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use std::{collections::HashSet, sync::Arc};
use crate::{
async_trait,
header::{
HeaderMap, HeaderName, HeaderValue, ACCESS_CONTROL_ALLOW_CREDENTIALS,
ACCESS_CONTROL_ALLOW_HEADERS, ACCESS_CONTROL_ALLOW_ORIGIN, ACCESS_CONTROL_REQUEST_HEADERS,
ACCESS_CONTROL_REQUEST_METHOD, ORIGIN, VARY,
},
headers::{
AccessControlAllowHeaders, AccessControlAllowMethods, AccessControlExposeHeaders,
HeaderMapExt,
},
Handler, IntoResponse, Method, Request, RequestExt, Response, Result, StatusCode, Transform,
};
pub struct Config {
max_age: usize,
credentials: bool,
allow_methods: HashSet<Method>,
allow_headers: HashSet<HeaderName>,
allow_origins: HashSet<HeaderValue>,
expose_headers: HashSet<HeaderName>,
origin_verify: Option<Arc<dyn Fn(&HeaderValue) -> bool + Send + Sync>>,
}
impl Default for Config {
fn default() -> Self {
Self {
max_age: 86400,
credentials: false,
allow_methods: HashSet::from([
Method::GET,
Method::POST,
Method::HEAD,
Method::PUT,
Method::DELETE,
Method::PATCH,
]),
allow_origins: HashSet::from([HeaderValue::from_static("*")]),
allow_headers: HashSet::new(),
expose_headers: HashSet::new(),
origin_verify: None,
}
}
}
impl Clone for Config {
fn clone(&self) -> Self {
Self {
max_age: self.max_age,
credentials: self.credentials,
allow_methods: self.allow_methods.clone(),
allow_headers: self.allow_headers.clone(),
allow_origins: self.allow_origins.clone(),
expose_headers: self.expose_headers.clone(),
origin_verify: self.origin_verify.clone(),
}
}
}
impl<H> Transform<H> for Config {
type Output = CorsMiddleware<H>;
fn transform(&self, h: H) -> Self::Output {
CorsMiddleware {
h,
acam: self.allow_methods.clone().into_iter().collect(),
acah: self.allow_headers.clone().into_iter().collect(),
aceh: self.expose_headers.clone().into_iter().collect(),
config: self.clone(),
}
}
}
#[derive(Clone)]
pub struct CorsMiddleware<H> {
h: H,
config: Config,
acam: AccessControlAllowMethods,
acah: AccessControlAllowHeaders,
aceh: AccessControlExposeHeaders,
}
#[async_trait]
impl<H, O> Handler<Request> for CorsMiddleware<H>
where
O: IntoResponse,
H: Handler<Request, Output = Result<O>> + Clone,
{
type Output = Result<Response>;
async fn call(&self, req: Request) -> Self::Output {
let origin = match req.header(ORIGIN).filter(is_not_empty) {
Some(origin) => origin,
None => return self.h.call(req).await.map(IntoResponse::into_response),
};
if !self.config.allow_origins.contains(&origin)
|| !self
.config
.origin_verify
.as_ref()
.map(|f| (f)(&origin))
.unwrap_or(true)
{
return Err(StatusCode::FORBIDDEN.into_error());
}
let mut headers = HeaderMap::new();
let mut res = if req.method() == Method::OPTIONS {
if req
.header(ACCESS_CONTROL_REQUEST_METHOD)
.map(|method| {
self.config.allow_methods.is_empty()
|| self.config.allow_methods.contains(&method)
})
.unwrap_or(false)
{
headers.typed_insert(self.acam.clone());
} else {
return Err((StatusCode::FORBIDDEN, "Invalid Preflight Request").into_error());
}
let (allow_headers, request_headers) = req
.header(ACCESS_CONTROL_REQUEST_HEADERS)
.map(|hs: HeaderValue| {
(
hs.to_str()
.map(|hs| {
hs.split(',')
.filter_map(|h| HeaderName::from_bytes(h.as_bytes()).ok())
.any(|header| self.config.allow_headers.contains(&header))
})
.unwrap_or(false),
Some(hs),
)
})
.unwrap_or((true, None));
if !allow_headers {
return Err((StatusCode::FORBIDDEN, "Invalid Preflight Request").into_error());
}
if self.config.allow_headers.is_empty() {
headers.insert(
ACCESS_CONTROL_ALLOW_HEADERS,
request_headers.unwrap_or(HeaderValue::from_static("*")),
);
} else {
headers.typed_insert(self.acah.clone());
}
StatusCode::NO_CONTENT.into_response()
} else {
if !self.config.expose_headers.is_empty() {
headers.typed_insert(self.aceh.clone());
}
self.h
.call(req)
.await
.map_or_else(IntoResponse::into_response, IntoResponse::into_response)
};
headers.insert(VARY, ORIGIN.into());
headers.insert(ACCESS_CONTROL_ALLOW_ORIGIN, origin);
if self.config.credentials {
headers.insert(
ACCESS_CONTROL_ALLOW_CREDENTIALS,
HeaderValue::from_static("true"),
);
}
res.headers_mut().extend(headers);
Ok(res)
}
}
fn is_not_empty(h: &HeaderValue) -> bool {
!h.is_empty()
}
