feat(header): Add support for Retry-After header

This used to be an external crate, https://github.com/jwilm/retry-after

src/header/common/mod.rs

@@ -51,6 +51,7 @@ pub use self::preference_applied::PreferenceApplied;
 pub use self::range::{Range, ByteRangeSpec};
 pub use self::referer::Referer;
 pub use self::referrer_policy::ReferrerPolicy;
+pub use self::retry_after::RetryAfter;
 pub use self::server::Server;
 pub use self::set_cookie::SetCookie;
 pub use self::strict_transport_security::StrictTransportSecurity;
@@ -384,6 +385,7 @@ mod preference_applied;
 mod range;
 mod referer;
 mod referrer_policy;
+mod retry_after;
 mod server;
 mod set_cookie;
 mod strict_transport_security;

src/header/common/retry_after.rs

@@ -0,0 +1,195 @@
+// Copyright (c) 2016 retry-after Developers
+//
+// This file is dual licensed under MIT and Apache 2.0
+//
+// *******************************************************
+//
+// Permission is hereby granted, free of charge, to any
+// person obtaining a copy of this software and associated
+// documentation files (the "Software"), to deal in the
+// Software without restriction, including without
+// limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of
+// the Software, and to permit persons to whom the Software
+// is furnished to do so, subject to the following
+//
+// conditions:
+//
+// The above copyright notice and this permission notice
+// shall be included in all copies or substantial portions
+// of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+// ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+// TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+// PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+// SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+// IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+//
+// *******************************************************
+//
+// Apache License
+// Version 2.0, January 2004
+// http://www.apache.org/licenses/
+
+use header::{Header, Raw};
+use header::shared::HttpDate;
+use time;
+use time::{Duration, Tm};
+use std::fmt;
+
+/// The `Retry-After` header.
+///
+/// The `Retry-After` response-header field can be used with a 503 (Service
+/// Unavailable) response to indicate how long the service is expected to be
+/// unavailable to the requesting client. This field MAY also be used with any
+/// 3xx (Redirection) response to indicate the minimum time the user-agent is
+/// asked wait before issuing the redirected request. The value of this field
+/// can be either an HTTP-date or an integer number of seconds (in decimal)
+/// after the time of the response.
+///
+/// # Examples
+/// ```
+/// # extern crate hyper;
+/// # extern crate time;
+/// # fn main() {
+/// // extern crate time;
+/// use time::{Duration};
+/// use hyper::header::{Headers, RetryAfter};
+///
+/// let mut headers = Headers::new();
+/// headers.set(
+///     RetryAfter::Delay(Duration::seconds(300))
+/// );
+/// # }
+/// ```
+/// ```
+/// # extern crate hyper;
+/// # extern crate time;
+/// # fn main() {
+/// // extern crate time;
+/// use time;
+/// use time::{Duration};
+/// use hyper::header::{Headers, RetryAfter};
+///
+/// let mut headers = Headers::new();
+/// headers.set(
+///     RetryAfter::DateTime(time::now_utc() + Duration::seconds(300))
+/// );
+/// # }
+/// ```
+
+/// Retry-After header, defined in [RFC7231](http://tools.ietf.org/html/rfc7231#section-7.1.3)
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum RetryAfter {
+    /// Retry after this duration has elapsed
+    ///
+    /// This can be coupled with a response time header to produce a DateTime.
+    Delay(Duration),
+
+    /// Retry after the given DateTime
+    DateTime(Tm),
+}
+
+impl Header for RetryAfter {
+    fn header_name() -> &'static str {
+        static NAME: &'static str = "Retry-After";
+        NAME
+    }
+
+    fn parse_header(raw: &Raw) -> ::Result<RetryAfter> {
+        if let Some(ref line) = raw.one() {
+            let utf8_str = match ::std::str::from_utf8(line) {
+                Ok(utf8_str) => utf8_str,
+                Err(_) => return Err(::Error::Header),
+            };
+
+            if let Ok(datetime) = utf8_str.parse::<HttpDate>() {
+                return Ok(RetryAfter::DateTime(datetime.0))
+            }
+
+            if let Ok(seconds) = utf8_str.parse::<i64>() {
+                return Ok(RetryAfter::Delay(Duration::seconds(seconds)));
+            }
+
+            Err(::Error::Header)
+        } else {
+            Err(::Error::Header)
+        }
+    }
+
+    fn fmt_header(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            RetryAfter::Delay(ref duration) => {
+                write!(f, "{}", duration.num_seconds())
+            },
+            RetryAfter::DateTime(ref datetime) => {
+                // According to RFC7231, the sender of an HTTP-date must use the RFC1123 format.
+                // http://tools.ietf.org/html/rfc7231#section-7.1.1.1
+                if let Ok(date_string) = time::strftime("%a, %d %b %Y %T GMT", datetime) {
+                    write!(f, "{}", date_string)
+                } else {
+                    Err(fmt::Error::default())
+                }
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    extern crate httparse;
+
+    use header::{Header, Headers};
+    use header::shared::HttpDate;
+    use time::{Duration};
+
+    use super::RetryAfter;
+
+    #[test]
+    fn header_name_regression() {
+        assert_eq!(RetryAfter::header_name(), "Retry-After");
+    }
+
+    #[test]
+    fn parse_delay() {
+        let retry_after = RetryAfter::parse_header(&vec![b"1234".to_vec()].into()).unwrap();
+
+        assert_eq!(RetryAfter::Delay(Duration::seconds(1234)), retry_after);
+    }
+
+    macro_rules! test_retry_after_datetime {
+        ($name:ident, $bytes:expr) => {
+            #[test]
+            fn $name() {
+                let dt = "Sun, 06 Nov 1994 08:49:37 GMT".parse::<HttpDate>().unwrap();
+                let retry_after = RetryAfter::parse_header(&vec![$bytes.to_vec()].into()).expect("parse_header ok");
+
+                assert_eq!(RetryAfter::DateTime(dt.0), retry_after);
+            }
+        }
+    }
+
+    test_retry_after_datetime!(header_parse_rfc1123, b"Sun, 06 Nov 1994 08:49:37 GMT");
+    test_retry_after_datetime!(header_parse_rfc850, b"Sunday, 06-Nov-94 08:49:37 GMT");
+    test_retry_after_datetime!(header_parse_asctime, b"Sun Nov  6 08:49:37 1994");
+
+    #[test]
+    fn hyper_headers_from_raw_delay() {
+        let headers = Headers::from_raw(&[httparse::Header { name: "Retry-After", value: b"300" }]).unwrap();
+        let retry_after = headers.get::<RetryAfter>().unwrap();
+        assert_eq!(retry_after, &RetryAfter::Delay(Duration::seconds(300)));
+    }
+
+    #[test]
+    fn hyper_headers_from_raw_datetime() {
+        let headers = Headers::from_raw(&[httparse::Header { name: "Retry-After", value: b"Sun, 06 Nov 1994 08:49:37 GMT" }]).unwrap();
+        let retry_after = headers.get::<RetryAfter>().unwrap();
+        let expected = "Sun, 06 Nov 1994 08:49:37 GMT".parse::<HttpDate>().unwrap();
+
+        assert_eq!(retry_after, &RetryAfter::DateTime(expected.0));
+    }
+}