refactor: move ratelimits to a generic system for all web servers

crates/core/ratelimits/src/rocket.rs

@@ -0,0 +1,162 @@
+use async_trait::async_trait;
+use log::info;
+use rocket::fairing::{Fairing, Info, Kind};
+use rocket::http::uri::Origin;
+use rocket::http::{Method, Status};
+use rocket::request::{FromRequest, Outcome};
+use rocket::serde::json::Json;
+use rocket::{Data, Request, Response, State};
+
+use revolt_rocket_okapi::r#gen::OpenApiGenerator;
+use revolt_rocket_okapi::request::{OpenApiFromRequest, RequestHeaderInput};
+
+use authifier::models::Session;
+
+use crate::ratelimiter::RequestKind;
+use crate::ratelimiter::{RatelimitInformation, Ratelimiter};
+
+#[derive(Clone, Copy)]
+pub struct RocketRequestKind;
+
+impl RequestKind for RocketRequestKind {
+    type R<'a> = Request<'a>;
+}
+
+pub type RatelimitStorage = crate::ratelimiter::RatelimitStorage<RocketRequestKind>;
+
+/// Find the remote IP of the client
+fn to_ip(request: &'_ rocket::Request<'_>) -> String {
+    request
+        .remote()
+        .map(|x| x.ip().to_string())
+        .unwrap_or_default()
+}
+
+/// Find the actual IP of the client
+fn to_real_ip(request: &'_ rocket::Request<'_>) -> String {
+    if let Ok(true) = std::env::var("TRUST_CLOUDFLARE").map(|x| x == "1") {
+        request
+            .headers()
+            .get_one("CF-Connecting-IP")
+            .map(|x| x.to_string())
+            .unwrap_or_else(|| to_ip(request))
+    } else {
+        to_ip(request)
+    }
+}
+
+#[async_trait]
+impl<'r> FromRequest<'r> for Ratelimiter {
+    type Error = Ratelimiter;
+
+    async fn from_request<'a>(request: &'r rocket::Request<'a>) -> Outcome<Self, Self::Error> {
+        let ratelimiter = request
+            .local_cache_async(async {
+                use rocket::outcome::Outcome;
+
+                let storage = request.guard::<&State<RatelimitStorage>>().await.unwrap();
+
+                let identifier = if let Outcome::Success(session) = request.guard::<Session>().await
+                {
+                    session.id
+                } else {
+                    to_real_ip(request)
+                };
+
+                let (bucket, resource) = storage.resolver.resolve_bucket(request);
+                let limit = storage.resolver.resolve_bucket_limit(bucket);
+
+                Ratelimiter::from(&storage.map, &identifier, limit, (bucket, resource))
+            })
+            .await;
+
+        match ratelimiter {
+            Ok(ratelimiter) => Outcome::Success(*ratelimiter),
+            Err(ratelimiter) => Outcome::Error((Status::TooManyRequests, *ratelimiter)),
+        }
+    }
+}
+
+impl OpenApiFromRequest<'_> for Ratelimiter {
+    fn from_request_input(
+        _gen: &mut OpenApiGenerator,
+        _name: String,
+        _required: bool,
+    ) -> revolt_rocket_okapi::Result<RequestHeaderInput> {
+        Ok(RequestHeaderInput::None)
+    }
+}
+
+/// Attach ratelimiter to the Rocket application
+pub struct RatelimitFairing;
+
+#[async_trait]
+impl Fairing for RatelimitFairing {
+    fn info(&self) -> Info {
+        Info {
+            name: "Ratelimiter",
+            kind: Kind::Request | Kind::Response,
+        }
+    }
+
+    async fn on_request(&self, request: &mut Request<'_>, _: &mut Data<'_>) {
+        use rocket::outcome::Outcome;
+        if let Outcome::Error(_) = request.guard::<Ratelimiter>().await {
+            info!(
+                "User rate-limited on route {}! (IP = {:?})",
+                request.uri(),
+                to_real_ip(request)
+            );
+
+            request.set_method(Method::Get);
+            request.set_uri(Origin::parse("/ratelimit").unwrap())
+        }
+    }
+
+    async fn on_response<'r>(&self, request: &'r Request<'_>, response: &mut Response<'r>) {
+        let guard = request.guard::<Ratelimiter>().await;
+        let (Outcome::Success(ratelimiter) | Outcome::Error((_, ratelimiter))) = guard else {
+            unreachable!()
+        };
+        let Ratelimiter {
+            key,
+            limit,
+            remaining,
+            reset,
+        } = ratelimiter;
+
+        response.set_raw_header("X-RateLimit-Limit", limit.to_string());
+        response.set_raw_header("X-RateLimit-Bucket", key.to_string());
+        response.set_raw_header("X-RateLimit-Remaining", remaining.to_string());
+        response.set_raw_header("X-RateLimit-Reset-After", reset.to_string());
+
+        if guard.is_error() {
+            response.set_status(Status::TooManyRequests);
+        }
+    }
+}
+
+#[async_trait]
+impl<'r> FromRequest<'r> for RatelimitInformation {
+    type Error = u128;
+
+    async fn from_request(request: &'r rocket::Request<'_>) -> Outcome<Self, Self::Error> {
+        let info = match request.guard::<Ratelimiter>().await {
+            Outcome::Success(ratelimiter) => RatelimitInformation::Success(ratelimiter),
+            Outcome::Error((_, ratelimiter)) => RatelimitInformation::Failure {
+                retry_after: ratelimiter.reset,
+            },
+            _ => unreachable!(),
+        };
+        Outcome::Success(info)
+    }
+}
+
+#[rocket::get("/ratelimit")]
+fn ratelimit_info(info: RatelimitInformation) -> Json<RatelimitInformation> {
+    Json(info)
+}
+
+pub fn routes() -> Vec<rocket::Route> {
+    rocket::routes![ratelimit_info]
+}