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4chan bypass derefer link interstitial

Bypasses the derefer link interstitial for external links on 4chan

  1. // ==UserScript==
  2. // @name        4chan bypass derefer link interstitial
  3. // @namespace   b3vwq7gg90yplbelsnvz
  4. // @match       https://boards.4chan.org/*
  5. // @match       https://boards.4channel.org/*
  6. // @match       https://sys.4chan.org/derefer?*
  7. // @match       https://sys.4channel.org/derefer?*
  8. // @grant       none
  9. // @version     1.0.1
  10. // @description Bypasses the derefer link interstitial for external links on 4chan
  11. // @run-at      document-start
  12. // @insert-into content
  13. // @license     MIT
  14. // ==/UserScript==
  15.  
  16. (function () {
  17. 	"use strict";
  18.  
  19. 	if (location.hostname.startsWith("sys.4chan")) {
  20. 		// Derefer page (somehow), redirect immediately
  21. 		const real = new URL(new URLSearchParams(location.search).get("url"));
  22.  
  23. 		if (real && (real.protocol === "https:" || real.protocol === "http:")) {
  24. 			const link = document.createElement("a");
  25. 			link.rel = "noopener";
  26. 			link.referrerPolicy = "no-referrer";
  27. 			// Hack fix: 4chan fucks up by double-encoding ampersands
  28. 			link.href = String(real).replaceAll("&", "&");
  29. 			link.click();
  30. 		}
  31. 	} else {
  32. 		// Board page, fix linkified links
  33. 		const dereferLink = "//" + location.host.replace("boards.4chan", "sys.4chan") + "/derefer?url=";
  34. 		const derefSelector = `a.linkified[href^="${dereferLink}"]`;
  35.  
  36. 		document.addEventListener("4chanParsingDone", (ev) => {
  37. 			const tid = ev.detail?.threadId;
  38. 			let context;
  39.  
  40. 			if (tid) {
  41. 				context = document.getElementById(`t${tid}`);
  42. 			}
  43.  
  44. 			// If we don't find the thread for some reason,
  45. 			// just scan the entire page instead idk
  46. 			if (!context) {
  47. 				context = document.body;
  48. 			}
  49.  
  50.  
  51. 			for (const link of context.querySelectorAll(derefSelector)) {
  52. 				let real;
  53.  
  54. 				try {
  55. 					// Throws if invalid URL.
  56. 					// Use textContent instead of the url parameter
  57. 					// because that might have double encoded ampersands
  58. 					real = new URL(link.textContent);
  59. 				} catch {
  60. 					continue;
  61. 				}
  62.  
  63. 				if (real.protocol === "https:" || real.protocol === "http:") {
  64. 					link.relList.add("noopener");
  65. 					link.referrerPolicy = "no-referrer";
  66. 					link.href = real;
  67. 				}
  68. 			}
  69. 		});
  70. 	}
  71. })();