mas_http/
ext.rs

1// Copyright 2024 New Vector Ltd.
2// Copyright 2022-2024 The Matrix.org Foundation C.I.C.
3//
4// SPDX-License-Identifier: AGPL-3.0-only
5// Please see LICENSE in the repository root for full details.
6
7use std::sync::OnceLock;
8
9use http::header::HeaderName;
10use tower_http::cors::CorsLayer;
11
12static PROPAGATOR_HEADERS: OnceLock<Vec<HeaderName>> = OnceLock::new();
13
14/// Notify the CORS layer what opentelemetry propagators are being used. This
15/// helps whitelisting headers in CORS requests.
16///
17/// # Panics
18///
19/// When called twice
20pub fn set_propagator(propagator: &dyn opentelemetry::propagation::TextMapPropagator) {
21    let headers = propagator
22        .fields()
23        .map(|h| HeaderName::try_from(h).unwrap())
24        .collect();
25
26    tracing::debug!(
27        ?headers,
28        "Headers allowed in CORS requests for trace propagators set"
29    );
30    PROPAGATOR_HEADERS
31        .set(headers)
32        .expect(concat!(module_path!(), "::set_propagator was called twice"));
33}
34
35pub trait CorsLayerExt {
36    #[must_use]
37    fn allow_otel_headers<H>(self, headers: H) -> Self
38    where
39        H: IntoIterator<Item = HeaderName>;
40}
41
42impl CorsLayerExt for CorsLayer {
43    fn allow_otel_headers<H>(self, headers: H) -> Self
44    where
45        H: IntoIterator<Item = HeaderName>,
46    {
47        let base = PROPAGATOR_HEADERS.get().cloned().unwrap_or_default();
48        let headers: Vec<_> = headers.into_iter().chain(base).collect();
49        self.allow_headers(headers)
50    }
51}
mas_http/ext.rs

mas_http/
ext.rs
