97 lines
3.0 KiB
Rust
97 lines
3.0 KiB
Rust
use std::fmt::{self, Display};
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use header::{self, Header, HeaderFormat, EntityTag, HttpDate};
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/// `If-Range` header, defined in [RFC7233](http://tools.ietf.org/html/rfc7233#section-3.2)
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///
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/// If a client has a partial copy of a representation and wishes to have
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/// an up-to-date copy of the entire representation, it could use the
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/// Range header field with a conditional GET (using either or both of
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/// If-Unmodified-Since and If-Match.) However, if the precondition
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/// fails because the representation has been modified, the client would
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/// then have to make a second request to obtain the entire current
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/// representation.
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///
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/// The `If-Range` header field allows a client to \"short-circuit\" the
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/// second request. Informally, its meaning is as follows: if the
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/// representation is unchanged, send me the part(s) that I am requesting
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/// in Range; otherwise, send me the entire representation.
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///
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/// # ABNF
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/// ```plain
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/// If-Range = entity-tag / HTTP-date
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/// ```
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///
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/// # Example values
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/// * `Sat, 29 Oct 1994 19:43:31 GMT`
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/// * `\"xyzzy\"`
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///
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/// # Examples
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/// ```
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/// use hyper::header::{Headers, IfRange, EntityTag};
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///
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/// let mut headers = Headers::new();
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/// headers.set(IfRange::EntityTag(EntityTag::new(false, "xyzzy".to_owned())));
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/// ```
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/// ```
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/// # extern crate hyper;
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/// # extern crate time;
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/// # fn main() {
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/// // extern crate time;
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///
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/// use hyper::header::{Headers, IfRange, HttpDate};
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/// use time::{self, Duration};
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///
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/// let mut headers = Headers::new();
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/// headers.set(IfRange::Date(HttpDate(time::now() - Duration::days(1))));
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/// # }
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/// ```
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#[derive(Clone, Debug, PartialEq)]
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pub enum IfRange {
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/// The entity-tag the client has of the resource
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EntityTag(EntityTag),
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/// The date when the client retrieved the resource
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Date(HttpDate),
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}
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impl Header for IfRange {
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fn header_name() -> &'static str {
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"If-Range"
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}
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fn parse_header(raw: &[Vec<u8>]) -> ::Result<IfRange> {
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let etag: ::Result<EntityTag> = header::parsing::from_one_raw_str(raw);
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if etag.is_ok() {
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return Ok(IfRange::EntityTag(etag.unwrap()));
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}
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let date: ::Result<HttpDate> = header::parsing::from_one_raw_str(raw);
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if date.is_ok() {
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return Ok(IfRange::Date(date.unwrap()));
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}
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Err(::Error::Header)
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}
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}
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impl HeaderFormat for IfRange {
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fn fmt_header(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
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match *self {
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IfRange::EntityTag(ref x) => Display::fmt(x, f),
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IfRange::Date(ref x) => Display::fmt(x, f),
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}
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}
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}
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impl Display for IfRange {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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self.fmt_header(f)
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}
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}
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#[cfg(test)]
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mod test_if_range {
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use std::str;
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use header::*;
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use super::IfRange as HeaderField;
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test_header!(test1, vec![b"Sat, 29 Oct 1994 19:43:31 GMT"]);
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test_header!(test2, vec![b"\"xyzzy\""]);
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test_header!(test3, vec![b"this-is-invalid"], None::<IfRange>);
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}
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