add Header trait

src/header/common/if_unmodified_since.rs

@@ -0,0 +1,52 @@
+use http::header;
+
+use header::{Header, HttpDate, IntoHeaderValue};
+use error::ParseError;
+use httpmessage::HttpMessage;
+
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct IfUnmodifiedSince(pub HttpDate);
+
+impl Header for IfUnmodifiedSince {
+    fn name() -> header::HeaderName {
+        header::IF_MODIFIED_SINCE
+    }
+    
+    fn parse<T: HttpMessage>(msg: &T) -> Result<Self, ParseError> {
+        let val = msg.headers().get(Self::name())
+            .ok_or(ParseError::Header)?.to_str().map_err(|_| ParseError::Header)?;
+        Ok(IfUnmodifiedSince(val.parse()?))
+    }
+}
+
+impl IntoHeaderValue for IfUnmodifiedSince {
+    type Error = header::InvalidHeaderValueBytes;
+
+    fn try_into(self) -> Result<header::HeaderValue, Self::Error> {
+        self.0.try_into()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use time::Tm;
+    use test::TestRequest;
+    use httpmessage::HttpMessage;
+    use super::HttpDate;
+    use super::IfUnmodifiedSince;
+
+    fn date() -> HttpDate {
+        Tm {
+            tm_nsec: 0, tm_sec: 37, tm_min: 48, tm_hour: 8,
+            tm_mday: 7, tm_mon: 10, tm_year: 94,
+            tm_wday: 0, tm_isdst: 0, tm_yday: 0, tm_utcoff: 0}.into()
+    }
+
+    #[test]
+    fn test_if_mod_since() {
+        let req = TestRequest::with_hdr(IfUnmodifiedSince(date())).finish();
+        let h = req.get::<IfUnmodifiedSince>().unwrap();
+        assert_eq!(h.0, date());
+    }
+}