ruma_events/room/message/
sanitize.rs

1//! Convenience methods and types to sanitize text messages.
2
3/// Remove the [rich reply] fallback of the given plain text string.
4///
5/// [rich reply]: https://spec.matrix.org/latest/client-server-api/#rich-replies
6pub fn remove_plain_reply_fallback(mut s: &str) -> &str {
7    // A reply fallback must begin with a mention of the original sender between `<` and `>`, and
8    // emotes add `*` as a prefix. If there is no newline, removing the detected fallback would
9    // result in an empty string.
10    if (!s.starts_with("> <") && !s.starts_with("> * <")) || !s.contains('\n') {
11        return s;
12    }
13
14    while s.starts_with("> ") {
15        if let Some((_line, rest)) = s.split_once('\n') {
16            s = rest;
17        } else {
18            return "";
19        }
20    }
21
22    // Strip the first line after the fallback if it is empty.
23    if let Some(rest) = s.strip_prefix('\n') {
24        rest
25    } else {
26        s
27    }
28}
29
30#[cfg(test)]
31mod tests {
32    use super::remove_plain_reply_fallback;
33
34    #[test]
35    fn remove_plain_reply() {
36        assert_eq!(
37            remove_plain_reply_fallback("No reply here\nJust a simple message"),
38            "No reply here\nJust a simple message"
39        );
40
41        assert_eq!(
42            remove_plain_reply_fallback(
43                "> <@user:notareal.hs> Replied to on\n\
44                 > two lines\n\
45                 \n\
46                 \n\
47                 This is my reply"
48            ),
49            "\nThis is my reply"
50        );
51
52        assert_eq!(remove_plain_reply_fallback("\n> Not on first line"), "\n> Not on first line");
53
54        assert_eq!(
55            remove_plain_reply_fallback("> <@user:notareal.hs> Previous message\n\n> New quote"),
56            "> New quote"
57        );
58    }
59}