Angle brackets should delimit URLs in the body of toots

[zackw]

In https://mastodon.social/@zwol/98982414809236980 I wrote

... the UMass-Amherst Science Fiction Society <http://www.umass.edu/rso/scifi/>'s filk circle ...

The code that scans for URLs in the body of a toot interpreted this as linking to http://www.umass.edu/rso/scifi/%3E's. This Is Wrong. < and > are the official way to delimit URLs in running text, have been ever since URLs were invented. The URL should be understood to end just before the >.

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• I searched or browsed the repo’s other issues to ensure this is not a duplicate.
• This bug happens on a tagged release and not on master (If you're a user, don't worry about this).

[Gargron]

That's part of Markdown syntax but we don't support Markdown. Is there any reason to even write text that way under these circumstances?

[nightpool]

@Gargron markdown doesn't use angle brackets but I'm interested in the answer nonetheless, it feels very weird to use angle brackets to delineate urls in a toot

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On Sun, Apr 8, 2018, 3:54 PM Eugen Rochko ***@***.***> wrote: That's part of Markdown syntax but we don't support Markdown. Is there any reason to even write text that way under these circumstances? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#5654 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAORV0BsVEi9D0u2mB4V4SVuijWfe-t4ks5tmmr2gaJpZM4QaLmJ> .

[Gargron]

@nightpool No, it does. There is the [Text](url) syntax but also <url> syntax. The latter performs linking, because autolinking isn't actually part of Markdown, even though it's done by most implementations anyway.

[zackw]

@nightpool @Gargron Using angle brackets to delimit URLs is not part of Markdown. It's recommended practice according to the official syntax specification for URLs: RFC 3986, Appendix C. It is especially useful for plain-text contexts that auto-linkify URLs but don't implement any other markup that would let you control where the URL ends, such as ... toots.

I gave an example in the original bug description of a sentence that is more natural if you can do this.

[Cassolotl]

Mastodon linkifies URLs, so why would one use triangle brackets?

[zackw]

@Cassolotl Angle brackets are (would be, anyway) useful because it linkifies URLs. The entire point here is to have an explicit way to control where the linkifier thinks the URL ends. Again, see the example in the original bug description.

[Cassolotl]

I see! Thank you. :)

[trwnh]

So this essentially bypasses URL handling logic when calling a specific URL and delimiting it with <>? Although for what it's worth, Mastodon's current behavior is to treat the > as part of the URL, which ends up breaking it!

https://perishablepress.com/stop-using-unsafe-characters-in-urls/

More about “unsafe” characters from RFC1738:

Characters can be unsafe for a number of reasons. The space character is unsafe because significant spaces may disappear and insignificant spaces may be introduced when URLs are transcribed or typeset or subjected to the treatment of word-processing programs. The characters “<” and “>” are unsafe because they are used as the delimiters around URLs in free text; the quote mark (“"”) is used to delimit URLs in some systems.

Probably should also mention that a quote mark (") also ends up breaking the URL in Mastodon. Possibly related issues: #6701, #6031

As an example: Posting "http://trwnh.com/" on Mastodon will hyperlink as http://trwnh.com/", and posting <http://trwnh.com/> on Mastodon will hyperlink as http://trwnh.com/>. The only real workaround currently is to remove the trailing slash in any pasted URLs, but this could also break the URL if the server doesn't know how to handle removing the trailing slash (e.g. if the nginx configuration doesn't include a try_files directive or a regex location block)

[zackw]

So this essentially bypasses URL handling logic when calling a specific URL and delimiting it with <>? Although for what it's worth, Mastodon's current behavior is to treat the > as part of the URL, which ends up breaking it!

I'm not sure what you mean by "bypasses URL handling logic", but the change I'm specifically asking for is to not treat the > as part of the URL.

[trwnh]

@zackw I mean that the proposal implies that the text parser should essentially support wrapping whatever it finds inside <...> in an <a href=""></a> tag -- "URL handling logic" meaning the function that Mastodon uses to determine what is and isn't a URL. It would be problematic to say that > should be explicitly disallowed in URLs, since it's only "unsafe" or "discouraged" -- it's still a valid URL in some cases.

[codl]

> is disallowed in urls, and should be percent-encoded