chore(docs): document the error types and variants in the errors mo…

…dule (#84)

src/errors.rs

@@ -1,74 +1,102 @@
+//! Error types.
 use std::io;
 
 use thiserror::Error;
 
 use near_jsonrpc_primitives::errors::{RpcError, RpcErrorKind, RpcRequestValidationErrorKind};
 use near_jsonrpc_primitives::message::{self, Message};
 
+/// Potential errors returned while sending a request to the RPC server.
 #[derive(Debug, Error)]
 pub enum JsonRpcTransportSendError {
+    /// Client is unable to serialize the request payload before sending it to the server.
     #[error("error while serializing payload: [{0}]")]
     PayloadSerializeError(io::Error),
+    /// Client is unable to send the request to the server.
     #[error("error while sending payload: [{0}]")]
     PayloadSendError(reqwest::Error),
 }
 
+/// Potential errors returned when the client has an issue parsing the response of a method call.
 #[derive(Debug, Error)]
 pub enum JsonRpcTransportHandlerResponseError {
+    /// Client fails to deserialize the result of a method call.
     #[error("error while parsing method call result: [{0}]")]
     ResultParseError(serde_json::Error),
+    /// Client fails to deserialize the error message returned from a method call.
     #[error("error while parsing method call error message: [{0}]")]
     ErrorMessageParseError(serde_json::Error),
 }
 
+/// Potential errors returned while receiving responses from an RPC server.
 #[derive(Debug, Error)]
 pub enum JsonRpcTransportRecvError {
+    /// Client receives a JSON RPC message body that isn't structured as a response.
     #[error("unexpected server response: [{0:?}]")]
     UnexpectedServerResponse(Message),
+    /// Client is unable to read the response from the RPC server.
     #[error("error while reading response: [{0}]")]
     PayloadRecvError(reqwest::Error),
+    /// The base response structure is malformed e.g. meta properties like RPC version are missing.
     #[error("error while parsing server response: [{0:?}]")]
     PayloadParseError(message::Broken),
+    /// Potential errors returned when the client has an issue parsing the response of a method call.
     #[error(transparent)]
     ResponseParseError(JsonRpcTransportHandlerResponseError),
 }
 
+/// Potential errors returned while sending requests to or receiving responses from the RPC server.
 #[derive(Debug, Error)]
 pub enum RpcTransportError {
+    /// Potential errors returned while sending a request to the RPC server.
     #[error(transparent)]
     SendError(JsonRpcTransportSendError),
+    /// Potential errors returned while receiving a response from an RPC server.
     #[error(transparent)]
     RecvError(JsonRpcTransportRecvError),
 }
 
+/// Unexpected status codes returned by the RPC server.
 #[derive(Debug, Error)]
 pub enum JsonRpcServerResponseStatusError {
+    /// The RPC client is unauthorized.
     #[error("this client is unauthorized")]
     Unauthorized,
+    /// The RPC client exceeds the rate limit by sending too many requests.
     #[error("this client has exceeded the rate limit")]
     TooManyRequests,
+    /// The RPC server returned a non-200 status code.
     #[error("the server returned a non-OK (200) status code: [{status}]")]
     Unexpected { status: reqwest::StatusCode },
 }
 
+/// Potential errors returned by the RPC server.
 #[derive(Debug, Error)]
 pub enum JsonRpcServerError<E> {
+    /// An invalid RPC method is called or the RPC methdo is unable to parse the provided arguments.
     #[error("request validation error: [{0:?}]")]
     RequestValidationError(RpcRequestValidationErrorKind),
+    /// RPC method call error.
     #[error("handler error: [{0}]")]
     HandlerError(E),
+    /// The RPC server returned an internal server error.
     #[error("internal error: [{info:?}]")]
     InternalError { info: Option<String> },
+    /// The RPC server returned a response without context i.e. a response the client doesn't expect.
     #[error("error response lacks context: {0}")]
     NonContextualError(RpcError),
+    /// Unexpected status codes returned by the RPC server.
     #[error(transparent)]
     ResponseStatusError(JsonRpcServerResponseStatusError),
 }
 
+/// Potential errors returned by the RPC client.
 #[derive(Debug, Error)]
 pub enum JsonRpcError<E> {
+    /// Potential errors returned while sending requests to or receiving responses from the RPC server.
     #[error(transparent)]
     TransportError(RpcTransportError),
+    /// Potential errors returned by the RPC server.
     #[error(transparent)]
     ServerError(JsonRpcServerError<E>),
 }