_ 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 serde_json;
  11
  12 use std::convert::TryFrom;
  13 use std::convert::TryInto;
  14 use std::error::Error;
  15 use std::fmt;
  16 use std::sync::atomic::{AtomicUsize, Ordering};
  17
  18 /// An error returned by the RPC server.
  19 #[derive(Debug)]
  20 pub struct RpcError {
  21         /// The error code.
  22         pub code: i64,
  23         /// The error message.
  24         pub message: String,
  25 }
  26
  27 impl fmt::Display for RpcError {
  28     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  29         write!(f, "RPC error {}: {}", self.code, self.message)
  30     }
  31 }
  32
  33 impl Error for RpcError {}
  34
  35 /// A simple RPC client for calling methods using HTTP `POST`.
  36 ///
  37 /// Implements [`BlockSource`] and may return an `Err` containing [`RpcError`]. See
  38 /// [`RpcClient::call_method`] for details.
  39 pub struct RpcClient {
  40         basic_auth: String,
  41         endpoint: HttpEndpoint,
  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                 Ok(Self {
  51                         basic_auth: "Basic ".to_string() + credentials,
  52                         endpoint,
  53                         id: AtomicUsize::new(0),
  54                 })
  55         }
  56
  57         /// Calls a method with the response encoded in JSON format and interpreted as type `T`.
  58         ///
  59         /// When an `Err` is returned, [`std::io::Error::into_inner`] may contain an [`RpcError`] if
  60         /// [`std::io::Error::kind`] is [`std::io::ErrorKind::Other`].
  61         pub async fn call_method<T>(&self, method: &str, params: &[serde_json::Value]) -> std::io::Result<T>
  62         where JsonResponse: TryFrom<Vec<u8>, Error = std::io::Error> + TryInto<T, Error = std::io::Error> {
  63                 let host = format!("{}:{}", self.endpoint.host(), self.endpoint.port());
  64                 let uri = self.endpoint.path();
  65                 let content = serde_json::json!({
  66                         "method": method,
  67                         "params": params,
  68                         "id": &self.id.fetch_add(1, Ordering::AcqRel).to_string()
  69                 });
  70
  71                 let mut client = HttpClient::connect(&self.endpoint)?;
  72                 let mut response = match client.post::<JsonResponse>(&uri, &host, &self.basic_auth, content).await {
  73                         Ok(JsonResponse(response)) => response,
  74                         Err(e) if e.kind() == std::io::ErrorKind::Other => {
  75                                 match e.get_ref().unwrap().downcast_ref::<HttpError>() {
  76                                         Some(http_error) => match JsonResponse::try_from(http_error.contents.clone()) {
  77                                                 Ok(JsonResponse(response)) => response,
  78                                                 Err(_) => Err(e)?,
  79                                         },
  80                                         None => Err(e)?,
  81                                 }
  82                         },
  83                         Err(e) => Err(e)?,
  84                 };
  85
  86                 if !response.is_object() {
  87                         return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "expected JSON object"));
  88                 }
  89
  90                 let error = &response["error"];
  91                 if !error.is_null() {
  92                         // TODO: Examine error code for a more precise std::io::ErrorKind.
  93                         let rpc_error = RpcError {
  94                                 code: error["code"].as_i64().unwrap_or(-1),
  95                                 message: error["message"].as_str().unwrap_or("unknown error").to_string()
  96                         };
  97                         return Err(std::io::Error::new(std::io::ErrorKind::Other, rpc_error));
  98                 }
  99
 100                 let result = &mut response["result"];
 101                 if result.is_null() {
 102                         return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "expected JSON result"));
 103                 }
 104
 105                 JsonResponse(result.take()).try_into()
 106         }
 107 }
 108
 109 impl BlockSource for RpcClient {
 110         fn get_header<'a>(&'a self, header_hash: &'a BlockHash, _height: Option<u32>) -> AsyncBlockSourceResult<'a, BlockHeaderData> {
 111                 Box::pin(async move {
 112                         let header_hash = serde_json::json!(header_hash.to_hex());
 113                         Ok(self.call_method("getblockheader", &[header_hash]).await?)
 114                 })
 115         }
 116
 117         fn get_block<'a>(&'a self, header_hash: &'a BlockHash) -> AsyncBlockSourceResult<'a, BlockData> {
 118                 Box::pin(async move {
 119                         let header_hash = serde_json::json!(header_hash.to_hex());
 120                         let verbosity = serde_json::json!(0);
 121                         Ok(BlockData::FullBlock(self.call_method("getblock", &[header_hash, verbosity]).await?))
 122                 })
 123         }
 124
 125         fn get_best_block<'a>(&'a self) -> AsyncBlockSourceResult<'a, (BlockHash, Option<u32>)> {
 126                 Box::pin(async move {
 127                         Ok(self.call_method("getblockchaininfo", &[]).await?)
 128                 })
 129         }
 130 }
 131
 132 #[cfg(test)]
 133 mod tests {
 134         use super::*;
 135         use crate::http::client_tests::{HttpServer, MessageBody};
 136
 137         /// Credentials encoded in base64.
 138         const CREDENTIALS: &'static str = "dXNlcjpwYXNzd29yZA==";
 139
 140         /// Converts a JSON value into `u64`.
 141         impl TryInto<u64> for JsonResponse {
 142                 type Error = std::io::Error;
 143
 144                 fn try_into(self) -> std::io::Result<u64> {
 145                         match self.0.as_u64() {
 146                                 None => Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "not a number")),
 147                                 Some(n) => Ok(n),
 148                         }
 149                 }
 150         }
 151
 152         #[tokio::test]
 153         async fn call_method_returning_unknown_response() {
 154                 let server = HttpServer::responding_with_not_found();
 155                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 156
 157                 match client.call_method::<u64>("getblockcount", &[]).await {
 158                         Err(e) => assert_eq!(e.kind(), std::io::ErrorKind::Other),
 159                         Ok(_) => panic!("Expected error"),
 160                 }
 161         }
 162
 163         #[tokio::test]
 164         async fn call_method_returning_malfomred_response() {
 165                 let response = serde_json::json!("foo");
 166                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 167                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 168
 169                 match client.call_method::<u64>("getblockcount", &[]).await {
 170                         Err(e) => {
 171                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 172                                 assert_eq!(e.get_ref().unwrap().to_string(), "expected JSON object");
 173                         },
 174                         Ok(_) => panic!("Expected error"),
 175                 }
 176         }
 177
 178         #[tokio::test]
 179         async fn call_method_returning_error() {
 180                 let response = serde_json::json!({
 181                         "error": { "code": -8, "message": "invalid parameter" },
 182                 });
 183                 let server = HttpServer::responding_with_server_error(response);
 184                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 185
 186                 let invalid_block_hash = serde_json::json!("foo");
 187                 match client.call_method::<u64>("getblock", &[invalid_block_hash]).await {
 188                         Err(e) => {
 189                                 assert_eq!(e.kind(), std::io::ErrorKind::Other);
 190                                 let rpc_error: Box<RpcError> = e.into_inner().unwrap().downcast().unwrap();
 191                                 assert_eq!(rpc_error.code, -8);
 192                                 assert_eq!(rpc_error.message, "invalid parameter");
 193                         },
 194                         Ok(_) => panic!("Expected error"),
 195                 }
 196         }
 197
 198         #[tokio::test]
 199         async fn call_method_returning_missing_result() {
 200                 let response = serde_json::json!({ "result": null });
 201                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 202                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 203
 204                 match client.call_method::<u64>("getblockcount", &[]).await {
 205                         Err(e) => {
 206                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 207                                 assert_eq!(e.get_ref().unwrap().to_string(), "expected JSON result");
 208                         },
 209                         Ok(_) => panic!("Expected error"),
 210                 }
 211         }
 212
 213         #[tokio::test]
 214         async fn call_method_returning_malformed_result() {
 215                 let response = serde_json::json!({ "result": "foo" });
 216                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 217                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 218
 219                 match client.call_method::<u64>("getblockcount", &[]).await {
 220                         Err(e) => {
 221                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 222                                 assert_eq!(e.get_ref().unwrap().to_string(), "not a number");
 223                         },
 224                         Ok(_) => panic!("Expected error"),
 225                 }
 226         }
 227
 228         #[tokio::test]
 229         async fn call_method_returning_valid_result() {
 230                 let response = serde_json::json!({ "result": 654470 });
 231                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 232                 let client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 233
 234                 match client.call_method::<u64>("getblockcount", &[]).await {
 235                         Err(e) => panic!("Unexpected error: {:?}", e),
 236                         Ok(count) => assert_eq!(count, 654470),
 237                 }
 238         }
 239 }