_ Git - rust-lightning/blob - lightning-block-sync/src/rpc.rs

   1 //! Simple RPC client implementation which implements [`BlockSource`] against a Bitcoin Core RPC
   2 //! endpoint.
   3
   4 use crate::{BlockData, BlockHeaderData, BlockSource, AsyncBlockSourceResult};
   5 use crate::http::{HttpClient, HttpEndpoint, HttpError, JsonResponse};
   6
   7 use bitcoin::hash_types::BlockHash;
   8 use bitcoin::hashes::hex::ToHex;
   9
  10 use futures_util::lock::Mutex;
  11
  12 use serde_json;
  13
  14 use std::convert::TryFrom;
  15 use std::convert::TryInto;
  16 use std::error::Error;
  17 use std::fmt;
  18 use std::sync::atomic::{AtomicUsize, Ordering};
  19
  20 /// An error returned by the RPC server.
  21 #[derive(Debug)]
  22 pub struct RpcError {
  23         /// The error code.
  24         pub code: i64,
  25         /// The error message.
  26         pub message: String,
  27 }
  28
  29 impl fmt::Display for RpcError {
  30     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  31         write!(f, "RPC error {}: {}", self.code, self.message)
  32     }
  33 }
  34
  35 impl Error for RpcError {}
  36
  37 /// A simple RPC client for calling methods using HTTP `POST`.
  38 pub struct RpcClient {
  39         basic_auth: String,
  40         endpoint: HttpEndpoint,
  41         client: Mutex<HttpClient>,
  42         id: AtomicUsize,
  43 }
  44
  45 impl RpcClient {
  46         /// Creates a new RPC client connected to the given endpoint with the provided credentials. The
  47         /// credentials should be a base64 encoding of a user name and password joined by a colon, as is
  48         /// required for HTTP basic access authentication.
  49         pub fn new(credentials: &str, endpoint: HttpEndpoint) -> std::io::Result<Self> {
  50                 let client = Mutex::new(HttpClient::connect(&endpoint)?);
  51                 Ok(Self {
  52                         basic_auth: "Basic ".to_string() + credentials,
  53                         endpoint,
  54                         client,
  55                         id: AtomicUsize::new(0),
  56                 })
  57         }
  58
  59         /// Calls a method with the response encoded in JSON format and interpreted as type `T`.
  60         pub async fn call_method<T>(&self, method: &str, params: &[serde_json::Value]) -> std::io::Result<T>
  61         where JsonResponse: TryFrom<Vec<u8>, Error = std::io::Error> + TryInto<T, Error = std::io::Error> {
  62                 let host = format!("{}:{}", self.endpoint.host(), self.endpoint.port());
  63                 let uri = self.endpoint.path();
  64                 let content = serde_json::json!({
  65                         "method": method,
  66                         "params": params,
  67                         "id": &self.id.fetch_add(1, Ordering::AcqRel).to_string()
  68                 });
  69
  70                 let mut response = match self.client.lock().await.post::<JsonResponse>(&uri, &host, &self.basic_auth, content).await {
  71                         Ok(JsonResponse(response)) => response,
  72                         Err(e) if e.kind() == std::io::ErrorKind::Other => {
  73                                 match e.get_ref().unwrap().downcast_ref::<HttpError>() {
  74                                         Some(http_error) => match JsonResponse::try_from(http_error.contents.clone()) {
  75                                                 Ok(JsonResponse(response)) => response,
  76                                                 Err(_) => Err(e)?,
  77                                         },
  78                                         None => Err(e)?,
  79                                 }
  80                         },
  81                         Err(e) => Err(e)?,
  82                 };
  83
  84                 if !response.is_object() {
  85                         return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "expected JSON object"));
  86                 }
  87
  88                 let error = &response["error"];
  89                 if !error.is_null() {
  90                         // TODO: Examine error code for a more precise std::io::ErrorKind.
  91                         let rpc_error = RpcError {
  92                                 code: error["code"].as_i64().unwrap_or(-1),
  93                                 message: error["message"].as_str().unwrap_or("unknown error").to_string()
  94                         };
  95                         return Err(std::io::Error::new(std::io::ErrorKind::Other, rpc_error));
  96                 }
  97
  98                 let result = &mut response["result"];
  99                 if result.is_null() {
 100                         return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "expected JSON result"));
 101                 }
 102
 103                 JsonResponse(result.take()).try_into()
 104         }
 105 }
 106
 107 impl BlockSource for RpcClient {
 108         fn get_header<'a>(&'a self, header_hash: &'a BlockHash, _height: Option<u32>) -> AsyncBlockSourceResult<'a, BlockHeaderData> {
 109                 Box::pin(async move {
 110                         let header_hash = serde_json::json!(header_hash.to_hex());
 111                         Ok(self.call_method("getblockheader", &[header_hash]).await?)
 112                 })
 113         }
 114
 115         fn get_block<'a>(&'a self, header_hash: &'a BlockHash) -> AsyncBlockSourceResult<'a, BlockData> {
 116                 Box::pin(async move {
 117                         let header_hash = serde_json::json!(header_hash.to_hex());
 118                         let verbosity = serde_json::json!(0);
 119                         Ok(BlockData::FullBlock(self.call_method("getblock", &[header_hash, verbosity]).await?))
 120                 })
 121         }
 122
 123         fn get_best_block<'a>(&'a self) -> AsyncBlockSourceResult<'a, (BlockHash, Option<u32>)> {
 124                 Box::pin(async move {
 125                         Ok(self.call_method("getblockchaininfo", &[]).await?)
 126                 })
 127         }
 128 }
 129
 130 #[cfg(test)]
 131 mod tests {
 132         use super::*;
 133         use crate::http::client_tests::{HttpServer, MessageBody};
 134
 135         /// Credentials encoded in base64.
 136         const CREDENTIALS: &'static str = "dXNlcjpwYXNzd29yZA==";
 137
 138         /// Converts a JSON value into `u64`.
 139         impl TryInto<u64> for JsonResponse {
 140                 type Error = std::io::Error;
 141
 142                 fn try_into(self) -> std::io::Result<u64> {
 143                         match self.0.as_u64() {
 144                                 None => Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "not a number")),
 145                                 Some(n) => Ok(n),
 146                         }
 147                 }
 148         }
 149
 150         #[tokio::test]
 151         async fn call_method_returning_unknown_response() {
 152                 let server = HttpServer::responding_with_not_found();
 153                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 154
 155                 match client.call_method::<u64>("getblockcount", &[]).await {
 156                         Err(e) => assert_eq!(e.kind(), std::io::ErrorKind::Other),
 157                         Ok(_) => panic!("Expected error"),
 158                 }
 159         }
 160
 161         #[tokio::test]
 162         async fn call_method_returning_malfomred_response() {
 163                 let response = serde_json::json!("foo");
 164                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 165                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 166
 167                 match client.call_method::<u64>("getblockcount", &[]).await {
 168                         Err(e) => {
 169                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 170                                 assert_eq!(e.get_ref().unwrap().to_string(), "expected JSON object");
 171                         },
 172                         Ok(_) => panic!("Expected error"),
 173                 }
 174         }
 175
 176         #[tokio::test]
 177         async fn call_method_returning_error() {
 178                 let response = serde_json::json!({
 179                         "error": { "code": -8, "message": "invalid parameter" },
 180                 });
 181                 let server = HttpServer::responding_with_server_error(response);
 182                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 183
 184                 let invalid_block_hash = serde_json::json!("foo");
 185                 match client.call_method::<u64>("getblock", &[invalid_block_hash]).await {
 186                         Err(e) => {
 187                                 assert_eq!(e.kind(), std::io::ErrorKind::Other);
 188                                 let rpc_error: Box<RpcError> = e.into_inner().unwrap().downcast().unwrap();
 189                                 assert_eq!(rpc_error.code, -8);
 190                                 assert_eq!(rpc_error.message, "invalid parameter");
 191                         },
 192                         Ok(_) => panic!("Expected error"),
 193                 }
 194         }
 195
 196         #[tokio::test]
 197         async fn call_method_returning_missing_result() {
 198                 let response = serde_json::json!({ "result": null });
 199                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 200                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 201
 202                 match client.call_method::<u64>("getblockcount", &[]).await {
 203                         Err(e) => {
 204                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 205                                 assert_eq!(e.get_ref().unwrap().to_string(), "expected JSON result");
 206                         },
 207                         Ok(_) => panic!("Expected error"),
 208                 }
 209         }
 210
 211         #[tokio::test]
 212         async fn call_method_returning_malformed_result() {
 213                 let response = serde_json::json!({ "result": "foo" });
 214                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 215                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 216
 217                 match client.call_method::<u64>("getblockcount", &[]).await {
 218                         Err(e) => {
 219                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 220                                 assert_eq!(e.get_ref().unwrap().to_string(), "not a number");
 221                         },
 222                         Ok(_) => panic!("Expected error"),
 223                 }
 224         }
 225
 226         #[tokio::test]
 227         async fn call_method_returning_valid_result() {
 228                 let response = serde_json::json!({ "result": 654470 });
 229                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 230                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 231
 232                 match client.call_method::<u64>("getblockcount", &[]).await {
 233                         Err(e) => panic!("Unexpected error: {:?}", e),
 234                         Ok(count) => assert_eq!(count, 654470),
 235                 }
 236         }
 237 }