1 files changed, 73 insertions, 0 deletions
diff --git a/internals/src/bind/idna.rs b/internals/src/bind/idna.rs
new file mode 100644
index 0000000..7b82d69
--- /dev/null
+++ b/internals/src/bind/idna.rs
@@ -0,0 +1,73 @@
+use soft_ascii_string::SoftAsciiString;
+use idna;
+
+use ::error::{EncodingError, EncodingErrorKind};
+
+
+/// uses puny code on given domain to return a ascii representation
+///
+/// # Implementation Detail
+/// this function uses `idna::domain_to_ascii`, see the
+/// `idna` crates documentation fore more details on how
+/// exactly all edgecase are handled
+///
+/// # Note
+/// that this function does not validate the domain, e.g.
+/// if you puny code the domain `"this seems\0so;wrong"` it
+/// will return `Ok("this seems\0so;wrong")`
+///
+pub fn puny_code_domain<R: AsRef<str>>(domain: R)
+    -> Result<SoftAsciiString, EncodingError>
+{
+    _puny_code_domain(domain.as_ref())
+}
+
+fn _puny_code_domain(domain: &str)
+    -> Result<SoftAsciiString, EncodingError>
+{
+    match idna::domain_to_ascii(domain) {
+        Ok(asciified) => {
+            //SAFE: well we converted it to ascii, so it's ascii
+            Ok(SoftAsciiString::from_unchecked(asciified))
+        },
+        Err(_non_informative_err) => {
+            Err(EncodingErrorKind::NotEncodable { encoding: "punycode" }.into())
+        }
+    }
+}
+
+
+#[cfg(test)]
+mod test {
+    use idna;
+    use super::puny_code_domain;
+
+    #[test]
+    fn idna_does_not_validate() {
+        let domain = "this seems\0so;wrong";
+        assert_eq!(
+            domain.to_owned(),
+            assert_ok!( idna::domain_to_ascii(domain) )
+        );
+    }
+
+    #[test]
+    fn nop_puny_code() {
+        let domain = "is_ascii.notadomain";
+
+        let encoded = assert_ok!( puny_code_domain( domain ) );
+        assert_eq!(
+            &*encoded,
+            "is_ascii.notadomain"
+        );
+    }
+    #[test]
+    fn puny_code_ascii_mail() {
+        let domain = "nöt_ascii.ü";
+        let encoded = assert_ok!( puny_code_domain(domain) );
+        assert_eq!(
+            &*encoded,
+            "xn--nt_ascii-n4a.xn--tda"
+        );
+    }
+}
+\ No newline at end of file