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actix-extras/actix-cors/src/builder.rs
2024-06-09 23:08:20 +01:00

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use std::{collections::HashSet, rc::Rc};
use actix_utils::future::{self, Ready};
use actix_web::{
body::{EitherBody, MessageBody},
dev::{RequestHead, Service, ServiceRequest, ServiceResponse, Transform},
error::HttpError,
http::{
header::{HeaderName, HeaderValue},
Method, Uri,
},
Either, Error, Result,
};
use log::error;
use once_cell::sync::Lazy;
use smallvec::smallvec;
use crate::{AllOrSome, CorsError, CorsMiddleware, Inner, OriginFn};
/// Convenience for getting mut refs to inner. Cleaner than `Rc::get_mut`.
/// Additionally, always causes first error (if any) to be reported during initialization.
fn cors<'a>(
inner: &'a mut Rc<Inner>,
err: &Option<Either<HttpError, CorsError>>,
) -> Option<&'a mut Inner> {
if err.is_some() {
return None;
}
Rc::get_mut(inner)
}
static ALL_METHODS_SET: Lazy<HashSet<Method>> = Lazy::new(|| {
HashSet::from_iter(vec![
Method::GET,
Method::POST,
Method::PUT,
Method::DELETE,
Method::HEAD,
Method::OPTIONS,
Method::CONNECT,
Method::PATCH,
Method::TRACE,
])
});
/// Builder for CORS middleware.
///
/// To construct a CORS middleware, call [`Cors::default()`] to create a blank, restrictive builder.
/// Then use any of the builder methods to customize CORS behavior.
///
/// The alternative [`Cors::permissive()`] constructor is available for local development, allowing
/// all origins and headers, etc. **The permissive constructor should not be used in production.**
///
/// # Behavior
///
/// In all cases, behavior for this crate follows the [Fetch Standard CORS protocol]. See that
/// document for information on exact semantics for configuration options and combinations.
///
/// # Errors
///
/// Errors surface in the middleware initialization phase. This means that, if you have logs enabled
/// in Actix Web (using `env_logger` or other crate that exposes logs from the `log` crate), error
/// messages will outline what is wrong with the CORS configuration in the server logs and the
/// server will fail to start up or serve requests.
///
/// # Example
///
/// ```
/// use actix_cors::Cors;
/// use actix_web::http::header;
///
/// let cors = Cors::default()
/// .allowed_origin("https://www.rust-lang.org")
/// .allowed_methods(vec!["GET", "POST"])
/// .allowed_headers(vec![header::AUTHORIZATION, header::ACCEPT])
/// .allowed_header(header::CONTENT_TYPE)
/// .max_age(3600);
///
/// // `cors` can now be used in `App::wrap`.
/// ```
///
/// [Fetch Standard CORS protocol]: https://fetch.spec.whatwg.org/#http-cors-protocol
#[derive(Debug)]
#[must_use]
pub struct Cors {
inner: Rc<Inner>,
error: Option<Either<HttpError, CorsError>>,
}
impl Cors {
/// Constructs a very permissive set of defaults for quick development. (Not recommended for
/// production use.)
///
/// *All* origins, methods, request headers and exposed headers allowed. Credentials supported.
/// Max age 1 hour. Does not send wildcard.
pub fn permissive() -> Self {
let inner = Inner {
allowed_origins: AllOrSome::All,
allowed_origins_fns: smallvec![],
allowed_methods: ALL_METHODS_SET.clone(),
allowed_methods_baked: None,
allowed_headers: AllOrSome::All,
allowed_headers_baked: None,
expose_headers: AllOrSome::All,
expose_headers_baked: None,
max_age: Some(3600),
preflight: true,
send_wildcard: false,
supports_credentials: true,
#[cfg(feature = "draft-private-network-access")]
allow_private_network_access: false,
vary_header: true,
block_on_origin_mismatch: false,
};
Cors {
inner: Rc::new(inner),
error: None,
}
}
/// Resets allowed origin list to a state where any origin is accepted.
///
/// See [`Cors::allowed_origin`] for more info on allowed origins.
pub fn allow_any_origin(mut self) -> Cors {
if let Some(cors) = cors(&mut self.inner, &self.error) {
cors.allowed_origins = AllOrSome::All;
}
self
}
/// Adds an origin that is allowed to make requests.
///
/// This method allows specifying a finite set of origins to verify the value of the `Origin`
/// request header. These are `origin-or-null` types in the [Fetch Standard].
///
/// By default, no origins are accepted.
///
/// When this list is set, the client's `Origin` request header will be checked in a
/// case-sensitive manner.
///
/// When all origins are allowed and `send_wildcard` is set, `*` will be sent in the
/// `Access-Control-Allow-Origin` response header. If `send_wildcard` is not set, the client's
/// `Origin` request header will be echoed back in the `Access-Control-Allow-Origin`
/// response header.
///
/// If the origin of the request doesn't match any allowed origins and at least one
/// `allowed_origin_fn` function is set, these functions will be used to determinate
/// allowed origins.
///
/// # Initialization Errors
/// - If supplied origin is not valid uri
/// - If supplied origin is a wildcard (`*`). [`Cors::send_wildcard`] should be used instead.
///
/// [Fetch Standard]: https://fetch.spec.whatwg.org/#origin-header
pub fn allowed_origin(mut self, origin: &str) -> Cors {
if let Some(cors) = cors(&mut self.inner, &self.error) {
match TryInto::<Uri>::try_into(origin) {
Ok(_) if origin == "*" => {
error!("Wildcard in `allowed_origin` is not allowed. Use `send_wildcard`.");
self.error = Some(Either::Right(CorsError::WildcardOrigin));
}
Ok(_) => {
if cors.allowed_origins.is_all() {
cors.allowed_origins = AllOrSome::Some(HashSet::with_capacity(8));
}
if let Some(origins) = cors.allowed_origins.as_mut() {
// any uri is a valid header value
let hv = origin.try_into().unwrap();
origins.insert(hv);
}
}
Err(err) => {
self.error = Some(Either::Left(err.into()));
}
}
}
self
}
/// Determinates allowed origins by processing requests which didn't match any origins specified
/// in the `allowed_origin`.
///
/// The function will receive two parameters, the Origin header value, and the `RequestHead` of
/// each request, which can be used to determine whether to allow the request or not.
///
/// If the function returns `true`, the client's `Origin` request header will be echoed back
/// into the `Access-Control-Allow-Origin` response header.
pub fn allowed_origin_fn<F>(mut self, f: F) -> Cors
where
F: (Fn(&HeaderValue, &RequestHead) -> bool) + 'static,
{
if let Some(cors) = cors(&mut self.inner, &self.error) {
cors.allowed_origins_fns.push(OriginFn {
boxed_fn: Rc::new(f),
});
}
self
}
/// Resets allowed methods list to all methods.
///
/// See [`Cors::allowed_methods`] for more info on allowed methods.
pub fn allow_any_method(mut self) -> Cors {
if let Some(cors) = cors(&mut self.inner, &self.error) {
ALL_METHODS_SET.clone_into(&mut cors.allowed_methods);
}
self
}
/// Sets a list of methods which allowed origins can perform.
///
/// These will be sent in the `Access-Control-Allow-Methods` response header.
///
/// This defaults to an empty set.
pub fn allowed_methods<U, M>(mut self, methods: U) -> Cors
where
U: IntoIterator<Item = M>,
M: TryInto<Method>,
<M as TryInto<Method>>::Error: Into<HttpError>,
{
if let Some(cors) = cors(&mut self.inner, &self.error) {
for m in methods {
match m.try_into() {
Ok(method) => {
cors.allowed_methods.insert(method);
}
Err(err) => {
self.error = Some(Either::Left(err.into()));
break;
}
}
}
}
self
}
/// Resets allowed request header list to a state where any header is accepted.
///
/// See [`Cors::allowed_headers`] for more info on allowed request headers.
pub fn allow_any_header(mut self) -> Cors {
if let Some(cors) = cors(&mut self.inner, &self.error) {
cors.allowed_headers = AllOrSome::All;
}
self
}
/// Add an allowed request header.
///
/// See [`Cors::allowed_headers`] for more info on allowed request headers.
pub fn allowed_header<H>(mut self, header: H) -> Cors
where
H: TryInto<HeaderName>,
<H as TryInto<HeaderName>>::Error: Into<HttpError>,
{
if let Some(cors) = cors(&mut self.inner, &self.error) {
match header.try_into() {
Ok(method) => {
if cors.allowed_headers.is_all() {
cors.allowed_headers = AllOrSome::Some(HashSet::with_capacity(8));
}
if let AllOrSome::Some(ref mut headers) = cors.allowed_headers {
headers.insert(method);
}
}
Err(err) => self.error = Some(Either::Left(err.into())),
}
}
self
}
/// Sets a list of request header field names which can be used when this resource is accessed
/// by allowed origins.
///
/// If `All` is set, whatever is requested by the client in `Access-Control-Request-Headers`
/// will be echoed back in the `Access-Control-Allow-Headers` header.
///
/// This defaults to an empty set.
pub fn allowed_headers<U, H>(mut self, headers: U) -> Cors
where
U: IntoIterator<Item = H>,
H: TryInto<HeaderName>,
<H as TryInto<HeaderName>>::Error: Into<HttpError>,
{
if let Some(cors) = cors(&mut self.inner, &self.error) {
for h in headers {
match h.try_into() {
Ok(method) => {
if cors.allowed_headers.is_all() {
cors.allowed_headers = AllOrSome::Some(HashSet::with_capacity(8));
}
if let AllOrSome::Some(ref mut headers) = cors.allowed_headers {
headers.insert(method);
}
}
Err(err) => {
self.error = Some(Either::Left(err.into()));
break;
}
}
}
}
self
}
/// Resets exposed response header list to a state where all headers are exposed.
///
/// See [`Cors::expose_headers`] for more info on exposed response headers.
pub fn expose_any_header(mut self) -> Cors {
if let Some(cors) = cors(&mut self.inner, &self.error) {
cors.expose_headers = AllOrSome::All;
}
self
}
/// Sets a list of headers which are safe to expose to the API of a CORS API specification.
///
/// This corresponds to the `Access-Control-Expose-Headers` response header.
///
/// This defaults to an empty set.
pub fn expose_headers<U, H>(mut self, headers: U) -> Cors
where
U: IntoIterator<Item = H>,
H: TryInto<HeaderName>,
<H as TryInto<HeaderName>>::Error: Into<HttpError>,
{
for h in headers {
match h.try_into() {
Ok(header) => {
if let Some(cors) = cors(&mut self.inner, &self.error) {
if cors.expose_headers.is_all() {
cors.expose_headers = AllOrSome::Some(HashSet::with_capacity(8));
}
if let AllOrSome::Some(ref mut headers) = cors.expose_headers {
headers.insert(header);
}
}
}
Err(err) => {
self.error = Some(Either::Left(err.into()));
break;
}
}
}
self
}
/// Sets a maximum time (in seconds) for which this CORS request may be cached.
///
/// This value is set as the `Access-Control-Max-Age` header.
///
/// Pass a number (of seconds) or use None to disable sending max age header.
pub fn max_age(mut self, max_age: impl Into<Option<usize>>) -> Cors {
if let Some(cors) = cors(&mut self.inner, &self.error) {
cors.max_age = max_age.into();
}
self
}
/// Configures use of wildcard (`*`) origin in responses when appropriate.
///
/// If send wildcard is set and the `allowed_origins` parameter is `All`, a wildcard
/// `Access-Control-Allow-Origin` response header is sent, rather than the requests
/// `Origin` header.
///
/// This option **CANNOT** be used in conjunction with a [credential
/// supported](Self::supports_credentials()) configuration. Doing so will result in an error
/// during server startup.
///
/// Defaults to disabled.
pub fn send_wildcard(mut self) -> Cors {
if let Some(cors) = cors(&mut self.inner, &self.error) {
cors.send_wildcard = true;
}
self
}
/// Allows users to make authenticated requests.
///
/// If true, injects the `Access-Control-Allow-Credentials` header in responses. This allows
/// cookies and credentials to be submitted across domains.
///
/// This option **CANNOT** be used in conjunction with option cannot be used in conjunction
/// with [wildcard origins](Self::send_wildcard()) configured. Doing so will result in an error
/// during server startup.
///
/// Defaults to disabled.
pub fn supports_credentials(mut self) -> Cors {
if let Some(cors) = cors(&mut self.inner, &self.error) {
cors.supports_credentials = true;
}
self
}
/// Allow private network access.
///
/// If true, injects the `Access-Control-Allow-Private-Network: true` header in responses if the
/// request contained the `Access-Control-Request-Private-Network: true` header.
///
/// For more information on this behavior, see the draft [Private Network Access] spec.
///
/// Defaults to `false`.
///
/// [Private Network Access]: https://wicg.github.io/private-network-access
#[cfg(feature = "draft-private-network-access")]
pub fn allow_private_network_access(mut self) -> Cors {
if let Some(cors) = cors(&mut self.inner, &self.error) {
cors.allow_private_network_access = true;
}
self
}
/// Disables `Vary` header support.
///
/// When enabled the header `Vary: Origin` will be returned as per the Fetch Standard
/// implementation guidelines.
///
/// Setting this header when the `Access-Control-Allow-Origin` is dynamically generated
/// (eg. when there is more than one allowed origin, and an Origin other than '*' is returned)
/// informs CDNs and other caches that the CORS headers are dynamic, and cannot be cached.
///
/// By default, `Vary` header support is enabled.
pub fn disable_vary_header(mut self) -> Cors {
if let Some(cors) = cors(&mut self.inner, &self.error) {
cors.vary_header = false;
}
self
}
/// Disables preflight request handling.
///
/// When enabled CORS middleware automatically handles `OPTIONS` requests. This is useful for
/// application level middleware.
///
/// By default, preflight support is enabled.
pub fn disable_preflight(mut self) -> Cors {
if let Some(cors) = cors(&mut self.inner, &self.error) {
cors.preflight = false;
}
self
}
/// Configures whether requests should be pre-emptively blocked on mismatched origin.
///
/// If `true`, a 400 Bad Request is returned immediately when a request fails origin validation.
///
/// If `false`, the request will be processed as normal but relevant CORS headers will not be
/// appended to the response. In this case, the browser is trusted to validate CORS headers and
/// and block requests based on pre-flight requests. Use this setting to allow cURL and other
/// non-browser HTTP clients to function as normal, no matter what `Origin` the request has.
///
/// Defaults to false.
pub fn block_on_origin_mismatch(mut self, block: bool) -> Cors {
if let Some(cors) = cors(&mut self.inner, &self.error) {
cors.block_on_origin_mismatch = block;
}
self
}
}
impl Default for Cors {
/// A restrictive (security paranoid) set of defaults.
///
/// *No* allowed origins, methods, request headers or exposed headers. Credentials
/// not supported. No max age (will use browser's default).
fn default() -> Cors {
let inner = Inner {
allowed_origins: AllOrSome::Some(HashSet::with_capacity(8)),
allowed_origins_fns: smallvec![],
allowed_methods: HashSet::with_capacity(8),
allowed_methods_baked: None,
allowed_headers: AllOrSome::Some(HashSet::with_capacity(8)),
allowed_headers_baked: None,
expose_headers: AllOrSome::Some(HashSet::with_capacity(8)),
expose_headers_baked: None,
max_age: None,
preflight: true,
send_wildcard: false,
supports_credentials: false,
#[cfg(feature = "draft-private-network-access")]
allow_private_network_access: false,
vary_header: true,
block_on_origin_mismatch: false,
};
Cors {
inner: Rc::new(inner),
error: None,
}
}
}
impl<S, B> Transform<S, ServiceRequest> for Cors
where
S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
S::Future: 'static,
B: MessageBody + 'static,
{
type Response = ServiceResponse<EitherBody<B>>;
type Error = Error;
type InitError = ();
type Transform = CorsMiddleware<S>;
type Future = Ready<Result<Self::Transform, Self::InitError>>;
fn new_transform(&self, service: S) -> Self::Future {
if let Some(ref err) = self.error {
match err {
Either::Left(err) => error!("{}", err),
Either::Right(err) => error!("{}", err),
}
return future::err(());
}
let mut inner = Rc::clone(&self.inner);
if inner.supports_credentials && inner.send_wildcard && inner.allowed_origins.is_all() {
error!(
"Illegal combination of CORS options: credentials can not be supported when all \
origins are allowed and `send_wildcard` is enabled."
);
return future::err(());
}
// bake allowed headers value if Some and not empty
match inner.allowed_headers.as_ref() {
Some(header_set) if !header_set.is_empty() => {
let allowed_headers_str = intersperse_header_values(header_set);
Rc::make_mut(&mut inner).allowed_headers_baked = Some(allowed_headers_str);
}
_ => {}
}
// bake allowed methods value if not empty
if !inner.allowed_methods.is_empty() {
let allowed_methods_str = intersperse_header_values(&inner.allowed_methods);
Rc::make_mut(&mut inner).allowed_methods_baked = Some(allowed_methods_str);
}
// bake exposed headers value if Some and not empty
match inner.expose_headers.as_ref() {
Some(header_set) if !header_set.is_empty() => {
let expose_headers_str = intersperse_header_values(header_set);
Rc::make_mut(&mut inner).expose_headers_baked = Some(expose_headers_str);
}
_ => {}
}
future::ok(CorsMiddleware { service, inner })
}
}
/// Only call when values are guaranteed to be valid header values and set is not empty.
pub(crate) fn intersperse_header_values<T>(val_set: &HashSet<T>) -> HeaderValue
where
T: AsRef<str>,
{
debug_assert!(
!val_set.is_empty(),
"only call `intersperse_header_values` when set is not empty"
);
val_set
.iter()
.fold(String::with_capacity(64), |mut acc, val| {
acc.push_str(", ");
acc.push_str(val.as_ref());
acc
})
// set is not empty so string will always have leading ", " to trim
[2..]
.try_into()
// all method names are valid header values
.unwrap()
}
#[cfg(test)]
mod test {
use std::convert::Infallible;
use actix_web::{
body,
dev::fn_service,
http::StatusCode,
test::{self, TestRequest},
HttpResponse,
};
use super::*;
#[test]
fn illegal_allow_credentials() {
// using the permissive defaults (all origins allowed) and adding send_wildcard
// and supports_credentials should error on construction
assert!(Cors::permissive()
.supports_credentials()
.send_wildcard()
.new_transform(test::ok_service())
.into_inner()
.is_err());
}
#[actix_web::test]
async fn restrictive_defaults() {
let cors = Cors::default()
.new_transform(test::ok_service())
.await
.unwrap();
let req = TestRequest::default()
.insert_header(("Origin", "https://www.example.com"))
.to_srv_request();
let res = test::call_service(&cors, req).await;
assert_eq!(res.status(), StatusCode::OK);
assert!(!res.headers().contains_key("Access-Control-Allow-Origin"));
}
#[actix_web::test]
async fn allowed_header_try_from() {
let _cors = Cors::default().allowed_header("Content-Type");
}
#[actix_web::test]
async fn allowed_header_try_into() {
struct ContentType;
impl TryInto<HeaderName> for ContentType {
type Error = Infallible;
fn try_into(self) -> Result<HeaderName, Self::Error> {
Ok(HeaderName::from_static("content-type"))
}
}
let _cors = Cors::default().allowed_header(ContentType);
}
#[actix_web::test]
async fn middleware_generic_over_body_type() {
let srv = fn_service(|req: ServiceRequest| async move {
Ok(req.into_response(HttpResponse::with_body(StatusCode::OK, body::None::new())))
});
Cors::default().new_transform(srv).await.unwrap();
}
}