headers/common/pragma.rs
1use HeaderValue;
2
3/// The `Pragma` header defined by HTTP/1.0.
4///
5/// > The "Pragma" header field allows backwards compatibility with
6/// > HTTP/1.0 caches, so that clients can specify a "no-cache" request
7/// > that they will understand (as Cache-Control was not defined until
8/// > HTTP/1.1). When the Cache-Control header field is also present and
9/// > understood in a request, Pragma is ignored.
10/// > In HTTP/1.0, Pragma was defined as an extensible field for
11/// > implementation-specified directives for recipients. This
12/// > specification deprecates such extensions to improve interoperability.
13///
14/// Spec: [https://tools.ietf.org/html/rfc7234#section-5.4][url]
15///
16/// [url]: https://tools.ietf.org/html/rfc7234#section-5.4
17///
18/// # Examples
19///
20/// ```
21/// # extern crate headers;
22/// use headers::Pragma;
23///
24/// let pragma = Pragma::no_cache();
25/// ```
26#[derive(Clone, Debug, PartialEq)]
27pub struct Pragma(HeaderValue);
28
29derive_header! {
30 Pragma(_),
31 name: PRAGMA
32}
33
34impl Pragma {
35 /// Construct the literal `no-cache` Pragma header.
36 pub fn no_cache() -> Pragma {
37 Pragma(HeaderValue::from_static("no-cache"))
38 }
39
40 /// Return whether this pragma is `no-cache`.
41 pub fn is_no_cache(&self) -> bool {
42 self.0 == "no-cache"
43 }
44}
45
46#[cfg(test)]
47mod tests {
48 use super::super::test_decode;
49 use super::Pragma;
50
51 #[test]
52 fn no_cache_is_no_cache() {
53 assert!(Pragma::no_cache().is_no_cache());
54 }
55
56 #[test]
57 fn etc_is_not_no_cache() {
58 let ext = test_decode::<Pragma>(&["dexter"]).unwrap();
59 assert!(!ext.is_no_cache());
60 }
61}