rama_http_headers/common/
if_unmodified_since.rs

1use rama_core::telemetry::tracing;
2use rama_http_types::HeaderValue;
3
4use crate::util::HttpDate;
5use std::time::SystemTime;
6
7/// `If-Unmodified-Since` header, defined in
8/// [RFC7232](https://datatracker.ietf.org/doc/html/rfc7232#section-3.4)
9///
10/// The `If-Unmodified-Since` header field makes the request method
11/// conditional on the selected representation's last modification date
12/// being earlier than or equal to the date provided in the field-value.
13/// This field accomplishes the same purpose as If-Match for cases where
14/// the user agent does not have an entity-tag for the representation.
15///
16/// # ABNF
17///
18/// ```text
19/// If-Unmodified-Since = HTTP-date
20/// ```
21///
22/// # Example values
23///
24/// * `Sat, 29 Oct 1994 19:43:31 GMT`
25///
26/// # Example
27///
28/// ```
29/// use rama_http_headers::IfUnmodifiedSince;
30/// use std::time::Duration;
31/// use rama_utils::time::now_system_time;
32///
33/// let time = now_system_time() - Duration::from_hours(24);
34/// let if_unmod = IfUnmodifiedSince::from(time);
35/// ```
36#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
37pub struct IfUnmodifiedSince(HttpDate);
38
39impl crate::TypedHeader for IfUnmodifiedSince {
40    fn name() -> &'static ::rama_http_types::header::HeaderName {
41        &::rama_http_types::header::IF_UNMODIFIED_SINCE
42    }
43}
44
45impl crate::HeaderDecode for IfUnmodifiedSince {
46    fn decode<'i, I>(values: &mut I) -> Result<Self, crate::Error>
47    where
48        I: Iterator<Item = &'i ::rama_http_types::header::HeaderValue>,
49    {
50        crate::util::TryFromValues::try_from_values(values).map(IfUnmodifiedSince)
51    }
52}
53
54impl crate::HeaderEncode for IfUnmodifiedSince {
55    fn encode<E: Extend<HeaderValue>>(&self, values: &mut E) {
56        match HeaderValue::try_from(&self.0) {
57            Ok(value) => values.extend(::std::iter::once(value)),
58            Err(err) => {
59                tracing::debug!("failed to encode if-unmodified-since value as header: {err}");
60            }
61        }
62    }
63}
64
65impl IfUnmodifiedSince {
66    /// Check if the supplied time passes the precondtion.
67    #[must_use]
68    pub fn precondition_passes(&self, last_modified: SystemTime) -> bool {
69        self.0 >= last_modified.into()
70    }
71}
72
73impl From<SystemTime> for IfUnmodifiedSince {
74    fn from(time: SystemTime) -> Self {
75        Self(time.into())
76    }
77}
78
79impl From<IfUnmodifiedSince> for SystemTime {
80    fn from(date: IfUnmodifiedSince) -> Self {
81        date.0.into()
82    }
83}
84
85#[cfg(test)]
86mod tests {
87    use rama_utils::time::now_system_time;
88
89    use super::*;
90    use std::time::Duration;
91
92    #[test]
93    fn precondition_passes() {
94        let newer = now_system_time();
95        let exact = newer - Duration::from_secs(2);
96        let older = newer - Duration::from_secs(4);
97
98        let if_unmod = IfUnmodifiedSince::from(exact);
99        assert!(!if_unmod.precondition_passes(newer));
100        assert!(if_unmod.precondition_passes(exact));
101        assert!(if_unmod.precondition_passes(older));
102    }
103}
rama_http_headers/common/if_unmodified_since.rs

rama_http_headers/common/
if_unmodified_since.rs
