_ 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, 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 = self.client.post::<JsonResponse>(&uri, &host, &self.basic_auth, content)
  51                         .await?.0;
  52                 if !response.is_object() {
  53                         return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "expected JSON object"));
  54                 }
  55
  56                 let error = &response["error"];
  57                 if !error.is_null() {
  58                         // TODO: Examine error code for a more precise std::io::ErrorKind.
  59                         let message = error["message"].as_str().unwrap_or("unknown error");
  60                         return Err(std::io::Error::new(std::io::ErrorKind::Other, message));
  61                 }
  62
  63                 let result = &mut response["result"];
  64                 if result.is_null() {
  65                         return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "expected JSON result"));
  66                 }
  67
  68                 JsonResponse(result.take()).try_into()
  69         }
  70 }
  71
  72 impl BlockSource for RpcClient {
  73         fn get_header<'a>(&'a mut self, header_hash: &'a BlockHash, _height: Option<u32>) -> AsyncBlockSourceResult<'a, BlockHeaderData> {
  74                 Box::pin(async move {
  75                         let header_hash = serde_json::json!(header_hash.to_hex());
  76                         Ok(self.call_method("getblockheader", &[header_hash]).await?)
  77                 })
  78         }
  79
  80         fn get_block<'a>(&'a mut self, header_hash: &'a BlockHash) -> AsyncBlockSourceResult<'a, Block> {
  81                 Box::pin(async move {
  82                         let header_hash = serde_json::json!(header_hash.to_hex());
  83                         let verbosity = serde_json::json!(0);
  84                         Ok(self.call_method("getblock", &[header_hash, verbosity]).await?)
  85                 })
  86         }
  87
  88         fn get_best_block<'a>(&'a mut self) -> AsyncBlockSourceResult<'a, (BlockHash, Option<u32>)> {
  89                 Box::pin(async move {
  90                         Ok(self.call_method("getblockchaininfo", &[]).await?)
  91                 })
  92         }
  93 }
  94
  95 #[cfg(test)]
  96 mod tests {
  97         use super::*;
  98         use crate::http::client_tests::{HttpServer, MessageBody};
  99
 100         /// Credentials encoded in base64.
 101         const CREDENTIALS: &'static str = "dXNlcjpwYXNzd29yZA==";
 102
 103         /// Converts a JSON value into `u64`.
 104         impl TryInto<u64> for JsonResponse {
 105                 type Error = std::io::Error;
 106
 107                 fn try_into(self) -> std::io::Result<u64> {
 108                         match self.0.as_u64() {
 109                                 None => Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "not a number")),
 110                                 Some(n) => Ok(n),
 111                         }
 112                 }
 113         }
 114
 115         #[tokio::test]
 116         async fn call_method_returning_unknown_response() {
 117                 let server = HttpServer::responding_with_not_found();
 118                 let mut client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 119
 120                 match client.call_method::<u64>("getblockcount", &[]).await {
 121                         Err(e) => assert_eq!(e.kind(), std::io::ErrorKind::NotFound),
 122                         Ok(_) => panic!("Expected error"),
 123                 }
 124         }
 125
 126         #[tokio::test]
 127         async fn call_method_returning_malfomred_response() {
 128                 let response = serde_json::json!("foo");
 129                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 130                 let mut client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 131
 132                 match client.call_method::<u64>("getblockcount", &[]).await {
 133                         Err(e) => {
 134                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 135                                 assert_eq!(e.get_ref().unwrap().to_string(), "expected JSON object");
 136                         },
 137                         Ok(_) => panic!("Expected error"),
 138                 }
 139         }
 140
 141         #[tokio::test]
 142         async fn call_method_returning_error() {
 143                 let response = serde_json::json!({
 144                         "error": { "code": -8, "message": "invalid parameter" },
 145                 });
 146                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 147                 let mut client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 148
 149                 let invalid_block_hash = serde_json::json!("foo");
 150                 match client.call_method::<u64>("getblock", &[invalid_block_hash]).await {
 151                         Err(e) => {
 152                                 assert_eq!(e.kind(), std::io::ErrorKind::Other);
 153                                 assert_eq!(e.get_ref().unwrap().to_string(), "invalid parameter");
 154                         },
 155                         Ok(_) => panic!("Expected error"),
 156                 }
 157         }
 158
 159         #[tokio::test]
 160         async fn call_method_returning_missing_result() {
 161                 let response = serde_json::json!({ "result": null });
 162                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 163                 let mut client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 164
 165                 match client.call_method::<u64>("getblockcount", &[]).await {
 166                         Err(e) => {
 167                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 168                                 assert_eq!(e.get_ref().unwrap().to_string(), "expected JSON result");
 169                         },
 170                         Ok(_) => panic!("Expected error"),
 171                 }
 172         }
 173
 174         #[tokio::test]
 175         async fn call_method_returning_malformed_result() {
 176                 let response = serde_json::json!({ "result": "foo" });
 177                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 178                 let mut client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 179
 180                 match client.call_method::<u64>("getblockcount", &[]).await {
 181                         Err(e) => {
 182                                 assert_eq!(e.kind(), std::io::ErrorKind::InvalidData);
 183                                 assert_eq!(e.get_ref().unwrap().to_string(), "not a number");
 184                         },
 185                         Ok(_) => panic!("Expected error"),
 186                 }
 187         }
 188
 189         #[tokio::test]
 190         async fn call_method_returning_valid_result() {
 191                 let response = serde_json::json!({ "result": 654470 });
 192                 let server = HttpServer::responding_with_ok(MessageBody::Content(response));
 193                 let mut client = RpcClient::new(CREDENTIALS, server.endpoint()).unwrap();
 194
 195                 match client.call_method::<u64>("getblockcount", &[]).await {
 196                         Err(e) => panic!("Unexpected error: {:?}", e),
 197                         Ok(count) => assert_eq!(count, 654470),
 198                 }
 199         }
 200 }