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