http_types/cache/
expires.rs

1use crate::headers::{HeaderName, HeaderValue, Headers, ToHeaderValues, EXPIRES};
2use crate::utils::{fmt_http_date, parse_http_date};
3
4use std::fmt::Debug;
5use std::option;
6use std::time::{Duration, SystemTime};
7
8/// HTTP `Expires` header
9///
10/// # Specifications
11///
12/// - [RFC 7234, section 5.3: Expires](https://tools.ietf.org/html/rfc7234#section-5.3)
13///
14/// # Examples
15///
16/// ```
17/// # fn main() -> http_types::Result<()> {
18/// #
19/// use http_types::Response;
20/// use http_types::cache::Expires;
21/// use std::time::{SystemTime, Duration};
22///
23/// let time = SystemTime::now() + Duration::from_secs(5 * 60);
24/// let expires = Expires::new_at(time);
25///
26/// let mut res = Response::new(200);
27/// expires.apply(&mut res);
28///
29/// let expires = Expires::from_headers(res)?.unwrap();
30///
31/// // HTTP dates only have second-precision.
32/// let elapsed = time.duration_since(expires.expiration())?;
33/// assert_eq!(elapsed.as_secs(), 0);
34/// #
35/// # Ok(()) }
36/// ```
37#[derive(Debug, Ord, PartialOrd, Eq, PartialEq)]
38pub struct Expires {
39    instant: SystemTime,
40}
41
42impl Expires {
43    /// Create a new instance of `Expires`.
44    pub fn new(dur: Duration) -> Self {
45        let instant = SystemTime::now() + dur;
46        Self { instant }
47    }
48
49    /// Create a new instance of `Expires` from secs.
50    pub fn new_at(instant: SystemTime) -> Self {
51        Self { instant }
52    }
53
54    /// Get the expiration time.
55    pub fn expiration(&self) -> SystemTime {
56        self.instant
57    }
58
59    /// Create an instance of `Expires` from a `Headers` instance.
60    pub fn from_headers(headers: impl AsRef<Headers>) -> crate::Result<Option<Self>> {
61        let headers = match headers.as_ref().get(EXPIRES) {
62            Some(headers) => headers,
63            None => return Ok(None),
64        };
65
66        // If we successfully parsed the header then there's always at least one
67        // entry. We want the last entry.
68        let header = headers.iter().last().unwrap();
69
70        let instant = parse_http_date(header.as_str())?;
71        Ok(Some(Self { instant }))
72    }
73
74    /// Insert a `HeaderName` + `HeaderValue` pair into a `Headers` instance.
75    pub fn apply(&self, mut headers: impl AsMut<Headers>) {
76        headers.as_mut().insert(EXPIRES, self.value());
77    }
78
79    /// Get the `HeaderName`.
80    pub fn name(&self) -> HeaderName {
81        EXPIRES
82    }
83
84    /// Get the `HeaderValue`.
85    pub fn value(&self) -> HeaderValue {
86        let output = fmt_http_date(self.instant);
87
88        // SAFETY: the internal string is validated to be ASCII.
89        unsafe { HeaderValue::from_bytes_unchecked(output.into()) }
90    }
91}
92
93impl ToHeaderValues for Expires {
94    type Iter = option::IntoIter<HeaderValue>;
95    fn to_header_values(&self) -> crate::Result<Self::Iter> {
96        // A HeaderValue will always convert into itself.
97        Ok(self.value().to_header_values().unwrap())
98    }
99}
100
101#[cfg(test)]
102mod test {
103    use super::*;
104    use crate::headers::Headers;
105
106    #[test]
107    fn smoke() -> crate::Result<()> {
108        let time = SystemTime::now() + Duration::from_secs(5 * 60);
109        let expires = Expires::new_at(time);
110
111        let mut headers = Headers::new();
112        expires.apply(&mut headers);
113
114        let expires = Expires::from_headers(headers)?.unwrap();
115
116        // HTTP dates only have second-precision
117        let elapsed = time.duration_since(expires.expiration())?;
118        assert_eq!(elapsed.as_secs(), 0);
119        Ok(())
120    }
121
122    #[test]
123    fn bad_request_on_parse_error() {
124        let mut headers = Headers::new();
125        headers.insert(EXPIRES, "<nori ate the tag. yum.>");
126        let err = Expires::from_headers(headers).unwrap_err();
127        assert_eq!(err.status(), 400);
128    }
129}
http_types/cache/expires.rs

http_types/cache/
expires.rs
