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Editing: qr-proxy.php

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<?php
/**********************************************************************
 * qr-proxy.php – one‑file QR cacher
 * -------------------------------------------------------------------
 *  Accepts ?data=<URL‑encoded vCard>
 *  Saves   /social/<slug>/qr.png   or   /ph/<digits>/qr.png
 **********************************************************************/

/* 1. Basic sanity check ------------------------------------------------ */
if (empty($_GET['data'])) {
    http_response_code(400);
    exit('Missing ?data');
}
$vcard = urldecode($_GET['data']);   // make it readable

/* 2. Derive absolute folder from decoded vCard ------------------------ */
$root = $_SERVER['DOCUMENT_ROOT'];   // e.g. /var/www/html
$profileDir = null;

if (preg_match('#https?://[^/]+/(social|ph)/([A-Za-z0-9_]+)/?#i', $vcard, $m)) {
    $profileDir = "$root/{$m[1]}/{$m[2]}";   // e.g. /var/www/html/social/jane
}
if (!$profileDir) {
    http_response_code(400);
    exit('Could not find /social/… or /ph/… path in vCard');
}
@mkdir($profileDir, 0775, true);      // ensure folder exists (ignore if already)

/* 3. Local + remote PNG paths ----------------------------------------- */
$localPng  = $profileDir . '/qr.png';
$remoteUrl = 'https://api.qrserver.com/v1/create-qr-code/'
           . '?size=170x170&data=' . urlencode($_GET['data']);

/* 4. Try to fetch a fresh PNG ----------------------------------------- */
$pngData = @file_get_contents($remoteUrl);          // silent network errors
$good    = $pngData && strncmp($pngData, "\x89PNG", 4) === 0;

if ($good) {                                         // save new copy
    @file_put_contents($localPng, $pngData, LOCK_EX);
} elseif (is_readable($localPng)) {                  // fallback to cache
    $pngData = file_get_contents($localPng);
} else {                                             // nothing to serve
    http_response_code(502);
    exit('QR service down & no cached image');
}

/* 5. Send PNG to browser ---------------------------------------------- */
header('Content-Type: image/png');
header('Cache-Control: public, max-age=604800');     // 7 days client cache
echo $pngData;

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Editing: qr-proxy.php

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