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