Harwinder Sekhon
44 lines
1.4 KiB
PHP
44 lines
1.4 KiB
PHP
<?php
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// Serves a cached course thumbnail — a frame captured from the course's first
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// video at THUMBNAIL_SEEK_PERCENT, generated by the scanner (see
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// generateThumbnails() in includes/functions.php). Looked up by folder ID
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// only, mirroring stream.php's containment check; 404s (no thumbnail yet, or
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// the id isn't a course) are expected and handled by the client falling back
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// to its colour-block placeholder.
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require_once __DIR__ . '/includes/auth.php';
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require_once __DIR__ . '/includes/functions.php';
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$userId = currentUserId();
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if ($userId === null) {
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http_response_code(403);
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exit('Forbidden');
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}
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$courseId = (int)($_GET['course_id'] ?? 0);
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$dir = realpath(THUMBNAILS_DIR);
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$file = ($courseId > 0 && $dir !== false)
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? realpath($dir . '/' . $courseId . '.jpg')
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: false;
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if ($dir === false || $file === false || !str_starts_with($file, $dir . DIRECTORY_SEPARATOR)
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|| !is_file($file)) {
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http_response_code(404);
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exit('No thumbnail');
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}
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$mtime = filemtime($file);
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$etag = '"' . md5($courseId . '-' . $mtime) . '"';
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header('Cache-Control: private, max-age=86400');
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header('ETag: ' . $etag);
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header('Last-Modified: ' . gmdate('D, d M Y H:i:s', $mtime) . ' GMT');
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if (($_SERVER['HTTP_IF_NONE_MATCH'] ?? null) === $etag) {
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http_response_code(304);
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exit;
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}
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header('Content-Type: image/jpeg');
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header('Content-Length: ' . filesize($file));
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readfile($file);
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