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feat(chat): warn before opening a link from a message - #1555
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A link in a chat message opens whatever URL the sender typed, straight into the browser. A drainer site reached that way gets no domain check first. The chat transcript now provides a UriHandler that runs each LinkAnnotation.Url through one host check. A host that exactly matches the first-party list opens directly; anything else shows "You're leaving Flipcash" with the host lowercased and in punycode, Cancel as the primary button and a text-only Open Link as the secondary. The list moves from LinkCardClassifier.CARD_HOSTS to core so the card classifier and the warning read the same set. Links the app opens on purpose, such as token socials, terms and the cash card, don't go through the check.
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A link in a chat message opens whatever URL the sender typed, straight into the browser. A drainer site reached that way gets no domain check first. This adds the iOS "You're leaving Flipcash" alert in front of chat message links whose host isn't first-party.
How it works
classifyLink(url)returns first-party or external-with-host. A host passes only on an exact match against the first-party list, soevilflipcash.comandflipcash.com.evil.tldwarn. The displayed host is lowercased and run throughIDN.toASCII, so a lookalike with a Cyrillic "а" shows asxn--.... A URL with no host, such asmailto:, shows its scheme instead.MessengerScreenprovidesExternalLinkUriHandlerasLocalUriHandleraroundMessageList, which covers theLinkAnnotation.Urlspans in message text. Links the app sends the user to on purpose, like token socials, terms and the cash card, open as before.LinkCardClassifier.CARD_HOSTSnow reads the same list from core, so the card classifier and the warning can't drift apart.Copy
The alert matches iOS: title "You're leaving Flipcash", body "This link opens {host}. Flipcash will never ask for your Access Key on a website", Cancel as the primary button, a text-only Open Link as the secondary. "Access Key" is the term the app already uses for the recovery phrase. iOS bolds the host; here it's plain text, since the alert body takes a
String.Tests
ExternalLinksTestcovers each first-party host, the lookalike and punycode hosts, userinfo (flipcash.com@evil.com) and backslash URLs, which are checked against the host the browser would open.LinkCardClassifierTeststill passes against the shared list.