Reimplement misleading link tagging in new HTML handling code (#3254)

app/javascript/flavours/glitch/components/status/handled_link.tsx

@@ -1,4 +1,4 @@
-import { useCallback } from 'react';
+import { useCallback, useEffect, useRef } from 'react';
 import type { ComponentProps, FC } from 'react';
 
 import classNames from 'classnames';
@@ -7,6 +7,7 @@ import { Link } from 'react-router-dom';
 import type { ApiMentionJSON } from '@/flavours/glitch/api_types/statuses';
 import { useAppSelector } from '@/flavours/glitch/store';
 import type { OnElementHandler } from '@/flavours/glitch/utils/html';
+import { decode as decodeIDNA } from 'flavours/glitch/utils/idna';
 
 export interface HandledLinkProps {
   href: string;
@@ -16,6 +17,94 @@ export interface HandledLinkProps {
   mention?: Pick<ApiMentionJSON, 'id' | 'acct' | 'username'>;
 }
 
+const textMatchesTarget = (text: string, origin: string, host: string) => {
+  return (
+    text === origin ||
+    text === host ||
+    text.startsWith(origin + '/') ||
+    text.startsWith(host + '/') ||
+    'www.' + text === host ||
+    ('www.' + text).startsWith(host + '/')
+  );
+};
+
+export const isLinkMisleading = (link: HTMLAnchorElement) => {
+  const linkTextParts: string[] = [];
+
+  // Reconstruct visible text, as we do not have much control over how links
+  // from remote software look, and we can't rely on `innerText` because the
+  // `invisible` class does not set `display` to `none`.
+
+  const walk = (node: Node) => {
+    if (node instanceof Text) {
+      linkTextParts.push(node.textContent);
+    } else if (node instanceof HTMLElement) {
+      if (node.classList.contains('invisible')) return;
+      for (const child of node.childNodes) {
+        walk(child);
+      }
+    }
+  };
+
+  walk(link);
+
+  const linkText = linkTextParts.join('');
+  const targetURL = new URL(link.href);
+
+  if (targetURL.protocol === 'magnet:') {
+    return !linkText.startsWith('magnet:');
+  }
+
+  if (targetURL.protocol === 'xmpp:') {
+    return !(
+      linkText === targetURL.href || 'xmpp:' + linkText === targetURL.href
+    );
+  }
+
+  // The following may not work with international domain names
+  if (
+    textMatchesTarget(linkText, targetURL.origin, targetURL.host) ||
+    textMatchesTarget(linkText.toLowerCase(), targetURL.origin, targetURL.host)
+  ) {
+    return false;
+  }
+
+  // The link hasn't been recognized, maybe it features an international domain name
+  const hostname = decodeIDNA(targetURL.hostname).normalize('NFKC');
+  const host = targetURL.host.replace(targetURL.hostname, hostname);
+  const origin = targetURL.origin.replace(targetURL.host, host);
+  const text = linkText.normalize('NFKC');
+  return !(
+    textMatchesTarget(text, origin, host) ||
+    textMatchesTarget(text.toLowerCase(), origin, host)
+  );
+};
+
+export const tagMisleadingLink = (link: HTMLAnchorElement) => {
+  try {
+    if (isLinkMisleading(link)) {
+      const url = new URL(link.href);
+      const tag = document.createElement('span');
+      tag.classList.add('link-origin-tag');
+      switch (url.protocol) {
+        case 'xmpp:':
+          tag.textContent = `[${url.href}]`;
+          break;
+        case 'magnet:':
+          tag.textContent = '(magnet)';
+          break;
+        default:
+          tag.textContent = `[${url.host}]`;
+      }
+      link.insertAdjacentText('beforeend', ' ');
+      link.insertAdjacentElement('beforeend', tag);
+    }
+  } catch (e) {
+    // The URL is invalid, remove the href just to be safe
+    if (e instanceof TypeError) link.removeAttribute('href');
+  }
+};
+
 export const HandledLink: FC<HandledLinkProps & ComponentProps<'a'>> = ({
   href,
   text,
@@ -30,6 +119,17 @@ export const HandledLink: FC<HandledLinkProps & ComponentProps<'a'>> = ({
     // eslint-disable-next-line @typescript-eslint/no-unsafe-call, @typescript-eslint/no-unsafe-member-access
     (state) => state.local_settings.get('rewrite_mentions', 'no') as string,
   );
+  const tagLinks = useAppSelector(
+    (state) =>
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-call, @typescript-eslint/no-unsafe-member-access
+      state.local_settings.get('tag_misleading_links', false) as string,
+  );
+
+  const linkRef = useRef<HTMLAnchorElement>(null);
+
+  useEffect(() => {
+    if (tagLinks && linkRef.current) tagMisleadingLink(linkRef.current);
+  }, [tagLinks]);
 
   // Handle hashtags
   if (text.startsWith('#') || prevText?.endsWith('#')) {
@@ -93,6 +193,7 @@ export const HandledLink: FC<HandledLinkProps & ComponentProps<'a'>> = ({
       target='_blank'
       rel='noreferrer noopener'
       translate='no'
+      ref={linkRef}
     >
       {children}
     </a>

app/javascript/flavours/glitch/components/status_content.jsx

@@ -14,70 +14,14 @@ import { Icon } from 'flavours/glitch/components/icon';
 import { Poll } from 'flavours/glitch/components/poll';
 import { identityContextPropShape, withIdentity } from 'flavours/glitch/identity_context';
 import { languages as preloadedLanguages } from 'flavours/glitch/initial_state';
-import { decode as decodeIDNA } from 'flavours/glitch/utils/idna';
 
 import { isModernEmojiEnabled } from '../utils/environment';
 
 import { EmojiHTML } from './emoji/html';
-import { HandledLink } from './status/handled_link';
+import { HandledLink, isLinkMisleading, tagMisleadingLink } from './status/handled_link';
 
 const MAX_HEIGHT = 706; // 22px * 32 (+ 2px padding at the top)
 
-const textMatchesTarget = (text, origin, host) => {
-  return (text === origin || text === host
-          || text.startsWith(origin + '/') || text.startsWith(host + '/')
-          || 'www.' + text === host || ('www.' + text).startsWith(host + '/'));
-};
-
-const isLinkMisleading = (link) => {
-  let linkTextParts = [];
-
-  // Reconstruct visible text, as we do not have much control over how links
-  // from remote software look, and we can't rely on `innerText` because the
-  // `invisible` class does not set `display` to `none`.
-
-  const walk = (node) => {
-    switch (node.nodeType) {
-    case Node.TEXT_NODE:
-      linkTextParts.push(node.textContent);
-      break;
-    case Node.ELEMENT_NODE: {
-      if (node.classList.contains('invisible')) return;
-      const children = node.childNodes;
-      for (let i = 0; i < children.length; i++) {
-        walk(children[i]);
-      }
-      break;
-    }
-    }
-  };
-
-  walk(link);
-
-  const linkText = linkTextParts.join('');
-  const targetURL = new URL(link.href);
-
-  if (targetURL.protocol === 'magnet:') {
-    return !linkText.startsWith('magnet:');
-  }
-
-  if (targetURL.protocol === 'xmpp:') {
-    return !(linkText === targetURL.href || 'xmpp:' + linkText === targetURL.href);
-  }
-
-  // The following may not work with international domain names
-  if (textMatchesTarget(linkText, targetURL.origin, targetURL.host) || textMatchesTarget(linkText.toLowerCase(), targetURL.origin, targetURL.host)) {
-    return false;
-  }
-
-  // The link hasn't been recognized, maybe it features an international domain name
-  const hostname = decodeIDNA(targetURL.hostname).normalize('NFKC');
-  const host = targetURL.host.replace(targetURL.hostname, hostname);
-  const origin = targetURL.origin.replace(targetURL.host, host);
-  const text = linkText.normalize('NFKC');
-  return !(textMatchesTarget(text, origin, host) || textMatchesTarget(text.toLowerCase(), origin, host));
-};
-
 /**
  *
  * @param {any} status
@@ -214,30 +158,7 @@ class StatusContent extends PureComponent {
         link.setAttribute('target', '_blank');
         link.setAttribute('rel', 'noopener nofollow');
 
-        try {
-          if (tagLinks && isLinkMisleading(link)) {
-            // Add a tag besides the link to display its origin
-
-            const url = new URL(link.href);
-            const tag = document.createElement('span');
-            tag.classList.add('link-origin-tag');
-            switch (url.protocol) {
-            case 'xmpp:':
-              tag.textContent = `[${url.href}]`;
-              break;
-            case 'magnet:':
-              tag.textContent = '(magnet)';
-              break;
-            default:
-              tag.textContent = `[${url.host}]`;
-            }
-            link.insertAdjacentText('beforeend', ' ');
-            link.insertAdjacentElement('beforeend', tag);
-          }
-        } catch (e) {
-          // The URL is invalid, remove the href just to be safe
-          if (tagLinks && e instanceof TypeError) link.removeAttribute('href');
-        }
+        if (tagLinks) tagMisleadingLink(link);
       }
     }
   }

app/javascript/flavours/glitch/utils/idna.js

@@ -1,10 +0,0 @@
-import punycode from 'punycode';
-
-const IDNA_PREFIX = 'xn--';
-
-export const decode = domain => {
-  return domain
-    .split('.')
-    .map(part => part.indexOf(IDNA_PREFIX) === 0 ? punycode.decode(part.slice(IDNA_PREFIX.length)) : part)
-    .join('.');
-};

app/javascript/flavours/glitch/utils/idna.ts

@@ -0,0 +1,14 @@
+import punycode from 'punycode/';
+
+const IDNA_PREFIX = 'xn--';
+
+export const decode = (domain: string) => {
+  return domain
+    .split('.')
+    .map((part) =>
+      part.startsWith(IDNA_PREFIX)
+        ? punycode.decode(part.slice(IDNA_PREFIX.length))
+        : part,
+    )
+    .join('.');
+};