Better way of JsonRpseeError creation

crates/author-ext-rpc/Cargo.toml

@@ -8,11 +8,17 @@ publish = false
 author-ext-api = { version = "0.1", path = "../author-ext-api" }
 bioauth-keys = { version = "0.1", path = "../bioauth-keys" }
 rpc-deny-unsafe = { path = "../rpc-deny-unsafe" }
+rpc-error-response = { path = "../rpc-error-response" }
+rpc-validator-key-logic = { version = "0.1", path = "../rpc-validator-key-logic" }
 
 jsonrpsee = { version = "0.15.1", features = ["server", "macros"] }
 sc-transaction-pool-api = { git = "https://github.com/humanode-network/substrate", branch = "locked/humanode-2022-11-23" }
+serde = "1"
 sp-api = { git = "https://github.com/humanode-network/substrate", branch = "locked/humanode-2022-11-23" }
 sp-blockchain = { git = "https://github.com/humanode-network/substrate", branch = "locked/humanode-2022-11-23" }
 sp-core = { git = "https://github.com/humanode-network/substrate", branch = "locked/humanode-2022-11-23" }
 sp-runtime = { git = "https://github.com/humanode-network/substrate", branch = "locked/humanode-2022-11-23" }
 tracing = "0.1"
+
+[dev-dependencies]
+serde_json = "1"

crates/author-ext-rpc/src/error_data.rs

@@ -0,0 +1,23 @@
+//! The shapes and variants of the custom error data.
+
+use serde::Serialize;
+
+/// The RPC error context we provide to describe transaction pool errors.
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct AuthorExtTxErrorDetails {
+    /// The error kind.
+    pub kind: AuthorExtTxErrorKind,
+    /// The human-friendly message for what happened.
+    pub message: &'static str,
+    /// The message from the inner transaction pool error.
+    pub inner_error: String,
+}
+
+/// The error kinds that we expose in the RPC that originate from the transaction pool.
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "SCREAMING_SNAKE_CASE")]
+pub enum AuthorExtTxErrorKind {
+    /// The inability to pay some fees (e.g. account balance too low).
+    NoFunds,
+}

crates/author-ext-rpc/src/errors/get_validator_public_key.rs

@@ -0,0 +1,66 @@
+//! The `get_validator_public_key` method error.
+
+use rpc_validator_key_logic::Error as ValidatorKeyError;
+
+use super::api_error_code;
+
+/// The `get_validator_public_key` method error kinds.
+#[derive(Debug)]
+pub enum Error {
+    /// An error that can occur during validator key extraction.
+    KeyExtraction(ValidatorKeyError),
+}
+
+impl From<Error> for jsonrpsee::core::Error {
+    fn from(err: Error) -> Self {
+        match err {
+            Error::KeyExtraction(err @ ValidatorKeyError::MissingValidatorKey) => {
+                rpc_error_response::data(
+                    api_error_code::MISSING_VALIDATOR_KEY,
+                    err.to_string(),
+                    rpc_validator_key_logic::error_data::ValidatorKeyNotAvailable,
+                )
+            }
+            Error::KeyExtraction(err @ ValidatorKeyError::ValidatorKeyExtraction) => {
+                rpc_error_response::simple(
+                    api_error_code::VALIDATOR_KEY_EXTRACTION,
+                    err.to_string(),
+                )
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    use jsonrpsee::types::ErrorObject;
+
+    use super::*;
+
+    #[test]
+    fn error_key_extraction_validator_key_extraction() {
+        let error: jsonrpsee::core::Error =
+            Error::KeyExtraction(ValidatorKeyError::ValidatorKeyExtraction).into();
+        let error: ErrorObject = error.into();
+
+        let expected_error_message = "{\"code\":600,\"message\":\"unable to extract own key\"}";
+        assert_eq!(
+            expected_error_message,
+            serde_json::to_string(&error).unwrap()
+        );
+    }
+
+    #[test]
+    fn error_key_extraction_missing_validator_key() {
+        let error: jsonrpsee::core::Error =
+            Error::KeyExtraction(ValidatorKeyError::MissingValidatorKey).into();
+        let error: ErrorObject = error.into();
+
+        let expected_error_message = "{\"code\":500,\"message\":\"validator key not available\",\"data\":{\"validatorKeyNotAvailable\":true}}";
+        assert_eq!(
+            expected_error_message,
+            serde_json::to_string(&error).unwrap()
+        );
+    }
+}

crates/author-ext-rpc/src/errors/mod.rs

@@ -0,0 +1,21 @@
+//! All author extension related error kinds that we expose in the RPC.
+
+pub mod get_validator_public_key;
+pub mod set_keys;
+
+/// Custom rpc error codes.
+pub mod api_error_code {
+    /// Call to runtime api has failed.
+    pub const RUNTIME_API: i32 = 300;
+
+    /// Authenticate transaction has failed.
+    pub const TRANSACTION: i32 = 400;
+
+    /// Validator key is not available.
+    pub const MISSING_VALIDATOR_KEY: i32 =
+        rpc_validator_key_logic::api_error_code::MISSING_VALIDATOR_KEY;
+
+    /// Validator key extraction has failed.
+    pub const VALIDATOR_KEY_EXTRACTION: i32 =
+        rpc_validator_key_logic::api_error_code::VALIDATOR_KEY_EXTRACTION;
+}