_ Git - rust-lightning/blob - lightning-block-sync/src/rest.rs

   1 //! Simple REST client implementation which implements [`BlockSource`] against a Bitcoin Core REST
   2 //! endpoint.
   3
   4 use crate::{BlockData, BlockHeaderData, BlockSource, AsyncBlockSourceResult};
   5 use crate::http::{BinaryResponse, HttpEndpoint, HttpClient, JsonResponse};
   6
   7 use bitcoin::hash_types::BlockHash;
   8 use bitcoin::hashes::hex::ToHex;
   9
  10 use std::convert::TryFrom;
  11 use std::convert::TryInto;
  12 use std::sync::Mutex;
  13
  14 /// A simple REST client for requesting resources using HTTP `GET`.
  15 pub struct RestClient {
  16         endpoint: HttpEndpoint,
  17         client: Mutex<Option<HttpClient>>,
  18 }
  19
  20 impl RestClient {
  21         /// Creates a new REST client connected to the given endpoint.
  22         ///
  23         /// The endpoint should contain the REST path component (e.g., http://127.0.0.1:8332/rest).
  24         pub fn new(endpoint: HttpEndpoint) -> std::io::Result<Self> {
  25                 Ok(Self { endpoint, client: Mutex::new(None) })
  26         }
  27
  28         /// Requests a resource encoded in `F` format and interpreted as type `T`.
  29         pub async fn request_resource<F, T>(&self, resource_path: &str) -> std::io::Result<T>
  30         where F: TryFrom<Vec<u8>, Error = std::io::Error> + TryInto<T, Error = std::io::Error> {
  31                 let host = format!("{}:{}", self.endpoint.host(), self.endpoint.port());
  32                 let uri = format!("{}/{}", self.endpoint.path().trim_end_matches("/"), resource_path);
  33                 let mut client = if let Some(client) = self.client.lock().unwrap().take() { client }
  34                         else { HttpClient::connect(&self.endpoint)? };
  35                 let res = client.get::<F>(&uri, &host).await?.try_into();
  36                 *self.client.lock().unwrap() = Some(client);
  37                 res
  38         }
  39 }
  40
  41 impl BlockSource for RestClient {
  42         fn get_header<'a>(&'a self, header_hash: &'a BlockHash, _height: Option<u32>) -> AsyncBlockSourceResult<'a, BlockHeaderData> {
  43                 Box::pin(async move {
  44                         let resource_path = format!("headers/1/{}.json", header_hash.to_hex());
  45                         Ok(self.request_resource::<JsonResponse, _>(&resource_path).await?)
  46                 })
  47         }
  48
  49         fn get_block<'a>(&'a self, header_hash: &'a BlockHash) -> AsyncBlockSourceResult<'a, BlockData> {
  50                 Box::pin(async move {
  51                         let resource_path = format!("block/{}.bin", header_hash.to_hex());
  52                         Ok(BlockData::FullBlock(self.request_resource::<BinaryResponse, _>(&resource_path).await?))
  53                 })
  54         }
  55
  56         fn get_best_block<'a>(&'a self) -> AsyncBlockSourceResult<'a, (BlockHash, Option<u32>)> {
  57                 Box::pin(async move {
  58                         Ok(self.request_resource::<JsonResponse, _>("chaininfo.json").await?)
  59                 })
  60         }
  61 }
  62
  63 #[cfg(test)]
  64 mod tests {
  65         use super::*;
  66         use crate::http::BinaryResponse;
  67         use crate::http::client_tests::{HttpServer, MessageBody};
  68
  69         /// Parses binary data as a string-encoded `u32`.
  70         impl TryInto<u32> for BinaryResponse {
  71                 type Error = std::io::Error;
  72
  73                 fn try_into(self) -> std::io::Result<u32> {
  74                         match std::str::from_utf8(&self.0) {
  75                                 Err(e) => Err(std::io::Error::new(std::io::ErrorKind::InvalidData, e)),
  76                                 Ok(s) => match u32::from_str_radix(s, 10) {
  77                                         Err(e) => Err(std::io::Error::new(std::io::ErrorKind::InvalidData, e)),
  78                                         Ok(n) => Ok(n),
  79                                 }
  80                         }
  81                 }
  82         }
  83
  84         #[tokio::test]
  85         async fn request_unknown_resource() {
  86                 let server = HttpServer::responding_with_not_found();
  87                 let client = RestClient::new(server.endpoint()).unwrap();
  88
  89                 match client.request_resource::<BinaryResponse, u32>("/").await {
  90                         Err(e) => assert_eq!(e.kind(), std::io::ErrorKind::Other),
  91                         Ok(_) => panic!("Expected error"),
  92                 }
  93         }
  94
  95         #[tokio::test]
  96         async fn request_malformed_resource() {
  97                 let server = HttpServer::responding_with_ok(MessageBody::Content("foo"));
  98                 let client = RestClient::new(server.endpoint()).unwrap();
  99
 100                 match client.request_resource::<BinaryResponse, u32>("/").await {
 101                         Err(e) => assert_eq!(e.kind(), std::io::ErrorKind::InvalidData),
 102                         Ok(_) => panic!("Expected error"),
 103                 }
 104         }
 105
 106         #[tokio::test]
 107         async fn request_valid_resource() {
 108                 let server = HttpServer::responding_with_ok(MessageBody::Content(42));
 109                 let client = RestClient::new(server.endpoint()).unwrap();
 110
 111                 match client.request_resource::<BinaryResponse, u32>("/").await {
 112                         Err(e) => panic!("Unexpected error: {:?}", e),
 113                         Ok(n) => assert_eq!(n, 42),
 114                 }
 115         }
 116 }