Read this post and wrote a simple Tampermonkey script as a solution.

// ==UserScript==
// @name         Fix community link
// @version      0.1
// @description  try to take over the world!
// @match        https://sh.itjust.works/post/*
// ==/UserScript==

(function() {
    'use strict';
    const postLinks = document.getElementById("postContent").querySelectorAll("a:not(.community-link)") // get every links that is NOT a community link

    const fixLink = (aTags) => {
        for (let aTag of aTags) {
            const isCommunityLink = aTag.pathname.startsWith("/c/");
            aTag.href = isCommunityLink?aTag.pathname + "@" + aTag.host:aTag.href
        };
    }

    fixLink(postLinks)

    const comments = document.getElementsByClassName("comment-content");

    for (let comment of comments) {
        let commentLinks = comment.querySelectorAll("a:not(.community-link)");
        fixLink(commentLinks)
    }
})();

Any advice? I especially hate the fact that the way to check if it’s a link for lemmy community is through pathname but I thought there’s can’t be a real solution besides listing all the lemmy instances or actually making a request somehow.

Any inputs are welcome!

  • @[email protected]
    1•2 years ago

    HtTpS://user:[email protected]:443 is a valid url to lemdro.id and should match but will not

    Well that one:

    • technically shouldn’t match, because it’s not a community URL
    • is not the form I expect and want to be using for this case
    • may actually work (if it were a real community link, which again, it’s not), because after authentication I think the browser strips the credentials

    Http://maliciouswebsite.to/?q=http://lemdro.id will match but should not

    No, it does not match.

    AFAICT, this solution is working properly, but if you can find a URL that breaks it, please let me know.

    • @[email protected]
      1•2 years ago

      Lmao ah yes, one of those

      If you’re not convinced with this you never will

      You can just wrap your var with “new URL()” and have something faster, correct and easier to read, but I’m guessing you’ll change your ways silently in a few years when you’ve forgotten about this interaction and managed to convince yourself it was your own idea!

      Until then i guess you can add /c/whatev at the end of my two examples and find something else to criticize and decide not to support

      • @[email protected]
        1•2 years ago

        I’m not trying to be combative, I’m trying to understand. I’d like to see the failure in action so I can appreciate and pursue the proposed solution.

        But when I added the community bit to the first URL, the browser resolved it and stripped the credentials, so the resulting URL matched. But the example credentials weren’t real so it’s not a great test; if there’s an real example I can test, please share it. Though I don’t see why I’d auth to an instance just to view it from a different instance.

        When I added the community bit to the second URL, it was not a match, as it shouldn’t be. The pattern must match the entire URL.

        • @[email protected]
          1•2 years ago

          You can find it in action on regex101

          Just the port is enough to make it fail but this is not even the point

          The sheer number of things you have to take into account to properly parse a URL should convince you to not use regexes for it

          • @[email protected]
            1•2 years ago

            I meant to communicate that the Redirector addon uses the given pattern to see if the entire URL string matches, not part of it. So the malicious URL does not match.

            I’m wondering if there’s a real URL for which the Redirector approach will not work.