Assume Content-Type is json for endpoints that require json (#4575)

* added default content type filter

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into unstable

* create custom warp json filter that ignores content type header

* cargo fmt and linting

* updated test

* updated test

* merge unstable

* merge conflicts

* workspace=true

* use Bytes instead of Buf

* resolve merge conflict

* resolve merge conflicts

* add extra error message context

* merge conflicts

* lint

common/eth2/src/lib.rs

@@ -373,10 +373,30 @@ impl BeaconNodeHttpClient {
         if let Some(timeout) = timeout {
             builder = builder.timeout(timeout);
         }
+
         let response = builder.json(body).send().await?;
         ok_or_error(response).await
     }
 
+    /// Generic POST function supporting arbitrary responses and timeouts.
+    /// Does not include Content-Type application/json in the request header.
+    async fn post_generic_json_without_content_type_header<T: Serialize, U: IntoUrl>(
+        &self,
+        url: U,
+        body: &T,
+        timeout: Option<Duration>,
+    ) -> Result<Response, Error> {
+        let mut builder = self.client.post(url);
+        if let Some(timeout) = timeout {
+            builder = builder.timeout(timeout);
+        }
+
+        let serialized_body = serde_json::to_vec(body).map_err(Error::InvalidJson)?;
+
+        let response = builder.body(serialized_body).send().await?;
+        ok_or_error(response).await
+    }
+
     /// Generic POST function supporting arbitrary responses and timeouts.
     async fn post_generic_with_consensus_version<T: Serialize, U: IntoUrl>(
         &self,
@@ -1250,7 +1270,8 @@ impl BeaconNodeHttpClient {
             .push("pool")
             .push("attester_slashings");
 
-        self.post(path, slashing).await?;
+        self.post_generic_json_without_content_type_header(path, slashing, None)
+            .await?;
 
         Ok(())
     }

common/warp_utils/Cargo.toml

@@ -14,8 +14,10 @@ beacon_chain = { workspace = true }
 state_processing = { workspace = true }
 safe_arith = { workspace = true }
 serde = { workspace = true }
+serde_json = { workspace = true }
 tokio = { workspace = true }
 headers = "0.3.2"
 lighthouse_metrics = { workspace = true }
 lazy_static = { workspace = true }
 serde_array_query = "0.1.0"
+bytes = { workspace = true }

common/warp_utils/src/json.rs

@@ -0,0 +1,22 @@
+use bytes::Bytes;
+use serde::de::DeserializeOwned;
+use std::error::Error as StdError;
+use warp::{Filter, Rejection};
+
+use crate::reject;
+
+struct Json;
+
+type BoxError = Box<dyn StdError + Send + Sync>;
+
+impl Json {
+    fn decode<T: DeserializeOwned>(bytes: Bytes) -> Result<T, BoxError> {
+        serde_json::from_slice(&bytes).map_err(Into::into)
+    }
+}
+
+pub fn json<T: DeserializeOwned + Send>() -> impl Filter<Extract = (T,), Error = Rejection> + Copy {
+    warp::body::bytes().and_then(|bytes: Bytes| async move {
+        Json::decode(bytes).map_err(|err| reject::custom_deserialize_error(format!("{:?}", err)))
+    })
+}

common/warp_utils/src/lib.rs

@@ -2,6 +2,7 @@
 //! Lighthouse project. E.g., the `http_api` and `http_metrics` crates.
 
 pub mod cors;
+pub mod json;
 pub mod metrics;
 pub mod query;
 pub mod reject;

common/warp_utils/src/reject.rs

@@ -82,6 +82,15 @@ pub fn custom_bad_request(msg: String) -> warp::reject::Rejection {
     warp::reject::custom(CustomBadRequest(msg))
 }
 
+#[derive(Debug)]
+pub struct CustomDeserializeError(pub String);
+
+impl Reject for CustomDeserializeError {}
+
+pub fn custom_deserialize_error(msg: String) -> warp::reject::Rejection {
+    warp::reject::custom(CustomDeserializeError(msg))
+}
+
 #[derive(Debug)]
 pub struct CustomServerError(pub String);
 
@@ -161,6 +170,9 @@ pub async fn handle_rejection(err: warp::Rejection) -> Result<impl warp::Reply,
     if err.is_not_found() {
         code = StatusCode::NOT_FOUND;
         message = "NOT_FOUND".to_string();
+    } else if let Some(e) = err.find::<crate::reject::CustomDeserializeError>() {
+        message = format!("BAD_REQUEST: body deserialize error: {}", e.0);
+        code = StatusCode::BAD_REQUEST;
     } else if let Some(e) = err.find::<warp::filters::body::BodyDeserializeError>() {
         message = format!("BAD_REQUEST: body deserialize error: {}", e);
         code = StatusCode::BAD_REQUEST;