identifiers: Add host and is_ip_literal methods to ServerName

Co-authored-by: Timo Kösters <timo@koesters.xyz>

crates/ruma-identifiers/CHANGELOG.md

@@ -12,6 +12,10 @@ Breaking changes:
 * Rename `RoomVersionId::Version{X}` variants to `RoomVersionId::V{X}`
 * Rename `RoomIdOrAliasId` to `RoomOrAliasId`
 
+Improvements:
+
+* Add `host` and `is_ip_literal` methods to `ServerName`
+
 Bug fixes:
 
 * Properly validate localpart when building a `UserId` via `parse_with_server_name` (and its

crates/ruma-identifiers/src/server_name.rs

@@ -1,12 +1,37 @@
 //! Matrix-spec compliant server names.
 
+use std::net::Ipv4Addr;
+
 /// A Matrix-spec compliant server name.
+///
+/// It consists of a host and an optional port (separated by a colon if present).
 #[repr(transparent)]
 #[derive(PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct ServerName(str);
 
 opaque_identifier_validated!(ServerName, ruma_identifiers_validation::server_name::validate);
 
+impl ServerName {
+    /// Returns the host of the server name.
+    ///
+    /// That is: Return the part of the server name before `:<port>` or the full server name if
+    /// there is no port.
+    pub fn host(&self) -> &str {
+        if let Some(end_of_ipv6) = self.0.find(']') {
+            &self.0[..=end_of_ipv6]
+        } else {
+            // It's not ipv6, so ':' means the port starts
+            let end_of_host = self.0.find(':').unwrap_or(self.0.len());
+            &self.0[..end_of_host]
+        }
+    }
+
+    /// Returns true if and only if the server name is an IPv4 or IPv6 address.
+    pub fn is_ip_literal(&self) -> bool {
+        self.host().parse::<Ipv4Addr>().is_ok() || self.0.starts_with('[')
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use std::convert::TryFrom;
@@ -68,4 +93,46 @@ mod tests {
     fn dns_name_with_invalid_port() {
         assert!(<&ServerName>::try_from("matrix.org:hello").is_err());
     }
+
+    #[test]
+    fn parse_ipv4_host() {
+        let server_name = <&ServerName>::try_from("127.0.0.1").unwrap();
+        assert!(server_name.is_ip_literal());
+        assert_eq!(server_name.host(), "127.0.0.1");
+    }
+
+    #[test]
+    fn parse_ipv4_host_and_port() {
+        let server_name = <&ServerName>::try_from("1.1.1.1:12000").unwrap();
+        assert!(server_name.is_ip_literal());
+        assert_eq!(server_name.host(), "1.1.1.1");
+    }
+
+    #[test]
+    fn parse_ipv6() {
+        let server_name = <&ServerName>::try_from("[::1]").unwrap();
+        assert!(server_name.is_ip_literal());
+        assert_eq!(server_name.host(), "[::1]");
+    }
+
+    #[test]
+    fn parse_ipv6_with_port() {
+        let server_name = <&ServerName>::try_from("[1234:5678::abcd]:5678").unwrap();
+        assert!(server_name.is_ip_literal());
+        assert_eq!(server_name.host(), "[1234:5678::abcd]");
+    }
+
+    #[test]
+    fn parse_dns_name() {
+        let server_name = <&ServerName>::try_from("example.com").unwrap();
+        assert!(!server_name.is_ip_literal());
+        assert_eq!(server_name.host(), "example.com");
+    }
+
+    #[test]
+    fn parse_dns_name_with_port() {
+        let server_name = <&ServerName>::try_from("ruma.io:8080").unwrap();
+        assert!(!server_name.is_ip_literal());
+        assert_eq!(server_name.host(), "ruma.io");
+    }
 }