102 lines
2.5 KiB
PHP
102 lines
2.5 KiB
PHP
<?php
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declare(strict_types=1);
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header("Content-Type: text/html; charset=UTF-8");
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header("X-Content-Type-Options: nosniff");
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header("Referrer-Policy: strict-origin-when-cross-origin");
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header("Permissions-Policy: geolocation=(), microphone=(), camera=()");
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header(
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"Content-Security-Policy: default-src 'none'; base-uri 'none'; form-action 'none'; frame-ancestors *",
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);
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if (function_exists("header_remove")) {
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header_remove("X-Frame-Options");
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}
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function normalizeHost(string $value): ?string
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{
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$value = trim(strtolower($value));
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if ($value === "") {
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return null;
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}
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if (preg_match("#^https?://#", $value) === 1) {
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$parsedHost = parse_url($value, PHP_URL_HOST);
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if (!is_string($parsedHost) || $parsedHost === "") {
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return null;
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}
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$value = strtolower($parsedHost);
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}
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$value = explode("/", $value, 2)[0];
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if (
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preg_match(
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"/\A(?=.{1,253}\z)(?:[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?\.)+[a-z]{2,63}\z/",
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$value,
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) !== 1
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) {
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return null;
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}
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return $value;
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}
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$rawSites = file(
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__DIR__ . "/sites.txt",
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FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES,
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);
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if ($rawSites === false) {
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http_response_code(500);
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echo ";_;";
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exit();
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}
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$sites = [];
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foreach ($rawSites as $rawSite) {
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$normalized = normalizeHost($rawSite);
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if ($normalized !== null) {
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$sites[] = $normalized;
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}
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}
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$sites = array_values(array_unique($sites));
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if (count($sites) < 2) {
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http_response_code(500);
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echo "did't find at least two sites to ring among";
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exit();
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}
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$current = normalizeHost((string) ($_GET["site"] ?? ""));
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if ($current === null) {
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http_response_code(400);
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echo "genuinely what are we doing here";
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exit();
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}
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$index = array_search($current, $sites, true);
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if ($index === false) {
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http_response_code(404);
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echo "This site isn't actually part of the ringularity ;-;";
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exit();
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}
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$total = count($sites);
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$prev = $sites[($index - 1 + $total) % $total];
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$next = $sites[($index + 1) % $total];
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?>
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<div class="webring" role="navigation" aria-label="Webring navigation">
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<a href="https://<?= htmlspecialchars(
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$prev,
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ENT_QUOTES | ENT_SUBSTITUTE,
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"UTF-8",
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) ?>" target="_top" rel="noopener noreferrer">← PREV</a>
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<span aria-hidden="true"> | </span>
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<a href="https://<?= htmlspecialchars(
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$next,
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ENT_QUOTES | ENT_SUBSTITUTE,
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"UTF-8",
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) ?>" target="_top" rel="noopener noreferrer">NEXT →</a>
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</div>
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