_ 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 std::sync::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<Option<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                 Ok(Self {
  54                         basic_auth: "Basic ".to_string() + credentials,
  55                         endpoint,
  56                         client: Mutex::new(None),
  57                         id: AtomicUsize::new(0),
  58                 })
  59         }
  60
  61         /// Calls a method with the response encoded in JSON format and interpreted as type `T`.
  62         ///
  63         /// When an `Err` is returned, [`std::io::Error::into_inner`] may contain an [`RpcError`] if
  64         /// [`std::io::Error::kind`] is [`std::io::ErrorKind::Other`].
  65         pub async fn call_method<T>(&self, method: &str, params: &[serde_json::Value]) -> std::io::Result<T>
  66         where JsonResponse: TryFrom<Vec<u8>, Error = std::io::Error> + TryInto<T, Error = std::io::Error> {
  67                 let host = format!("{}:{}", self.endpoint.host(), self.endpoint.port());
  68                 let uri = self.endpoint.path();
  69                 let content = serde_json::json!({
  70                         "method": method,
  71                         "params": params,
  72                         "id": &self.id.fetch_add(1, Ordering::AcqRel).to_string()
  73                 });
  74
  75                 let mut client = if let Some(client) = self.client.lock().unwrap().take() { client }
  76                         else { HttpClient::connect(&self.endpoint)? };
  77                 let http_response = client.post::<JsonResponse>(&uri, &host, &self.basic_auth, content).await;
  78                 *self.client.lock().unwrap() = Some(client);
  79
  80                 let mut response = match http_response {
  81                         Ok(JsonResponse(response)) => response,
  82                         Err(e) if e.kind() == std::io::ErrorKind::Other => {
  83                                 match e.get_ref().unwrap().downcast_ref::<HttpError>() {
  84                                         Some(http_error) => match JsonResponse::try_from(http_error.contents.clone()) {
  85                                                 Ok(JsonResponse(response)) => response,
  86                                                 Err(_) => Err(e)?,
  87                                         },
  88                                         None => Err(e)?,
  89                                 }
  90                         },
  91                         Err(e) => Err(e)?,
  92                 };
  93
  94                 if !response.is_object() {
  95                         return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "expected JSON object"));
  96                 }
  97
  98                 let error = &response["error"];
  99                 if !error.is_null() {
 100                         // TODO: Examine error code for a more precise std::io::ErrorKind.
 101                         let rpc_error = RpcError {
 102                                 code: error["code"].as_i64().unwrap_or(-1),
 103                                 message: error["message"].as_str().unwrap_or("unknown error").to_string()
 104                         };
 105                         return Err(std::io::Error::new(std::io::ErrorKind::Other, rpc_error));
 106                 }
 107
 108                 let result = &mut response["result"];
 109                 if result.is_null() {
 110                         return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "expected JSON result"));
 111                 }
 112
 113                 JsonResponse(result.take()).try_into()
 114         }
 115 }
 116
 117 impl BlockSource for RpcClient {
 118         fn get_header<'a>(&'a self, header_hash: &'a BlockHash, _height: Option<u32>) -> AsyncBlockSourceResult<'a, BlockHeaderData> {
 119                 Box::pin(async move {
 120                         let header_hash = serde_json::json!(header_hash.to_hex());
 121                         Ok(self.call_method("getblockheader", &[header_hash]).await?)
 122                 })
 123         }
 124
 125         fn get_block<'a>(&'a self, header_hash: &'a BlockHash) -> AsyncBlockSourceResult<'a, BlockData> {
 126                 Box::pin(async move {
 127                         let header_hash = serde_json::json!(header_hash.to_hex());
 128                         let verbosity = serde_json::json!(0);
 129                         Ok(BlockData::FullBlock(self.call_method("getblock", &[header_hash, verbosity]).await?))
 130                 })
 131         }
 132
 133         fn get_best_block<'a>(&'a self) -> AsyncBlockSourceResult<'a, (BlockHash, Option<u32>)> {
 134                 Box::pin(async move {
 135                         Ok(self.call_method("getblockchaininfo", &[]).await?)
 136                 })
 137         }
 138 }
 139
 140 #[cfg(test)]
 141 mod tests {
 142         use super::*;
 143         use crate::http::client_tests::{HttpServer, MessageBody};
 144
 145         /// Credentials encoded in base64.
 146         const CREDENTIALS: &'static str = "dXNlcjpwYXNzd29yZA==";
 147
 148         /// Converts a JSON value into `u64`.
 149         impl TryInto<u64> for JsonResponse {
 150                 type Error = std::io::Error;
 151
 152                 fn try_into(self) -> std::io::Result<u64> {
 153                         match self.0.as_u64() {
 154                                 None => Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "not a number")),
 155                                 Some(n) => Ok(n),
 156                         }
 157                 }
 158         }
 159
 160         #[tokio::test]
 161         async fn call_method_returning_unknown_response() {
 162                 let server = HttpServer::responding_with_not_found();
 163                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 164
 165                 match client.call_method::<u64>("getblockcount", &[]).await {
 166                         Err(e) => assert_eq!(e.kind(), std::io::ErrorKind::Other),
 167                         Ok(_) => panic!("Expected error"),
 168                 }
 169         }
 170
 171         #[tokio::test]
 172         async fn call_method_returning_malfomred_response() {
 173                 let response = serde_json::json!("foo");
 174                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 175                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 176
 177                 match client.call_method::<u64>("getblockcount", &[]).await {
 178                         Err(e) => {
 179                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 180                                 assert_eq!(e.get_ref().unwrap().to_string(), "expected JSON object");
 181                         },
 182                         Ok(_) => panic!("Expected error"),
 183                 }
 184         }
 185
 186         #[tokio::test]
 187         async fn call_method_returning_error() {
 188                 let response = serde_json::json!({
 189                         "error": { "code": -8, "message": "invalid parameter" },
 190                 });
 191                 let server = HttpServer::responding_with_server_error(response);
 192                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 193
 194                 let invalid_block_hash = serde_json::json!("foo");
 195                 match client.call_method::<u64>("getblock", &[invalid_block_hash]).await {
 196                         Err(e) => {
 197                                 assert_eq!(e.kind(), std::io::ErrorKind::Other);
 198                                 let rpc_error: Box<RpcError> = e.into_inner().unwrap().downcast().unwrap();
 199                                 assert_eq!(rpc_error.code, -8);
 200                                 assert_eq!(rpc_error.message, "invalid parameter");
 201                         },
 202                         Ok(_) => panic!("Expected error"),
 203                 }
 204         }
 205
 206         #[tokio::test]
 207         async fn call_method_returning_missing_result() {
 208                 let response = serde_json::json!({ "result": null });
 209                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 210                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 211
 212                 match client.call_method::<u64>("getblockcount", &[]).await {
 213                         Err(e) => {
 214                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 215                                 assert_eq!(e.get_ref().unwrap().to_string(), "expected JSON result");
 216                         },
 217                         Ok(_) => panic!("Expected error"),
 218                 }
 219         }
 220
 221         #[tokio::test]
 222         async fn call_method_returning_malformed_result() {
 223                 let response = serde_json::json!({ "result": "foo" });
 224                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 225                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 226
 227                 match client.call_method::<u64>("getblockcount", &[]).await {
 228                         Err(e) => {
 229                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 230                                 assert_eq!(e.get_ref().unwrap().to_string(), "not a number");
 231                         },
 232                         Ok(_) => panic!("Expected error"),
 233                 }
 234         }
 235
 236         #[tokio::test]
 237         async fn call_method_returning_valid_result() {
 238                 let response = serde_json::json!({ "result": 654470 });
 239                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 240                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 241
 242                 match client.call_method::<u64>("getblockcount", &[]).await {
 243                         Err(e) => panic!("Unexpected error: {:?}", e),
 244                         Ok(count) => assert_eq!(count, 654470),
 245                 }
 246         }
 247 }