feat: customizable JSON-RPC error codes via new enum variant on `Call…

…Errror` (#394)

* feat: customizable error via RpcError trait

This commit introduces a new trait for defining user customizable error codes and messages

* revert trait stuff

* use RawValue

* fix docs

* rexport to_json_raw_value

types/src/error.rs

@@ -1,4 +1,5 @@
 use serde::{Deserialize, Serialize};
+use serde_json::value::RawValue;
 use std::fmt;
 
 /// Convenience type for displaying errors.
@@ -19,12 +20,22 @@ impl<T: fmt::Display> fmt::Display for Mismatch<T> {
 /// Error that occurs when a call failed.
 #[derive(Debug, thiserror::Error)]
 pub enum CallError {
-	#[error("Invalid params in the RPC call")]
 	/// Invalid params in the call.
+	#[error("Invalid params in the call")]
 	InvalidParams,
+	/// The call failed (let jsonrpsee assign default error code and error message).
 	#[error("RPC Call failed: {0}")]
-	/// The call failed.
-	Failed(#[source] Box<dyn std::error::Error + Send + Sync>),
+	Failed(Box<dyn std::error::Error + Send + Sync>),
+	/// Custom error with specific JSON-RPC error code, message and data.
+	#[error("RPC Call failed: code: {code}, message: {message}, data: {data:?}")]
+	Custom {
+		/// JSON-RPC error code
+		code: i32,
+		/// Short description of the error.
+		message: String,
+		/// A primitive or structured value that contains additional information about the error.
+		data: Option<Box<RawValue>>,
+	},
 }
 
 /// Error type.

types/src/lib.rs

@@ -24,4 +24,7 @@ pub use beef::Cow;
 pub use client::*;
 pub use error::Error;
 pub use serde::{de::DeserializeOwned, Serialize};
-pub use serde_json::{to_value as to_json_value, value::RawValue as JsonRawValue, Value as JsonValue};
+pub use serde_json::{
+	to_value as to_json_value, value::to_raw_value as to_json_raw_value, value::RawValue as JsonRawValue,
+	Value as JsonValue,
+};

utils/src/server/rpc_module.rs

@@ -69,7 +69,7 @@ impl MethodCallback {
 
 		if let Err(err) = result {
 			log::error!("execution of method call '{}' failed: {:?}, request id={:?}", req.method, err, id);
-			send_error(id, &tx, JsonRpcErrorCode::ServerError(-1).into());
+			send_error(id, tx, JsonRpcErrorCode::ServerError(-1).into());
 		}
 	}
 }
@@ -190,14 +190,18 @@ impl<Context: Send + Sync + 'static> RpcModule<Context> {
 				match callback(params, &*ctx) {
 					Ok(res) => send_response(id, tx, res),
 					Err(CallError::InvalidParams) => send_error(id, tx, JsonRpcErrorCode::InvalidParams.into()),
-					Err(CallError::Failed(err)) => {
+					Err(CallError::Failed(e)) => {
 						let err = JsonRpcErrorObject {
 							code: JsonRpcErrorCode::ServerError(CALL_EXECUTION_FAILED_CODE),
-							message: &err.to_string(),
+							message: &e.to_string(),
 							data: None,
 						};
 						send_error(id, tx, err)
 					}
+					Err(CallError::Custom { code, message, data }) => {
+						let err = JsonRpcErrorObject { code: code.into(), message: &message, data: data.as_deref() };
+						send_error(id, tx, err)
+					}
 				};
 
 				Ok(())
@@ -227,15 +231,19 @@ impl<Context: Send + Sync + 'static> RpcModule<Context> {
 					match callback(params, ctx).await {
 						Ok(res) => send_response(id, &tx, res),
 						Err(CallError::InvalidParams) => send_error(id, &tx, JsonRpcErrorCode::InvalidParams.into()),
-						Err(CallError::Failed(err)) => {
-							log::error!("Call failed with: {}", err);
+						Err(CallError::Failed(e)) => {
 							let err = JsonRpcErrorObject {
 								code: JsonRpcErrorCode::ServerError(CALL_EXECUTION_FAILED_CODE),
-								message: &err.to_string(),
+								message: &e.to_string(),
 								data: None,
 							};
 							send_error(id, &tx, err)
 						}
+						Err(CallError::Custom { code, message, data }) => {
+							let err =
+								JsonRpcErrorObject { code: code.into(), message: &message, data: data.as_deref() };
+							send_error(id, &tx, err)
+						}
 					};
 					Ok(())
 				};
@@ -323,7 +331,7 @@ impl<Context: Send + Sync + 'static> RpcModule<Context> {
 				MethodCallback::Sync(Arc::new(move |id, params, tx, conn_id| {
 					let sub_id = params.one()?;
 					subscribers.lock().remove(&SubscriptionKey { conn_id, sub_id });
-					send_response(id, &tx, "Unsubscribed");
+					send_response(id, tx, "Unsubscribed");
 
 					Ok(())
 				})),