Mastodawn

I wrote hacky tampermonkey script to fix Lemmy instance links. Any advice?

https://sh.itjust.works/post/5563197

I wrote hacky tampermonkey script to fix Lemmy instance links. Any advice? - sh.itjust.works

Read this post [https://sh.itjust.works/post/5556588] 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!

Andy Sep 21, 2023

I just posted this on the post you linked, but yeah I am hardcoding a list of instances into my solution. Here’s my comment, copied:

I’m using the Firefox addon Redirector, and one of my rules there redirects community links using regex. I keep adding to the pattern as I encounter more instances. Currently it’s:

Pattern: https://(lemdro\.id|lemmy\.run|beehaw\.org|lemmy\.ml|sh\.itjust\.works|lemmy\.fmhy\.ml|lemmy\.dbzer0\.com|lemmy\.world|sopuli\.xyz|lemmy\.kde\.social|lemmygrad\.ml|mander\.xyz|lemmy\.ca|zerobytes\.monster)/c/(.*) Redirect to: https://programming.dev/c/$2@$1

Redirector – Get this Extension for 🦊 Firefox (en-US)

Download Redirector for Firefox. Automatically redirects to user-defined urls on certain pages

TerrorBite 🦁Sep 21, 2023

@Andy @BeanCounter Given how many of these start with "Lemmy" you could simplify this to:

`https://(lemmy\.(?:run|(?:fmhy\.)?ml|dbzer0\.com|world|kde\.social|ca)|lemmygrad\.ml|lemdro\.id|beehaw\.org|sh\.itjust\.works|(?:sopuli|mander)\.xyz|zerobytes\.monster)/c/(.*)`

Or just assume that anything matching `https://(lemmy\.[^/]+)/c/(.*)` is a Lemmy server, which will probably be correct.

Edit: some kind of interaction between Mastodon and Lemmy has doubled all my backslashes. That is not intentional.

ezchili Sep 21, 2023

Never use regex on URLs, make a list of hostnames and use the browser’s URL api to extract hostnames then match against the list

Andy Sep 21, 2023

Can you provide an example URL that breaks this solution?

ezchili Sep 21, 2023

Sure!

user:[email protected]:80 is a valid url to lemdro.id and should match but will not

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

Lemdro.id

A place for tech enthusiasts and more!

Andy Sep 21, 2023

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

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.

Lemdro.id

A place for tech enthusiasts and more!

ezchili Sep 22, 2023

Lmao ok

Andy Sep 22, 2023

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.

ezchili Sep 22, 2023

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

regex101: build, test, and debug regex

Regular expression tester with syntax highlighting, explanation, cheat sheet for PHP/PCRE, Python, GO, JavaScript, Java, C#/.NET, Rust.

regex101

Andy Sep 22, 2023

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.

Turun Sep 21, 2023

feddit.de is missing.

Cynber Sep 21, 2023

We’re actually working on a browser extension for this! It currently supports both communities and posts

[email protected]

We ran into the same issue, federated sites are hard to work with. Right now, the extension has it so that a user needs to right click on a link to be redirected. That way the user can choose which links get redirected, and there’s no chance of accidentally redirecting the wrong thing.

There are other solutions (using the API for example), but they seemed to slow the browser down too much. Another proposed feature that hasn’t been implemented yet was to redirect when holding down a key (when holding down “r”, try to redirect the link).

Feel free to take a look, try it, and you can totally contribute code. It’s all open source and we’ve tried to keep the code simple and easy to verify/contribute.

BeanCounter Sep 21, 2023

I am not that familiar with browser extensions dev enough to contribute rn but that looks awesome. If there’s any chance, I’ll definitely contribute!

Cynber Sep 21, 2023

Sounds good! This was my first dive into browser extensions as well. It’s not too bad once you go over the basics. If you give it a try, see the contributing page on the repo’s wiki for some resources on how to get started with browser extensions.

A super short summary is:

manifest.json is the entry point, it links to HTML files (which represent things like the popup, sidebar) and scripts (which do most of the work)
the background script runs all the time (see background.js), and the content scripts run on specific pages (ex. There’s one for Lemmy community pages, one for error pages)

If you DO give it a try, we were part way through migrating features from the LemmyTools userscript and that might be a good place to start. I wasn’t familiar with userscripts so I didn’t make much progress, and can’t get back to it for a little while. The issues page of the repo should have LemmyTools related features tagged. If any details are missing, let me know and I’ll add them in :)

abbadon420 Sep 21, 2023

“Try to take over the world” sounds a bit evil, you might wanna try something like “Improve lemmy for the betterment of mankind”

smpl Sep 21, 2023

You could check if a domain contains a lemmy instance by fetching /.well-known/nodeinfo, but it’s bad netiquette to hammer sites with requests and could get users blocked. If you were to do it I’d make sure it cached the lookups in IndexedDB, localStorage or just using Cache API. I’m unsure how well any of the APIs works with UserScripts.

IndexedDB API - Web APIs | MDN

IndexedDB is a low-level API for client-side storage of significant amounts of structured data, including files/blobs. This API uses indexes to enable high-performance searches of this data. While Web Storage is useful for storing smaller amounts of data, it is less useful for storing larger amounts of structured data. IndexedDB provides a solution. This is the main landing page for MDN's IndexedDB coverage — here we provide links to the full API reference and usage guides, browser support details, and some explanation of key concepts.

MDN Web Docs

Nerd02 Sep 21, 2023

Interesting idea. I’m currently working on a Lemmy-ui fork for my instance and including a feature of this kind in the frontend would be kinda nice.

I’ll bookmark this and come back if I ever get to it.

nephs Sep 21, 2023

Why not contribute to the upstream?