tower_http/cors/
expose_headers.rs

1use std::{array, fmt};
2
3use http::{
4    header::{self, HeaderName, HeaderValue},
5    request::Parts as RequestParts,
6};
7
8use super::{separated_by_commas, Any, WILDCARD};
9
10/// Holds configuration for how to set the [`Access-Control-Expose-Headers`][mdn] header.
11///
12/// See [`CorsLayer::expose_headers`] for more details.
13///
14/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Expose-Headers
15/// [`CorsLayer::expose_headers`]: super::CorsLayer::expose_headers
16#[derive(Clone, Default)]
17#[must_use]
18pub struct ExposeHeaders(ExposeHeadersInner);
19
20impl ExposeHeaders {
21    /// Expose any / all headers by sending a wildcard (`*`)
22    ///
23    /// See [`CorsLayer::expose_headers`] for more details.
24    ///
25    /// [`CorsLayer::expose_headers`]: super::CorsLayer::expose_headers
26    pub fn any() -> Self {
27        Self(ExposeHeadersInner::Const(Some(WILDCARD)))
28    }
29
30    /// Set multiple exposed header names
31    ///
32    /// See [`CorsLayer::expose_headers`] for more details.
33    ///
34    /// [`CorsLayer::expose_headers`]: super::CorsLayer::expose_headers
35    pub fn list<I>(headers: I) -> Self
36    where
37        I: IntoIterator<Item = HeaderName>,
38    {
39        Self(ExposeHeadersInner::Const(separated_by_commas(
40            headers.into_iter().map(Into::into),
41        )))
42    }
43
44    #[allow(clippy::borrow_interior_mutable_const)]
45    pub(super) fn is_wildcard(&self) -> bool {
46        matches!(&self.0, ExposeHeadersInner::Const(Some(v)) if v == WILDCARD)
47    }
48
49    pub(super) fn to_header(&self, _parts: &RequestParts) -> Option<(HeaderName, HeaderValue)> {
50        let expose_headers = match &self.0 {
51            ExposeHeadersInner::Const(v) => v.clone()?,
52        };
53
54        Some((header::ACCESS_CONTROL_EXPOSE_HEADERS, expose_headers))
55    }
56}
57
58impl fmt::Debug for ExposeHeaders {
59    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
60        match &self.0 {
61            ExposeHeadersInner::Const(inner) => f.debug_tuple("Const").field(inner).finish(),
62        }
63    }
64}
65
66impl From<Any> for ExposeHeaders {
67    fn from(_: Any) -> Self {
68        Self::any()
69    }
70}
71
72impl<const N: usize> From<[HeaderName; N]> for ExposeHeaders {
73    fn from(arr: [HeaderName; N]) -> Self {
74        #[allow(deprecated)] // Can be changed when MSRV >= 1.53
75        Self::list(array::IntoIter::new(arr))
76    }
77}
78
79impl From<Vec<HeaderName>> for ExposeHeaders {
80    fn from(vec: Vec<HeaderName>) -> Self {
81        Self::list(vec)
82    }
83}
84
85#[derive(Clone)]
86enum ExposeHeadersInner {
87    Const(Option<HeaderValue>),
88}
89
90impl Default for ExposeHeadersInner {
91    fn default() -> Self {
92        ExposeHeadersInner::Const(None)
93    }
94}
tower_http/cors/expose_headers.rs

tower_http/cors/
expose_headers.rs
