try {
    $pdf->WriteFile('qa_output/invoice_no_po.pdf');
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Sample output:

// error (default): ok = false, problem: po unusedPlaceholder
// keep: ok = true
// blank: applied = true