From: Jeffrey Czyz <jkczyz@gmail.com>
Date: Wed, 26 May 2021 17:57:39 +0000 (-0700)
Subject: Parse RPC errors as JSON content
X-Git-Tag: v0.0.98~16^2
X-Git-Url: http://git.bitcoin.ninja/index.cgi?p=rust-lightning;a=commitdiff_plain;h=b2f16ad821672e07fd588beecd117206d9b656fd

Parse RPC errors as JSON content

Bitcoin Core's JSON RPC server returns errors as HTTP error responses
with JSON content in the body. Parse this content as JSON to give a more
meaningful error. Otherwise, "binary" is given because the content
contains ASCII control characters.
---

diff --git a/lightning-block-sync/src/rpc.rs b/lightning-block-sync/src/rpc.rs
index 66570bcb..88199688 100644
--- a/lightning-block-sync/src/rpc.rs
+++ b/lightning-block-sync/src/rpc.rs
@@ -2,7 +2,7 @@
 //! endpoint.
 
 use crate::{BlockHeaderData, BlockSource, AsyncBlockSourceResult};
-use crate::http::{HttpClient, HttpEndpoint, JsonResponse};
+use crate::http::{HttpClient, HttpEndpoint, HttpError, JsonResponse};
 
 use bitcoin::blockdata::block::Block;
 use bitcoin::hash_types::BlockHash;
@@ -47,8 +47,20 @@ impl RpcClient {
 			"id": &self.id.fetch_add(1, Ordering::AcqRel).to_string()
 		});
 
-		let mut response = self.client.post::<JsonResponse>(&uri, &host, &self.basic_auth, content)
-			.await?.0;
+		let mut response = match self.client.post::<JsonResponse>(&uri, &host, &self.basic_auth, content).await {
+			Ok(JsonResponse(response)) => response,
+			Err(e) if e.kind() == std::io::ErrorKind::Other => {
+				match e.get_ref().unwrap().downcast_ref::<HttpError>() {
+					Some(http_error) => match JsonResponse::try_from(http_error.contents.clone()) {
+						Ok(JsonResponse(response)) => response,
+						Err(_) => Err(e)?,
+					},
+					None => Err(e)?,
+				}
+			},
+			Err(e) => Err(e)?,
+		};
+
 		if !response.is_object() {
 			return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "expected JSON object"));
 		}
@@ -143,7 +155,7 @@ mod tests {
 		let response = serde_json::json!({
 			"error": { "code": -8, "message": "invalid parameter" },
 		});
-		let server = HttpServer::responding_with_ok(MessageBody::Content(response));
+		let server = HttpServer::responding_with_server_error(response);
 		let mut client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 
 		let invalid_block_hash = serde_json::json!("foo");