diff --git a/src/header/common/accept.rs b/src/header/common/accept.rs
index bfa847ff..3617f6ee 100644
--- a/src/header/common/accept.rs
+++ b/src/header/common/accept.rs
@@ -1,7 +1,9 @@
-use header::{Header, HeaderFormat};
-use std::fmt::{mod, Show};
-use std::str::from_utf8;
-use mime::Mime;
+use std::fmt;
+
+use header;
+use header::shared;
+
+use mime;
 
 /// The `Accept` header.
 ///
@@ -14,60 +16,53 @@ use mime::Mime;
 /// ```
 /// # use hyper::header::Headers;
 /// # use hyper::header::common::Accept;
+/// # use hyper::header::shared::qitem;
 /// use hyper::mime::Mime;
 /// use hyper::mime::TopLevel::Text;
 /// use hyper::mime::SubLevel::{Html, Xml};
 /// # let mut headers = Headers::new();
-/// headers.set(Accept(vec![ Mime(Text, Html, vec![]), Mime(Text, Xml, vec![]) ]));
+/// headers.set(Accept(vec![
+///     qitem(Mime(Text, Html, vec![])),
+///     qitem(Mime(Text, Xml, vec![])) ]));
 /// ```
 #[deriving(Clone, PartialEq, Show)]
-pub struct Accept(pub Vec<Mime>);
+pub struct Accept(pub Vec<shared::QualityItem<mime::Mime>>);
 
-deref!(Accept -> Vec<Mime>);
+deref!(Accept -> Vec<shared::QualityItem<mime::Mime>>);
 
-impl Header for Accept {
+impl header::Header for Accept {
     fn header_name(_: Option<Accept>) -> &'static str {
         "Accept"
     }
 
     fn parse_header(raw: &[Vec<u8>]) -> Option<Accept> {
-        let mut mimes: Vec<Mime> = vec![];
-        for mimes_raw in raw.iter() {
-            match from_utf8(mimes_raw.as_slice()) {
-                Ok(mimes_str) => {
-                    for mime_str in mimes_str.split(',') {
-                        match mime_str.trim().parse() {
-                            Some(mime) => mimes.push(mime),
-                            None => return None
-                        }
-                    }
-                },
-                Err(_) => return None
-            };
-        }
-
-        if !mimes.is_empty() {
-            Some(Accept(mimes))
-        } else {
-            // Currently is just a None, but later it can be Accept for */*
-            None
-        }
+        // TODO: Return */* if no value is given.
+        shared::from_comma_delimited(raw).map(Accept)
     }
 }
 
-impl HeaderFormat for Accept {
+impl header::HeaderFormat for Accept {
     fn fmt_header(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        let Accept(ref value) = *self;
-        let last = value.len() - 1;
-        for (i, mime) in value.iter().enumerate() {
-            try!(mime.fmt(fmt));
-            if i < last {
-                try!(", ".fmt(fmt));
-            }
-        }
-        Ok(())
+        shared::fmt_comma_delimited(fmt, self[])
     }
 }
 
 bench_header!(bench, Accept, { vec![b"text/plain; q=0.5, text/html".to_vec()] });
 
+#[test]
+fn test_parse_header_no_quality() {
+    let a: Accept = header::Header::parse_header([b"text/plain; charset=utf-8".to_vec()].as_slice()).unwrap();
+    let b = Accept(vec![
+        shared::QualityItem{item: mime::Mime(mime::TopLevel::Text, mime::SubLevel::Plain, vec![(mime::Attr::Charset, mime::Value::Utf8)]), quality: 1f32},
+    ]);
+    assert_eq!(a, b);
+}
+
+#[test]
+fn test_parse_header_with_quality() {
+    let a: Accept = header::Header::parse_header([b"text/plain; charset=utf-8; q=0.5".to_vec()].as_slice()).unwrap();
+    let b = Accept(vec![
+        shared::QualityItem{item: mime::Mime(mime::TopLevel::Text, mime::SubLevel::Plain, vec![(mime::Attr::Charset, mime::Value::Utf8)]), quality: 0.5f32},
+    ]);
+    assert_eq!(a, b);
+}
diff --git a/src/header/common/accept_encoding.rs b/src/header/common/accept_encoding.rs
new file mode 100644
index 00000000..622de977
--- /dev/null
+++ b/src/header/common/accept_encoding.rs
@@ -0,0 +1,39 @@
+use std::fmt;
+
+use header;
+use header::shared;
+
+/// The `Accept-Encoding` header
+///
+/// The `Accept-Encoding` header can be used by clients to indicate what
+/// response encodings they accept.
+#[deriving(Clone, PartialEq, Show)]
+pub struct AcceptEncoding(pub Vec<shared::QualityItem<shared::Encoding>>);
+
+deref!(AcceptEncoding -> Vec<shared::QualityItem<shared::Encoding>>);
+
+impl header::Header for AcceptEncoding {
+    fn header_name(_: Option<AcceptEncoding>) -> &'static str {
+        "AcceptEncoding"
+    }
+
+    fn parse_header(raw: &[Vec<u8>]) -> Option<AcceptEncoding> {
+        shared::from_comma_delimited(raw).map(AcceptEncoding)
+    }
+}
+
+impl header::HeaderFormat for AcceptEncoding {
+    fn fmt_header(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        shared::fmt_comma_delimited(fmt, self[])
+    }
+}
+
+#[test]
+fn test_parse_header() {
+    let a: AcceptEncoding = header::Header::parse_header([b"gzip;q=1.0, identity; q=0.5".to_vec()].as_slice()).unwrap();
+    let b = AcceptEncoding(vec![
+        shared::QualityItem{item: shared::Gzip, quality: 1f32},
+        shared::QualityItem{item: shared::Identity, quality: 0.5f32},
+    ]);
+    assert_eq!(a, b);
+}
diff --git a/src/header/common/allow.rs b/src/header/common/allow.rs
index 07e17cd2..0efad670 100644
--- a/src/header/common/allow.rs
+++ b/src/header/common/allow.rs
@@ -1,7 +1,7 @@
 use header::{Header, HeaderFormat};
 use method::Method;
 use std::fmt::{mod};
-use super::util::{from_comma_delimited, fmt_comma_delimited};
+use header::shared::util::{from_comma_delimited, fmt_comma_delimited};
 
 /// The `Allow` header.
 /// See also https://tools.ietf.org/html/rfc7231#section-7.4.1
@@ -46,4 +46,3 @@ mod tests {
 }
 
 bench_header!(bench, Allow, { vec![b"OPTIONS,GET,PUT,POST,DELETE,HEAD,TRACE,CONNECT,PATCH,fOObAr".to_vec()] });
-
diff --git a/src/header/common/cache_control.rs b/src/header/common/cache_control.rs
index 304c01db..8c309dff 100644
--- a/src/header/common/cache_control.rs
+++ b/src/header/common/cache_control.rs
@@ -1,7 +1,7 @@
 use std::fmt;
 use std::str::FromStr;
 use header::{Header, HeaderFormat};
-use super::util::{from_one_comma_delimited, fmt_comma_delimited};
+use header::shared::util::{from_one_comma_delimited, fmt_comma_delimited};
 
 /// The Cache-Control header.
 #[deriving(PartialEq, Clone, Show)]
diff --git a/src/header/common/connection.rs b/src/header/common/connection.rs
index 2ae9b972..ad2ce2b6 100644
--- a/src/header/common/connection.rs
+++ b/src/header/common/connection.rs
@@ -1,7 +1,7 @@
 use header::{Header, HeaderFormat};
 use std::fmt::{mod, Show};
 use std::str::FromStr;
-use super::util::{from_comma_delimited, fmt_comma_delimited};
+use header::shared::util::{from_comma_delimited, fmt_comma_delimited};
 
 pub use self::ConnectionOption::{KeepAlive, Close, ConnectionHeader};
 
diff --git a/src/header/common/content_length.rs b/src/header/common/content_length.rs
index 32957b97..3637d02b 100644
--- a/src/header/common/content_length.rs
+++ b/src/header/common/content_length.rs
@@ -1,7 +1,7 @@
 use std::fmt::{mod, Show};
 
 use header::{Header, HeaderFormat};
-use super::util::from_one_raw_str;
+use header::shared::util::from_one_raw_str;
 
 /// The `Content-Length` header.
 ///
diff --git a/src/header/common/content_type.rs b/src/header/common/content_type.rs
index 4b26dac5..d07c3542 100644
--- a/src/header/common/content_type.rs
+++ b/src/header/common/content_type.rs
@@ -1,6 +1,6 @@
 use header::{Header, HeaderFormat};
 use std::fmt::{mod, Show};
-use super::util::from_one_raw_str;
+use header::shared::util::from_one_raw_str;
 use mime::Mime;
 
 /// The `Content-Type` header.
diff --git a/src/header/common/date.rs b/src/header/common/date.rs
index a33d16a4..9398cefe 100644
--- a/src/header/common/date.rs
+++ b/src/header/common/date.rs
@@ -2,7 +2,8 @@ use std::fmt::{mod, Show};
 use std::str::FromStr;
 use time::Tm;
 use header::{Header, HeaderFormat};
-use super::util::{from_one_raw_str, tm_from_str};
+use header::shared::util::from_one_raw_str;
+use header::shared::time::tm_from_str;
 
 // Egh, replace as soon as something better than time::Tm exists.
 /// The `Date` header field.
@@ -41,4 +42,3 @@ impl FromStr for Date {
 bench_header!(imf_fixdate, Date, { vec![b"Sun, 07 Nov 1994 08:48:37 GMT".to_vec()] });
 bench_header!(rfc_850, Date, { vec![b"Sunday, 06-Nov-94 08:49:37 GMT".to_vec()] });
 bench_header!(asctime, Date, { vec![b"Sun Nov  6 08:49:37 1994".to_vec()] });
-
diff --git a/src/header/common/etag.rs b/src/header/common/etag.rs
index bddbf02e..3bdd3a6b 100644
--- a/src/header/common/etag.rs
+++ b/src/header/common/etag.rs
@@ -1,6 +1,6 @@
 use header::{Header, HeaderFormat};
 use std::fmt::{mod};
-use super::util::from_one_raw_str;
+use header::shared::util::from_one_raw_str;
 
 /// The `Etag` header.
 ///
diff --git a/src/header/common/expires.rs b/src/header/common/expires.rs
index f9dfe35c..4f160ded 100644
--- a/src/header/common/expires.rs
+++ b/src/header/common/expires.rs
@@ -2,7 +2,8 @@ use std::fmt::{mod, Show};
 use std::str::FromStr;
 use time::Tm;
 use header::{Header, HeaderFormat};
-use super::util::{from_one_raw_str, tm_from_str};
+use header::shared::util::from_one_raw_str;
+use header::shared::time::tm_from_str;
 
 /// The `Expires` header field.
 #[deriving(Copy, PartialEq, Clone)]
@@ -40,4 +41,3 @@ impl FromStr for Expires {
 bench_header!(imf_fixdate, Expires, { vec![b"Sun, 07 Nov 1994 08:48:37 GMT".to_vec()] });
 bench_header!(rfc_850, Expires, { vec![b"Sunday, 06-Nov-94 08:49:37 GMT".to_vec()] });
 bench_header!(asctime, Expires, { vec![b"Sun Nov  6 08:49:37 1994".to_vec()] });
-
diff --git a/src/header/common/host.rs b/src/header/common/host.rs
index 3f14d658..7298fa51 100644
--- a/src/header/common/host.rs
+++ b/src/header/common/host.rs
@@ -1,7 +1,7 @@
 use header::{Header, HeaderFormat};
 use Port;
 use std::fmt::{mod, Show};
-use super::util::from_one_raw_str;
+use header::shared::util::from_one_raw_str;
 
 /// The `Host` header.
 ///
diff --git a/src/header/common/if_modified_since.rs b/src/header/common/if_modified_since.rs
index 850e3dff..a462ed54 100644
--- a/src/header/common/if_modified_since.rs
+++ b/src/header/common/if_modified_since.rs
@@ -2,7 +2,8 @@ use std::fmt::{mod, Show};
 use std::str::FromStr;
 use time::Tm;
 use header::{Header, HeaderFormat};
-use super::util::{from_one_raw_str, tm_from_str};
+use header::shared::util::from_one_raw_str;
+use header::shared::time::tm_from_str;
 
 /// The `If-Modified-Since` header field.
 #[deriving(Copy, PartialEq, Clone)]
@@ -40,4 +41,3 @@ impl FromStr for IfModifiedSince {
 bench_header!(imf_fixdate, IfModifiedSince, { vec![b"Sun, 07 Nov 1994 08:48:37 GMT".to_vec()] });
 bench_header!(rfc_850, IfModifiedSince, { vec![b"Sunday, 06-Nov-94 08:49:37 GMT".to_vec()] });
 bench_header!(asctime, IfModifiedSince, { vec![b"Sun Nov  6 08:49:37 1994".to_vec()] });
-
diff --git a/src/header/common/last_modified.rs b/src/header/common/last_modified.rs
index 5606f093..5369ae4d 100644
--- a/src/header/common/last_modified.rs
+++ b/src/header/common/last_modified.rs
@@ -2,7 +2,8 @@ use std::fmt::{mod, Show};
 use std::str::FromStr;
 use time::Tm;
 use header::{Header, HeaderFormat};
-use super::util::{from_one_raw_str, tm_from_str};
+use header::shared::util::from_one_raw_str;
+use header::shared::time::tm_from_str;
 
 /// The `LastModified` header field.
 #[deriving(Copy, PartialEq, Clone)]
@@ -40,4 +41,3 @@ impl FromStr for LastModified {
 bench_header!(imf_fixdate, LastModified, { vec![b"Sun, 07 Nov 1994 08:48:37 GMT".to_vec()] });
 bench_header!(rfc_850, LastModified, { vec![b"Sunday, 06-Nov-94 08:49:37 GMT".to_vec()] });
 bench_header!(asctime, LastModified, { vec![b"Sun Nov  6 08:49:37 1994".to_vec()] });
-
diff --git a/src/header/common/location.rs b/src/header/common/location.rs
index ea3b815d..31fdc962 100644
--- a/src/header/common/location.rs
+++ b/src/header/common/location.rs
@@ -1,6 +1,6 @@
 use header::{Header, HeaderFormat};
 use std::fmt::{mod, Show};
-use super::util::from_one_raw_str;
+use header::shared::util::from_one_raw_str;
 
 /// The `Location` header.
 ///
diff --git a/src/header/common/mod.rs b/src/header/common/mod.rs
index bbb4d37e..f6659afa 100644
--- a/src/header/common/mod.rs
+++ b/src/header/common/mod.rs
@@ -7,6 +7,7 @@
 //! is used, such as `ContentType(pub Mime)`.
 
 pub use self::accept::Accept;
+pub use self::accept_encoding::AcceptEncoding;
 pub use self::allow::Allow;
 pub use self::authorization::Authorization;
 pub use self::cache_control::CacheControl;
@@ -76,6 +77,9 @@ macro_rules! deref(
 /// Exposes the Accept header.
 pub mod accept;
 
+/// Exposes the AcceptEncoding header.
+pub mod accept_encoding;
+
 /// Exposes the Allow header.
 pub mod allow;
 
@@ -135,5 +139,3 @@ pub mod user_agent;
 
 /// Exposes the Vary header.
 pub mod vary;
-
-pub mod util;
diff --git a/src/header/common/server.rs b/src/header/common/server.rs
index 64c3ca1d..a7d5d4ed 100644
--- a/src/header/common/server.rs
+++ b/src/header/common/server.rs
@@ -1,6 +1,6 @@
 use header::{Header, HeaderFormat};
 use std::fmt::{mod, Show};
-use super::util::from_one_raw_str;
+use header::shared::util::from_one_raw_str;
 
 /// The `Server` header field.
 ///
@@ -28,4 +28,3 @@ impl HeaderFormat for Server {
 }
 
 bench_header!(bench, Server, { vec![b"Some String".to_vec()] });
-
diff --git a/src/header/common/set_cookie.rs b/src/header/common/set_cookie.rs
index d861624e..4bec8724 100644
--- a/src/header/common/set_cookie.rs
+++ b/src/header/common/set_cookie.rs
@@ -103,16 +103,15 @@ fn test_fmt() {
 
 #[test]
 fn cookie_jar() {
-    let jar = CookieJar::new("secret".as_bytes());
+    let jar = CookieJar::new(b"secret");
     let cookie = Cookie::new("foo".to_string(), "bar".to_string());
     jar.encrypted().add(cookie);
 
     let cookies = SetCookie::from_cookie_jar(&jar);
 
-    let mut new_jar = CookieJar::new("secret".as_bytes());
+    let mut new_jar = CookieJar::new(b"secret");
     cookies.apply_to_cookie_jar(&mut new_jar);
 
     assert_eq!(jar.encrypted().find("foo"), new_jar.encrypted().find("foo"));
     assert_eq!(jar.iter().collect::<Vec<Cookie>>(), new_jar.iter().collect::<Vec<Cookie>>());
 }
-
diff --git a/src/header/common/transfer_encoding.rs b/src/header/common/transfer_encoding.rs
index e0572cf0..47c4ad50 100644
--- a/src/header/common/transfer_encoding.rs
+++ b/src/header/common/transfer_encoding.rs
@@ -1,7 +1,7 @@
 use header::{Header, HeaderFormat};
 use std::fmt;
 use std::str::FromStr;
-use super::util::{from_comma_delimited, fmt_comma_delimited};
+use header::shared::util::{from_comma_delimited, fmt_comma_delimited};
 
 use self::Encoding::{Chunked, Gzip, Deflate, Compress, EncodingExt};
 
diff --git a/src/header/common/upgrade.rs b/src/header/common/upgrade.rs
index 296478b8..10c6009b 100644
--- a/src/header/common/upgrade.rs
+++ b/src/header/common/upgrade.rs
@@ -1,7 +1,7 @@
 use header::{Header, HeaderFormat};
 use std::fmt::{mod, Show};
 use std::str::FromStr;
-use super::util::{from_comma_delimited, fmt_comma_delimited};
+use header::shared::util::{from_comma_delimited, fmt_comma_delimited};
 
 use self::Protocol::{WebSocket, ProtocolExt};
 
diff --git a/src/header/common/user_agent.rs b/src/header/common/user_agent.rs
index f35e7cbd..a51bee3c 100644
--- a/src/header/common/user_agent.rs
+++ b/src/header/common/user_agent.rs
@@ -1,6 +1,6 @@
 use header::{Header, HeaderFormat};
 use std::fmt::{mod, Show};
-use super::util::from_one_raw_str;
+use header::shared::util::from_one_raw_str;
 
 /// The `User-Agent` header field.
 ///
diff --git a/src/header/common/util.rs b/src/header/common/util.rs
deleted file mode 100644
index f5185592..00000000
--- a/src/header/common/util.rs
+++ /dev/null
@@ -1,84 +0,0 @@
-//! Utility functions for Header implementations.
-
-use std::str::{FromStr, from_utf8};
-use std::fmt::{mod, Show};
-use time::{Tm, strptime};
-
-/// Reads a single raw string when parsing a header
-pub fn from_one_raw_str<T: FromStr>(raw: &[Vec<u8>]) -> Option<T> {
-    if raw.len() != 1 {
-        return None;
-    }
-    // we JUST checked that raw.len() == 1, so raw[0] WILL exist.
-    match from_utf8(unsafe { raw[].get_unchecked(0)[] }) {
-        Ok(s) => FromStr::from_str(s),
-        Err(_) => None
-    }
-}
-
-/// Reads a comma-delimited raw header into a Vec.
-#[inline]
-pub fn from_comma_delimited<T: FromStr>(raw: &[Vec<u8>]) -> Option<Vec<T>> {
-    if raw.len() != 1 {
-        return None;
-    }
-    // we JUST checked that raw.len() == 1, so raw[0] WILL exist.
-    from_one_comma_delimited(unsafe { raw.as_slice().get_unchecked(0).as_slice() })
-}
-
-/// Reads a comma-delimited raw string into a Vec.
-pub fn from_one_comma_delimited<T: FromStr>(raw: &[u8]) -> Option<Vec<T>> {
-    match from_utf8(raw) {
-        Ok(s) => {
-            Some(s.as_slice()
-                 .split(',')
-                 .map(|x| x.trim())
-                 .filter_map(FromStr::from_str)
-                 .collect())
-        }
-        Err(_) => None
-    }
-}
-
-/// Format an array into a comma-delimited string.
-pub fn fmt_comma_delimited<T: Show>(fmt: &mut fmt::Formatter, parts: &[T]) -> fmt::Result {
-    let last = parts.len() - 1;
-    for (i, part) in parts.iter().enumerate() {
-        try!(part.fmt(fmt));
-        if i < last {
-            try!(", ".fmt(fmt));
-        }
-    }
-    Ok(())
-}
-
-/// Get a Tm from HTTP date formats.
-//    Prior to 1995, there were three different formats commonly used by
-//   servers to communicate timestamps.  For compatibility with old
-//   implementations, all three are defined here.  The preferred format is
-//   a fixed-length and single-zone subset of the date and time
-//   specification used by the Internet Message Format [RFC5322].
-//
-//     HTTP-date    = IMF-fixdate / obs-date
-//
-//   An example of the preferred format is
-//
-//     Sun, 06 Nov 1994 08:49:37 GMT    ; IMF-fixdate
-//
-//   Examples of the two obsolete formats are
-//
-//     Sunday, 06-Nov-94 08:49:37 GMT   ; obsolete RFC 850 format
-//     Sun Nov  6 08:49:37 1994         ; ANSI C's asctime() format
-//
-//   A recipient that parses a timestamp value in an HTTP header field
-//   MUST accept all three HTTP-date formats.  When a sender generates a
-//   header field that contains one or more timestamps defined as
-//   HTTP-date, the sender MUST generate those timestamps in the
-//   IMF-fixdate format.
-pub fn tm_from_str(s: &str) -> Option<Tm> {
-    strptime(s, "%a, %d %b %Y %T %Z").or_else(|_| {
-        strptime(s, "%A, %d-%b-%y %T %Z")
-    }).or_else(|_| {
-        strptime(s, "%c")
-    }).ok()
-}
diff --git a/src/header/common/vary.rs b/src/header/common/vary.rs
index 40d4fa60..1424c278 100644
--- a/src/header/common/vary.rs
+++ b/src/header/common/vary.rs
@@ -1,6 +1,6 @@
 use header::{Header, HeaderFormat, CaseInsensitive};
 use std::fmt::{mod};
-use super::util::{from_comma_delimited, fmt_comma_delimited, from_one_raw_str};
+use header::shared::util::{from_comma_delimited, fmt_comma_delimited, from_one_raw_str};
 
 /// The `Allow` header.
 /// See also https://tools.ietf.org/html/rfc7231#section-7.1.4
diff --git a/src/header/mod.rs b/src/header/mod.rs
index e79d168a..ba308727 100644
--- a/src/header/mod.rs
+++ b/src/header/mod.rs
@@ -22,10 +22,13 @@ use http::{mod, LineEnding};
 use {HttpResult};
 
 pub use self::common::*;
+pub use self::shared::*;
 
 /// Common Headers
 pub mod common;
 
+pub mod shared;
+
 /// A trait for any object that will represent a header field and value.
 ///
 /// This trait represents the construction and identification of headers,
@@ -193,7 +196,7 @@ impl Headers {
     /// ```
     /// # use hyper::header::Headers;
     /// # let mut headers = Headers::new();
-    /// headers.set_raw("content-length", vec!["5".as_bytes().to_vec()]);
+    /// headers.set_raw("content-length", vec![b"5".to_vec()]);
     /// ```
     pub fn set_raw<K: IntoCow<'static, String, str>>(&mut self, name: K, value: Vec<Vec<u8>>) {
         self.data.insert(CaseInsensitive(name.into_cow()), MuCell::new(Item::raw(value)));
@@ -518,6 +521,7 @@ mod tests {
     use super::CaseInsensitive;
     use super::{Headers, Header, HeaderFormat};
     use super::common::{ContentLength, ContentType, Accept, Host};
+    use super::shared::{QualityItem};
 
     use test::Bencher;
 
@@ -542,13 +546,13 @@ mod tests {
 
     #[test]
     fn test_content_type() {
-        let content_type = Header::parse_header(["text/plain".as_bytes().to_vec()].as_slice());
+        let content_type = Header::parse_header([b"text/plain".to_vec()].as_slice());
         assert_eq!(content_type, Some(ContentType(Mime(Text, Plain, vec![]))));
     }
 
     #[test]
     fn test_accept() {
-        let text_plain = Mime(Text, Plain, vec![]);
+        let text_plain = QualityItem{item: Mime(Text, Plain, vec![]), quality: 1f32};
         let application_vendor = "application/vnd.github.v3.full+json; q=0.5".parse().unwrap();
 
         let accept = Header::parse_header([b"text/plain".to_vec()].as_slice());
diff --git a/src/header/shared/encoding.rs b/src/header/shared/encoding.rs
new file mode 100644
index 00000000..f05d79f1
--- /dev/null
+++ b/src/header/shared/encoding.rs
@@ -0,0 +1,50 @@
+//! Provides an Encoding enum.
+
+use std::fmt;
+use std::str;
+
+pub use self::Encoding::{Chunked, Gzip, Deflate, Compress, Identity, EncodingExt};
+
+/// A value to represent an encoding used in `Transfer-Encoding`
+/// or `Accept-Encoding` header.
+#[deriving(Clone, PartialEq)]
+pub enum Encoding {
+    /// The `chunked` encoding.
+    Chunked,
+    /// The `gzip` encoding.
+    Gzip,
+    /// The `deflate` encoding.
+    Deflate,
+    /// The `compress` encoding.
+    Compress,
+    /// The `identity` encoding.
+    Identity,
+    /// Some other encoding that is less common, can be any String.
+    EncodingExt(String)
+}
+
+impl fmt::Show for Encoding {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Chunked => "chunked",
+            Gzip => "gzip",
+            Deflate => "deflate",
+            Compress => "compress",
+            Identity => "identity",
+            EncodingExt(ref s) => s.as_slice()
+            }.fmt(fmt)
+        }
+    }
+
+impl str::FromStr for Encoding {
+    fn from_str(s: &str) -> Option<Encoding> {
+        match s {
+            "chunked" => Some(Chunked),
+            "deflate" => Some(Deflate),
+            "gzip" => Some(Gzip),
+            "compress" => Some(Compress),
+            "identity" => Some(Identity),
+            _ => Some(EncodingExt(s.to_string()))
+        }
+    }
+}
diff --git a/src/header/shared/mod.rs b/src/header/shared/mod.rs
new file mode 100644
index 00000000..7f4e488a
--- /dev/null
+++ b/src/header/shared/mod.rs
@@ -0,0 +1,26 @@
+//! Various functions, structs and enums useful for many headers.
+
+pub use self::encoding::Encoding;
+pub use self::encoding::Encoding::{
+    Chunked,
+    Gzip,
+    Deflate,
+    Compress,
+    Identity,
+    EncodingExt};
+
+pub use self::quality_item::QualityItem;
+pub use self::quality_item::qitem;
+
+pub use self::time::tm_from_str;
+
+pub use self::util::{
+    from_one_raw_str,
+    from_comma_delimited,
+    from_one_comma_delimited,
+    fmt_comma_delimited};
+
+pub mod encoding;
+pub mod quality_item;
+pub mod time;
+pub mod util;
diff --git a/src/header/shared/quality_item.rs b/src/header/shared/quality_item.rs
new file mode 100644
index 00000000..a58f4737
--- /dev/null
+++ b/src/header/shared/quality_item.rs
@@ -0,0 +1,123 @@
+//! Provides a struct for quality values.
+//!
+//! [RFC7231 Section 5.3.1](https://tools.ietf.org/html/rfc7231#section-5.3.1)
+//! gives more information on quality values in HTTP header fields.
+
+use std::fmt;
+use std::str;
+#[cfg(test)] use super::encoding::*;
+
+/// Represents an item with a quality value as defined in
+/// [RFC7231](https://tools.ietf.org/html/rfc7231#section-5.3.1).
+#[deriving(Clone, PartialEq)]
+pub struct QualityItem<T> {
+    /// The actual contents of the field.
+    pub item: T,
+    /// The quality (client or server preference) for the value.
+    pub quality: f32,
+}
+
+impl<T> QualityItem<T> {
+    /// Creates a new `QualityItem` from an item and a quality.
+    /// The item can be of any type.
+    /// The quality should be a value in the range [0, 1].
+    pub fn new(item: T, quality: f32) -> QualityItem<T> {
+        QualityItem{item: item, quality: quality}
+    }
+}
+
+impl<T: fmt::Show> fmt::Show for QualityItem<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}; q={}", self.item, format!("{:.3}", self.quality).trim_right_matches(['0', '.'].as_slice()))
+    }
+}
+
+impl<T: str::FromStr> str::FromStr for QualityItem<T> {
+    fn from_str(s: &str) -> Option<Self> {
+        // Set defaults used if parsing fails.
+        let mut raw_item = s;
+        let mut quality = 1f32;
+
+        let parts: Vec<&str> = s.rsplitn(1, ';').map(|x| x.trim()).collect();
+        if parts.len() == 2 {
+            let start = parts[0].slice(0, 2);
+            if start == "q=" || start == "Q=" {
+                let q_part = parts[0].slice(2, parts[0].len());
+                if q_part.len() > 5 {
+                    return None;
+                }
+                let x: Option<f32> = q_part.parse();
+                match x {
+                    Some(q_value) => {
+                        if 0f32 <= q_value && q_value <= 1f32 {
+                            quality = q_value;
+                            raw_item = parts[1];
+                            } else {
+                                return None;
+                            }
+                        },
+                    None => return None,
+                }
+            }
+        }
+        let x: Option<T> = raw_item.parse();
+        match x {
+            Some(item) => {
+                Some(QualityItem{ item: item, quality: quality, })
+            },
+            None => return None,
+        }
+    }
+}
+
+/// Convinience function to wrap a value in a `QualityItem`
+/// Sets `q` to the default 1.0
+pub fn qitem<T>(item: T) -> QualityItem<T> {
+    QualityItem::new(item, 1.0)
+}
+
+#[test]
+fn test_quality_item_show1() {
+    let x = qitem(Chunked);
+    assert_eq!(format!("{}", x), "chunked; q=1.000");
+}
+#[test]
+fn test_quality_item_show2() {
+    let x = QualityItem::new(Chunked, 0.001);
+    assert_eq!(format!("{}", x), "chunked; q=0.001");
+}
+#[test]
+fn test_quality_item_show3() {
+    // Custom value
+    let x = QualityItem{
+        item: EncodingExt("identity".to_string()),
+        quality: 0.5f32,
+    };
+    assert_eq!(format!("{}", x), "identity; q=0.500");
+}
+
+#[test]
+fn test_quality_item_from_str1() {
+    let x: Option<QualityItem<Encoding>> = "chunked".parse();
+    assert_eq!(x.unwrap(), QualityItem{ item: Chunked, quality: 1f32, });
+}
+#[test]
+fn test_quality_item_from_str2() {
+    let x: Option<QualityItem<Encoding>> = "chunked; q=1".parse();
+    assert_eq!(x.unwrap(), QualityItem{ item: Chunked, quality: 1f32, });
+}
+#[test]
+fn test_quality_item_from_str3() {
+    let x: Option<QualityItem<Encoding>> = "gzip; q=0.5".parse();
+    assert_eq!(x.unwrap(), QualityItem{ item: Gzip, quality: 0.5f32, });
+}
+#[test]
+fn test_quality_item_from_str4() {
+    let x: Option<QualityItem<Encoding>> = "gzip; q=0.273".parse();
+    assert_eq!(x.unwrap(), QualityItem{ item: Gzip, quality: 0.273f32, });
+}
+#[test]
+fn test_quality_item_from_str5() {
+    let x: Option<QualityItem<Encoding>> = "gzip; q=0.2739999".parse();
+    assert_eq!(x, None);
+}
diff --git a/src/header/shared/time.rs b/src/header/shared/time.rs
new file mode 100644
index 00000000..90e72f1d
--- /dev/null
+++ b/src/header/shared/time.rs
@@ -0,0 +1,34 @@
+//! Provides utility function to parse HTTP header value time.
+
+extern crate time;
+
+/// Get a Tm from HTTP date formats.
+//    Prior to 1995, there were three different formats commonly used by
+//   servers to communicate timestamps.  For compatibility with old
+//   implementations, all three are defined here.  The preferred format is
+//   a fixed-length and single-zone subset of the date and time
+//   specification used by the Internet Message Format [RFC5322].
+//
+//     HTTP-date    = IMF-fixdate / obs-date
+//
+//   An example of the preferred format is
+//
+//     Sun, 06 Nov 1994 08:49:37 GMT    ; IMF-fixdate
+//
+//   Examples of the two obsolete formats are
+//
+//     Sunday, 06-Nov-94 08:49:37 GMT   ; obsolete RFC 850 format
+//     Sun Nov  6 08:49:37 1994         ; ANSI C's asctime() format
+//
+//   A recipient that parses a timestamp value in an HTTP header field
+//   MUST accept all three HTTP-date formats.  When a sender generates a
+//   header field that contains one or more timestamps defined as
+//   HTTP-date, the sender MUST generate those timestamps in the
+//   IMF-fixdate format.
+pub fn tm_from_str(s: &str) -> Option<time::Tm> {
+    time::strptime(s, "%a, %d %b %Y %T %Z").or_else(|_| {
+        time::strptime(s, "%A, %d-%b-%y %T %Z")
+    }).or_else(|_| {
+        time::strptime(s, "%c")
+    }).ok()
+}
diff --git a/src/header/shared/util.rs b/src/header/shared/util.rs
new file mode 100644
index 00000000..86359d66
--- /dev/null
+++ b/src/header/shared/util.rs
@@ -0,0 +1,52 @@
+//! Utility functions for Header implementations.
+
+use std::str;
+use std::fmt;
+
+/// Reads a single raw string when parsing a header
+pub fn from_one_raw_str<T: str::FromStr>(raw: &[Vec<u8>]) -> Option<T> {
+    if raw.len() != 1 {
+        return None;
+    }
+    // we JUST checked that raw.len() == 1, so raw[0] WILL exist.
+    match str::from_utf8(unsafe { raw[].unsafe_get(0)[] }) {
+        Ok(s) => str::FromStr::from_str(s),
+        Err(_) => None
+    }
+}
+
+/// Reads a comma-delimited raw header into a Vec.
+#[inline]
+pub fn from_comma_delimited<T: str::FromStr>(raw: &[Vec<u8>]) -> Option<Vec<T>> {
+    if raw.len() != 1 {
+        return None;
+    }
+    // we JUST checked that raw.len() == 1, so raw[0] WILL exist.
+    from_one_comma_delimited(unsafe { raw.as_slice().unsafe_get(0).as_slice() })
+}
+
+/// Reads a comma-delimited raw string into a Vec.
+pub fn from_one_comma_delimited<T: str::FromStr>(raw: &[u8]) -> Option<Vec<T>> {
+    match str::from_utf8(raw) {
+        Ok(s) => {
+            Some(s.as_slice()
+                 .split(',')
+                 .map(|x| x.trim())
+                 .filter_map(str::FromStr::from_str)
+                 .collect())
+        }
+        Err(_) => None
+    }
+}
+
+/// Format an array into a comma-delimited string.
+pub fn fmt_comma_delimited<T: fmt::Show>(fmt: &mut fmt::Formatter, parts: &[T]) -> fmt::Result {
+    let last = parts.len() - 1;
+    for (i, part) in parts.iter().enumerate() {
+        try!(write!(fmt, "{}", part));
+        if i < last {
+            try!(write!(fmt, ", "));
+        }
+    }
+    Ok(())
+}
diff --git a/src/http.rs b/src/http.rs
index 6f9db324..33f2cda7 100644
--- a/src/http.rs
+++ b/src/http.rs
@@ -789,7 +789,7 @@ mod tests {
         }
 
         read("Host: rust-lang.org\r\n", Ok(Some(("Host".to_string(),
-                                                "rust-lang.org".as_bytes().to_vec()))));
+                                                 b"rust-lang.org".to_vec()))));
     }
 
     #[test]