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 66570bcb57c032353ab0d6a2f500bcda91740381..88199688aefd1a48fd128aac5c45f319f947c90e 100644 (file)
--- 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");