_ 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 ///
  39 /// Implements [`BlockSource`] and may return an `Err` containing [`RpcError`]. See
  40 /// [`RpcClient::call_method`] for details.
  41 pub struct RpcClient {
  42         basic_auth: String,
  43         endpoint: HttpEndpoint,
  44         client: Mutex<HttpClient>,
  45         id: AtomicUsize,
  46 }
  47
  48 impl RpcClient {
  49         /// Creates a new RPC client connected to the given endpoint with the provided credentials. The
  50         /// credentials should be a base64 encoding of a user name and password joined by a colon, as is
  51         /// required for HTTP basic access authentication.
  52         pub fn new(credentials: &str, endpoint: HttpEndpoint) -> std::io::Result<Self> {
  53                 let client = Mutex::new(HttpClient::connect(&endpoint)?);
  54                 Ok(Self {
  55                         basic_auth: "Basic ".to_string() + credentials,
  56                         endpoint,
  57                         client,
  58                         id: AtomicUsize::new(0),
  59                 })
  60         }
  61
  62         /// Calls a method with the response encoded in JSON format and interpreted as type `T`.
  63         ///
  64         /// When an `Err` is returned, [`std::io::Error::into_inner`] may contain an [`RpcError`] if
  65         /// [`std::io::Error::kind`] is [`std::io::ErrorKind::Other`].
  66         pub async fn call_method<T>(&self, method: &str, params: &[serde_json::Value]) -> std::io::Result<T>
  67         where JsonResponse: TryFrom<Vec<u8>, Error = std::io::Error> + TryInto<T, Error = std::io::Error> {
  68                 let host = format!("{}:{}", self.endpoint.host(), self.endpoint.port());
  69                 let uri = self.endpoint.path();
  70                 let content = serde_json::json!({
  71                         "method": method,
  72                         "params": params,
  73                         "id": &self.id.fetch_add(1, Ordering::AcqRel).to_string()
  74                 });
  75
  76                 let mut response = match self.client.lock().await.post::<JsonResponse>(&uri, &host, &self.basic_auth, content).await {
  77                         Ok(JsonResponse(response)) => response,
  78                         Err(e) if e.kind() == std::io::ErrorKind::Other => {
  79                                 match e.get_ref().unwrap().downcast_ref::<HttpError>() {
  80                                         Some(http_error) => match JsonResponse::try_from(http_error.contents.clone()) {
  81                                                 Ok(JsonResponse(response)) => response,
  82                                                 Err(_) => Err(e)?,
  83                                         },
  84                                         None => Err(e)?,
  85                                 }
  86                         },
  87                         Err(e) => Err(e)?,
  88                 };
  89
  90                 if !response.is_object() {
  91                         return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "expected JSON object"));
  92                 }
  93
  94                 let error = &response["error"];
  95                 if !error.is_null() {
  96                         // TODO: Examine error code for a more precise std::io::ErrorKind.
  97                         let rpc_error = RpcError {
  98                                 code: error["code"].as_i64().unwrap_or(-1),
  99                                 message: error["message"].as_str().unwrap_or("unknown error").to_string()
 100                         };
 101                         return Err(std::io::Error::new(std::io::ErrorKind::Other, rpc_error));
 102                 }
 103
 104                 let result = &mut response["result"];
 105                 if result.is_null() {
 106                         return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "expected JSON result"));
 107                 }
 108
 109                 JsonResponse(result.take()).try_into()
 110         }
 111 }
 112
 113 impl BlockSource for RpcClient {
 114         fn get_header<'a>(&'a self, header_hash: &'a BlockHash, _height: Option<u32>) -> AsyncBlockSourceResult<'a, BlockHeaderData> {
 115                 Box::pin(async move {
 116                         let header_hash = serde_json::json!(header_hash.to_hex());
 117                         Ok(self.call_method("getblockheader", &[header_hash]).await?)
 118                 })
 119         }
 120
 121         fn get_block<'a>(&'a self, header_hash: &'a BlockHash) -> AsyncBlockSourceResult<'a, BlockData> {
 122                 Box::pin(async move {
 123                         let header_hash = serde_json::json!(header_hash.to_hex());
 124                         let verbosity = serde_json::json!(0);
 125                         Ok(BlockData::FullBlock(self.call_method("getblock", &[header_hash, verbosity]).await?))
 126                 })
 127         }
 128
 129         fn get_best_block<'a>(&'a self) -> AsyncBlockSourceResult<'a, (BlockHash, Option<u32>)> {
 130                 Box::pin(async move {
 131                         Ok(self.call_method("getblockchaininfo", &[]).await?)
 132                 })
 133         }
 134 }
 135
 136 #[cfg(test)]
 137 mod tests {
 138         use super::*;
 139         use crate::http::client_tests::{HttpServer, MessageBody};
 140
 141         /// Credentials encoded in base64.
 142         const CREDENTIALS: &'static str = "dXNlcjpwYXNzd29yZA==";
 143
 144         /// Converts a JSON value into `u64`.
 145         impl TryInto<u64> for JsonResponse {
 146                 type Error = std::io::Error;
 147
 148                 fn try_into(self) -> std::io::Result<u64> {
 149                         match self.0.as_u64() {
 150                                 None => Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "not a number")),
 151                                 Some(n) => Ok(n),
 152                         }
 153                 }
 154         }
 155
 156         #[tokio::test]
 157         async fn call_method_returning_unknown_response() {
 158                 let server = HttpServer::responding_with_not_found();
 159                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 160
 161                 match client.call_method::<u64>("getblockcount", &[]).await {
 162                         Err(e) => assert_eq!(e.kind(), std::io::ErrorKind::Other),
 163                         Ok(_) => panic!("Expected error"),
 164                 }
 165         }
 166
 167         #[tokio::test]
 168         async fn call_method_returning_malfomred_response() {
 169                 let response = serde_json::json!("foo");
 170                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 171                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 172
 173                 match client.call_method::<u64>("getblockcount", &[]).await {
 174                         Err(e) => {
 175                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 176                                 assert_eq!(e.get_ref().unwrap().to_string(), "expected JSON object");
 177                         },
 178                         Ok(_) => panic!("Expected error"),
 179                 }
 180         }
 181
 182         #[tokio::test]
 183         async fn call_method_returning_error() {
 184                 let response = serde_json::json!({
 185                         "error": { "code": -8, "message": "invalid parameter" },
 186                 });
 187                 let server = HttpServer::responding_with_server_error(response);
 188                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 189
 190                 let invalid_block_hash = serde_json::json!("foo");
 191                 match client.call_method::<u64>("getblock", &[invalid_block_hash]).await {
 192                         Err(e) => {
 193                                 assert_eq!(e.kind(), std::io::ErrorKind::Other);
 194                                 let rpc_error: Box<RpcError> = e.into_inner().unwrap().downcast().unwrap();
 195                                 assert_eq!(rpc_error.code, -8);
 196                                 assert_eq!(rpc_error.message, "invalid parameter");
 197                         },
 198                         Ok(_) => panic!("Expected error"),
 199                 }
 200         }
 201
 202         #[tokio::test]
 203         async fn call_method_returning_missing_result() {
 204                 let response = serde_json::json!({ "result": null });
 205                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 206                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 207
 208                 match client.call_method::<u64>("getblockcount", &[]).await {
 209                         Err(e) => {
 210                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 211                                 assert_eq!(e.get_ref().unwrap().to_string(), "expected JSON result");
 212                         },
 213                         Ok(_) => panic!("Expected error"),
 214                 }
 215         }
 216
 217         #[tokio::test]
 218         async fn call_method_returning_malformed_result() {
 219                 let response = serde_json::json!({ "result": "foo" });
 220                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 221                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 222
 223                 match client.call_method::<u64>("getblockcount", &[]).await {
 224                         Err(e) => {
 225                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 226                                 assert_eq!(e.get_ref().unwrap().to_string(), "not a number");
 227                         },
 228                         Ok(_) => panic!("Expected error"),
 229                 }
 230         }
 231
 232         #[tokio::test]
 233         async fn call_method_returning_valid_result() {
 234                 let response = serde_json::json!({ "result": 654470 });
 235                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 236                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 237
 238                 match client.call_method::<u64>("getblockcount", &[]).await {
 239                         Err(e) => panic!("Unexpected error: {:?}", e),
 240                         Ok(count) => assert_eq!(count, 654470),
 241                 }
 242         }
 243 }