Implement FromRequest for Accept.

lib/src/request/from_request.rs

@@ -5,7 +5,7 @@ use outcome::{self, IntoOutcome};
 use request::Request;
 use outcome::Outcome::*;
 
-use http::{Status, ContentType, Method, Cookies, Session};
+use http::{Status, ContentType, Accept, Method, Cookies, Session};
 use http::uri::URI;
 
 /// Type alias for the `Outcome` of a `FromRequest` conversion.
@@ -220,6 +220,17 @@ impl<'a, 'r> FromRequest<'a, 'r> for Session<'a> {
     }
 }
 
+impl<'a, 'r> FromRequest<'a, 'r> for Accept {
+    type Error = ();
+
+    fn from_request(request: &'a Request<'r>) -> Outcome<Self, Self::Error> {
+        match request.accept() {
+            Some(accept) => Success(accept),
+            None => Forward(())
+        }
+    }
+}
+
 impl<'a, 'r> FromRequest<'a, 'r> for ContentType {
     type Error = ();