dsewerek.github.io/404.html at main · dsewerek/dsewerek.github.io · GitHub

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<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <title>Redirecting...</title>
    <style>
      /* Only used in "display" mode, when the issue content isn't a link */
      body {
        font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
        max-width: 700px;
        margin: 3rem auto;
        padding: 0 1rem;
        color: #1a1a1a;
        line-height: 1.5;
        white-space: pre-wrap;
        display: none; /* revealed only if we end up rendering content */
      }
    </style>
    <script>
      /**
       * ============================
       *  CONFIGURATION
       * ============================
       */
      var CONFIG = {
        // owner/repo whose issues back this redirector
        repo: "dsewerek/dsewerek",

        // how many path segments to skip before the "slug" part of the URL
        // e.g. for https://dsewerek.github.io/<skip>/WHATEVER_I_WANT -> 1
        // any remaining segments are rejoined with "/" as the slug, so
        // /go/foo/bar also works as a key of "foo/bar"
        pathSegmentsToSkip: 0,

        // field on the issue used as the lookup KEY (the slug you type in the URL)
        keyField: "title",

        // field on the issue used as the VALUE (the redirect target / content)
        valueField: "body",

        // match slug against keyField case-insensitively
        caseSensitive: false,

        // "redirect": only ever try to redirect; if invalid, fall back to homepage
        // "display" : never redirect; always show the raw content on the page
        // "auto"    : redirect if the content looks like a valid link target,
        //             otherwise just display the content as-is
        mode: "redirect",

        // URL schemes that are considered valid redirect targets when found
        // as an absolute URL (only relevant in "redirect"/"auto" modes)
        allowedSchemes: ["http:", "https:", "mailto:", "tel:", "ftp:"],

        // allow relative / path-only targets, e.g. "/docs/setup" or "../foo.html"
        allowRelativePaths: true,

        // block redirecting back to the exact same host (avoids obvious loops)
        preventSameHostRedirect: true,

        // issues are listed via the API (state=all, up to 100 per page); bump
        // this if you have more than a few hundred entries and need more pages
        maxPagesToScan: 3,
      };

      /**
       * ============================
       *  DO NOT TOUCH BELOW THIS LINE
       *  UNLESS YOU KNOW WHAT YOU ARE DOING
       * ============================
       */
      var GITHUB_ISSUES_LIST =
        "https://api.github.com/repos/" +
        CONFIG.repo +
        "/issues?state=all&per_page=100";

      function parseUrl(candidate) {
        var a = document.createElement("a");
        a.setAttribute("href", candidate);
        return a;
      }

      // Absolute URL with an allowed scheme, e.g. https://example.com/foo
      function isAbsoluteAllowedUrl(str) {
        var re = /^([a-zA-Z][a-zA-Z0-9+.-]*):/; // scheme:...
        var match = re.exec(str);
        if (!match) return false;
        var scheme = match[1].toLowerCase() + ":";
        return CONFIG.allowedSchemes.indexOf(scheme) !== -1;
      }

      // Bare relative/path-only target: "/foo", "foo/bar", "../baz", "?q=1", "#frag"
      function isRelativePath(str) {
        if (!CONFIG.allowRelativePaths) return false;
        if (/\s/.test(str)) return false; // whitespace -> treat as plain content, not a path
        if (str.length > 2048) return false; // sanity cap
        return /^([./#?]|[a-zA-Z0-9_-]+\/)/.test(str);
      }

      function isRedirectTarget(str) {
        if (!str) return false;
        str = str.trim();
        if (isAbsoluteAllowedUrl(str)) return true;
        if (isRelativePath(str)) return true;
        return false;
      }

      function wouldLoop(target) {
        if (!CONFIG.preventSameHostRedirect) return false;
        if (!isAbsoluteAllowedUrl(target)) return false; // relative paths can't loop by host
        var url = parseUrl(target);
        return url.hostname === window.location.hostname;
      }

      function showContent(text) {
        document.body.textContent = text;
        document.body.style.display = "block";
      }

      function normalizeKey(str) {
        str = (str || "").trim();
        return CONFIG.caseSensitive ? str : str.toLowerCase();
      }

      function handleMatch(issue, homepage) {
        var content = issue[CONFIG.valueField];

        if (CONFIG.mode === "display") {
          showContent(content || "");
          return;
        }

        var canRedirect =
          isRedirectTarget(content) && !wouldLoop(content.trim());

        if (CONFIG.mode === "redirect") {
          window.location.replace(canRedirect ? content.trim() : homepage);
          return;
        }

        // mode === "auto"
        if (canRedirect) {
          window.location.replace(content.trim());
        } else {
          showContent(content || "");
        }
      }

      function fetchPage(pageNum, slugKey, homepage, onDone) {
        if (pageNum > CONFIG.maxPagesToScan) {
          onDone(null);
          return;
        }

        var xhr = new XMLHttpRequest();
        xhr.onload = function () {
          try {
            var issues = JSON.parse(xhr.response);
            if (!Array.isArray(issues)) {
              onDone(null); // e.g. rate-limited / error payload
              return;
            }

            for (var i = 0; i < issues.length; i++) {
              if (normalizeKey(issues[i][CONFIG.keyField]) === slugKey) {
                onDone(issues[i]);
                return;
              }
            }

            if (issues.length < 100) {
              onDone(null); // last page, no match
            } else {
              fetchPage(pageNum + 1, slugKey, homepage, onDone);
            }
          } catch (e) {
            onDone(null);
          }
        };
        xhr.onerror = function () {
          onDone(null);
        };
        xhr.open("GET", GITHUB_ISSUES_LIST + "&page=" + pageNum);
        xhr.send();
      }

      function redirect() {
        var location = window.location;
        var segments = location.pathname.split("/").filter(Boolean);
        var skip = CONFIG.pathSegmentsToSkip;
        var slugSegments = segments.slice(skip);
        var slug = decodeURIComponent(slugSegments.join("/"));
        var homepage =
          location.protocol +
          "//" +
          location.hostname +
          (location.port ? ":" + location.port : "") +
          "/" +
          segments.slice(0, skip).join("/");

        var slugKey = normalizeKey(slug);

        fetchPage(1, slugKey, homepage, function (issue) {
          if (!issue) {
            location.replace(homepage);
            return;
          }
          handleMatch(issue, homepage);
        });
      }

      redirect();
    </script>
  </head>
  <body></body>
</html>