1 use std::fmt::{self, Display};
2 use header::{self, Header, HeaderFormat, EntityTag, HttpDate};
3 
4 /// `If-Range` header, defined in [RFC7233](http://tools.ietf.org/html/rfc7233#section-3.2)
5 ///
6 /// If a client has a partial copy of a representation and wishes to have
7 /// an up-to-date copy of the entire representation, it could use the
8 /// Range header field with a conditional GET (using either or both of
9 /// If-Unmodified-Since and If-Match.)  However, if the precondition
10 /// fails because the representation has been modified, the client would
11 /// then have to make a second request to obtain the entire current
12 /// representation.
13 ///
14 /// The `If-Range` header field allows a client to \"short-circuit\" the
15 /// second request.  Informally, its meaning is as follows: if the
16 /// representation is unchanged, send me the part(s) that I am requesting
17 /// in Range; otherwise, send me the entire representation.
18 ///
19 /// # ABNF
20 /// ```plain
21 /// If-Range = entity-tag / HTTP-date
22 /// ```
23 ///
24 /// # Example values
25 /// * `Sat, 29 Oct 1994 19:43:31 GMT`
26 /// * `\"xyzzy\"`
27 ///
28 /// # Examples
29 /// ```
30 /// use hyper::header::{Headers, IfRange, EntityTag};
31 ///
32 /// let mut headers = Headers::new();
33 /// headers.set(IfRange::EntityTag(EntityTag::new(false, "xyzzy".to_owned())));
34 /// ```
35 /// ```
36 /// # extern crate hyper;
37 /// # extern crate time;
38 /// # fn main() {
39 /// // extern crate time;
40 ///
41 /// use hyper::header::{Headers, IfRange, HttpDate};
42 /// use time::{self, Duration};
43 ///
44 /// let mut headers = Headers::new();
45 /// headers.set(IfRange::Date(HttpDate(time::now() - Duration::days(1))));
46 /// # }
47 /// ```
48 #[derive(Clone, Debug, PartialEq)]
49 pub enum IfRange {
50     /// The entity-tag the client has of the resource
51     EntityTag(EntityTag),
52     /// The date when the client retrieved the resource
53     Date(HttpDate),
54 }
55 
56 impl Header for IfRange {
header_name() -> &'static str57     fn header_name() -> &'static str {
58         "If-Range"
59     }
parse_header(raw: &[Vec<u8>]) -> ::Result<IfRange>60     fn parse_header(raw: &[Vec<u8>]) -> ::Result<IfRange> {
61         let etag: ::Result<EntityTag> = header::parsing::from_one_raw_str(raw);
62         if etag.is_ok() {
63             return Ok(IfRange::EntityTag(etag.unwrap()));
64         }
65         let date: ::Result<HttpDate> = header::parsing::from_one_raw_str(raw);
66         if date.is_ok() {
67             return Ok(IfRange::Date(date.unwrap()));
68         }
69         Err(::Error::Header)
70     }
71 }
72 
73 impl HeaderFormat for IfRange {
fmt_header(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result74     fn fmt_header(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
75         match *self {
76             IfRange::EntityTag(ref x) => Display::fmt(x, f),
77             IfRange::Date(ref x) => Display::fmt(x, f),
78         }
79     }
80 }
81 
82 impl Display for IfRange {
fmt(&self, f: &mut fmt::Formatter) -> fmt::Result83     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
84         self.fmt_header(f)
85     }
86 }
87 
88 #[cfg(test)]
89 mod test_if_range {
90     use std::str;
91     use header::*;
92     use super::IfRange as HeaderField;
93     test_header!(test1, vec![b"Sat, 29 Oct 1994 19:43:31 GMT"]);
94     test_header!(test2, vec![b"\"xyzzy\""]);
95     test_header!(test3, vec![b"this-is-invalid"], None::<IfRange>);
96 }
97