Add bones of execution_layer

beacon_node/execution_layer/src/engine_api/http.rs

@@ -0,0 +1,73 @@
+use super::*;
+use async_trait::async_trait;
+use eth1::http::{hex_to_u64_be, response_result_or_error, send_rpc_request};
+pub use reqwest::Client;
+use sensitive_url::SensitiveUrl;
+use serde::{Deserialize, Serialize};
+use serde_json::json;
+use std::time::Duration;
+
+const ENGINE_PREPARE_PAYLOAD: &str = "engine_preparePayload";
+const ENGINE_PREPARE_PAYLOAD_TIMEOUT: Duration = Duration::from_millis(500);
+
+pub struct HttpJsonRpc {
+    pub client: Client,
+    pub url: SensitiveUrl,
+}
+
+impl HttpJsonRpc {
+    pub fn new(url: SensitiveUrl) -> Result<Self, Error> {
+        Ok(Self {
+            client: Client::builder().build()?,
+            url,
+        })
+    }
+}
+
+#[async_trait]
+impl EngineApi for HttpJsonRpc {
+    async fn upcheck(&self) -> Result<(), Error> {
+        todo!()
+    }
+
+    async fn prepare_payload(
+        &self,
+        parent_hash: Hash256,
+        timestamp: u64,
+        random: Hash256,
+        fee_recipient: Address,
+    ) -> Result<PayloadId, Error> {
+        let params = json!([PreparePayloadRequest {
+            parent_hash,
+            timestamp,
+            random,
+            fee_recipient
+        }]);
+
+        let response_body = send_rpc_request(
+            &self.url,
+            ENGINE_PREPARE_PAYLOAD,
+            params,
+            ENGINE_PREPARE_PAYLOAD_TIMEOUT,
+        )
+        .await
+        .map_err(Error::RequestFailed)?;
+
+        let result = response_result_or_error(&response_body).map_err(Error::JsonRpc)?;
+        let string = result
+            .as_str()
+            .ok_or(Error::BadResponse("data was not string".to_string()))?;
+
+        hex_to_u64_be(string).map_err(Error::BadResponse)
+    }
+}
+
+#[derive(Debug, PartialEq, Serialize, Deserialize)]
+#[serde(rename = "camelCase")]
+struct PreparePayloadRequest {
+    parent_hash: Hash256,
+    #[serde(with = "eth2_serde_utils::u64_hex_be")]
+    timestamp: u64,
+    random: Hash256,
+    fee_recipient: Address,
+}