feat: Add HeaderExt trait

src/ext.rs

@@ -0,0 +1,34 @@
+use crate::{Header, HeaderValue};
+
+/// An external trait adding helper methods to types which implement [`Header`] trait.
+pub trait HeaderExt: Header + self::sealed::Sealed {
+    /// Encode this [`Header`] to [`HeaderValue`].
+    fn encode_to_value(&self) -> HeaderValue;
+}
+
+impl<H> HeaderExt for H
+where
+    H: Header + self::sealed::Sealed,
+{
+    fn encode_to_value(&self) -> HeaderValue {
+        let mut container = Vec::with_capacity(1);
+        self.encode(&mut container);
+        container.remove(0)
+    }
+}
+
+mod sealed {
+    pub trait Sealed {}
+    impl<H: crate::Header> Sealed for H {}
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn encode_header() {
+        let header_value = crate::AcceptRanges::bytes().encode_to_value();
+        assert_eq!(header_value, HeaderValue::from_static("bytes"));
+    }
+}

src/lib.rs

@@ -93,7 +93,9 @@ pub use http::header::{HeaderName, HeaderValue};
 #[macro_use]
 mod util;
 mod common;
+mod ext;
 mod map_ext;
 
 pub use self::common::*;
+pub use self::ext::HeaderExt;
 pub use self::map_ext::HeaderMapExt;