Files
hyper/src/header/common/if_range.rs
Sean McArthur 316c6fad30 refactor(header): change HttpDate to opaque over SystemTime
This removes the need for someone to use the `time` crate to create a
date compatible with HTTP headers. It now works with the `SystemTime`
type from the standard library.

BREAKING CHANGE: `HttpDate` no longer has public fields. Convert between
  `HttpDate` and `SystemTime` as needed.
2017-04-25 14:30:49 -07:00

91 lines
2.9 KiB
Rust

use std::fmt::{self, Display};
use header::{self, Header, Raw, EntityTag, HttpDate};
/// `If-Range` header, defined in [RFC7233](http://tools.ietf.org/html/rfc7233#section-3.2)
///
/// If a client has a partial copy of a representation and wishes to have
/// an up-to-date copy of the entire representation, it could use the
/// Range header field with a conditional GET (using either or both of
/// If-Unmodified-Since and If-Match.) However, if the precondition
/// fails because the representation has been modified, the client would
/// then have to make a second request to obtain the entire current
/// representation.
///
/// The `If-Range` header field allows a client to \"short-circuit\" the
/// second request. Informally, its meaning is as follows: if the
/// representation is unchanged, send me the part(s) that I am requesting
/// in Range; otherwise, send me the entire representation.
///
/// # ABNF
/// ```plain
/// If-Range = entity-tag / HTTP-date
/// ```
///
/// # Example values
/// * `Sat, 29 Oct 1994 19:43:31 GMT`
/// * `\"xyzzy\"`
///
/// # Examples
/// ```
/// use hyper::header::{Headers, IfRange, EntityTag};
///
/// let mut headers = Headers::new();
/// headers.set(IfRange::EntityTag(EntityTag::new(false, "xyzzy".to_owned())));
/// ```
/// ```
/// use hyper::header::{Headers, IfRange};
/// use std::time::{SystemTime, Duration};
///
/// let mut headers = Headers::new();
/// let fetched = SystemTime::now() - Duration::from_secs(60 * 60 * 24);
/// headers.set(IfRange::Date(fetched.into()));
/// ```
#[derive(Clone, Debug, PartialEq)]
pub enum IfRange {
/// The entity-tag the client has of the resource
EntityTag(EntityTag),
/// The date when the client retrieved the resource
Date(HttpDate),
}
impl Header for IfRange {
fn header_name() -> &'static str {
static NAME: &'static str = "If-Range";
NAME
}
fn parse_header(raw: &Raw) -> ::Result<IfRange> {
let etag: ::Result<EntityTag> = header::parsing::from_one_raw_str(raw);
if let Ok(etag) = etag {
return Ok(IfRange::EntityTag(etag));
}
let date: ::Result<HttpDate> = header::parsing::from_one_raw_str(raw);
if let Ok(date) = date {
return Ok(IfRange::Date(date));
}
Err(::Error::Header)
}
fn fmt_header(&self, f: &mut ::header::Formatter) -> ::std::fmt::Result {
f.fmt_line(self)
}
}
impl Display for IfRange {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
IfRange::EntityTag(ref x) => Display::fmt(x, f),
IfRange::Date(ref x) => Display::fmt(x, f),
}
}
}
#[cfg(test)]
mod test_if_range {
use std::str;
use header::*;
use super::IfRange as HeaderField;
test_header!(test1, vec![b"Sat, 29 Oct 1994 19:43:31 GMT"]);
test_header!(test2, vec![b"\"xyzzy\""]);
test_header!(test3, vec![b"this-is-invalid"], None::<IfRange>);
}