rama_http_headers/common/
expect.rs

1use std::fmt;
2
3use rama_http_types::{HeaderName, HeaderValue};
4
5use crate::util::IterExt;
6use crate::{Error, HeaderDecode, HeaderEncode, TypedHeader};
7
8/// The `Expect` header.
9///
10/// > The "Expect" header field in a request indicates a certain set of
11/// > behaviors (expectations) that need to be supported by the server in
12/// > order to properly handle this request.  The only such expectation
13/// > defined by this specification is 100-continue.
14/// >
15/// >    Expect  = "100-continue"
16///
17/// # Example
18///
19/// ```
20/// use rama_http_headers::Expect;
21///
22/// let expect = Expect::CONTINUE;
23/// ```
24#[derive(Clone, PartialEq)]
25pub struct Expect(());
26
27impl Expect {
28    /// "100-continue"
29    pub const CONTINUE: Self = Self(());
30}
31
32impl TypedHeader for Expect {
33    fn name() -> &'static HeaderName {
34        &::rama_http_types::header::EXPECT
35    }
36}
37
38impl HeaderDecode for Expect {
39    fn decode<'i, I: Iterator<Item = &'i HeaderValue>>(values: &mut I) -> Result<Self, Error> {
40        values
41            .just_one()
42            .and_then(|value| {
43                if value == "100-continue" {
44                    Some(Self::CONTINUE)
45                } else {
46                    None
47                }
48            })
49            .ok_or_else(Error::invalid)
50    }
51}
52
53impl HeaderEncode for Expect {
54    fn encode<E: Extend<HeaderValue>>(&self, values: &mut E) {
55        values.extend(::std::iter::once(HeaderValue::from_static("100-continue")));
56    }
57}
58
59impl fmt::Debug for Expect {
60    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
61        f.debug_tuple("Expect").field(&"100-continue").finish()
62    }
63}
64
65#[cfg(test)]
66mod tests {
67    use super::super::test_decode;
68    use super::Expect;
69
70    #[test]
71    fn expect_continue() {
72        assert_eq!(
73            test_decode::<Expect>(&["100-continue"]),
74            Some(Expect::CONTINUE),
75        );
76    }
77
78    #[test]
79    fn expectation_failed() {
80        assert_eq!(test_decode::<Expect>(&["sandwich"]), None,);
81    }
82
83    #[test]
84    fn too_many_values() {
85        assert_eq!(
86            test_decode::<Expect>(&["100-continue", "100-continue"]),
87            None,
88        );
89    }
90}
rama_http_headers/common/expect.rs

rama_http_headers/common/
expect.rs
