Rename the coins folder to networks (#583)

* Rename the coins folder to networks

Ethereum isn't a coin. It's a network.

Resolves #357.

* More renames of coins -> networks in orchestration

* Correct paths in tests/

* cargo fmt

networks/bitcoin/src/rpc.rs

@@ -0,0 +1,226 @@
+use core::fmt::Debug;
+use std::collections::HashSet;
+
+use thiserror::Error;
+
+use serde::{Deserialize, de::DeserializeOwned};
+use serde_json::json;
+
+use simple_request::{hyper, Request, Client};
+
+use bitcoin::{
+  hashes::{Hash, hex::FromHex},
+  consensus::encode,
+  Txid, Transaction, BlockHash, Block,
+};
+
+#[derive(Clone, PartialEq, Eq, Debug, Deserialize)]
+pub struct Error {
+  code: isize,
+  message: String,
+}
+
+#[derive(Clone, Debug, Deserialize)]
+#[serde(untagged)]
+enum RpcResponse<T> {
+  Ok { result: T },
+  Err { error: Error },
+}
+
+/// A minimal asynchronous Bitcoin RPC client.
+#[derive(Clone, Debug)]
+pub struct Rpc {
+  client: Client,
+  url: String,
+}
+
+#[derive(Clone, PartialEq, Eq, Debug, Error)]
+pub enum RpcError {
+  #[error("couldn't connect to node")]
+  ConnectionError,
+  #[error("request had an error: {0:?}")]
+  RequestError(Error),
+  #[error("node replied with invalid JSON")]
+  InvalidJson(serde_json::error::Category),
+  #[error("node sent an invalid response ({0})")]
+  InvalidResponse(&'static str),
+  #[error("node was missing expected methods")]
+  MissingMethods(HashSet<&'static str>),
+}
+
+impl Rpc {
+  /// Create a new connection to a Bitcoin RPC.
+  ///
+  /// An RPC call is performed to ensure the node is reachable (and that an invalid URL wasn't
+  /// provided).
+  ///
+  /// Additionally, a set of expected methods is checked to be offered by the Bitcoin RPC. If these
+  /// methods aren't provided, an error with the missing methods is returned. This ensures all RPC
+  /// routes explicitly provided by this library are at least possible.
+  ///
+  /// Each individual RPC route may still fail at time-of-call, regardless of the arguments
+  /// provided to this library, if the RPC has an incompatible argument layout. That is not checked
+  /// at time of RPC creation.
+  pub async fn new(url: String) -> Result<Rpc, RpcError> {
+    let rpc = Rpc { client: Client::with_connection_pool(), url };
+
+    // Make an RPC request to verify the node is reachable and sane
+    let res: String = rpc.rpc_call("help", json!([])).await?;
+
+    // Verify all methods we expect are present
+    // If we had a more expanded RPC, due to differences in RPC versions, it wouldn't make sense to
+    // error if all methods weren't present
+    // We only provide a very minimal set of methods which have been largely consistent, hence why
+    // this is sane
+    let mut expected_methods = HashSet::from([
+      "help",
+      "getblockcount",
+      "getblockhash",
+      "getblockheader",
+      "getblock",
+      "sendrawtransaction",
+      "getrawtransaction",
+    ]);
+    for line in res.split('\n') {
+      // This doesn't check if the arguments are as expected
+      // This is due to Bitcoin supporting a large amount of optional arguments, which
+      // occasionally change, with their own mechanism of text documentation, making matching off
+      // it a quite involved task
+      // Instead, once we've confirmed the methods are present, we assume our arguments are aligned
+      // Else we'll error at time of call
+      if expected_methods.remove(line.split(' ').next().unwrap_or("")) &&
+        expected_methods.is_empty()
+      {
+        break;
+      }
+    }
+    if !expected_methods.is_empty() {
+      Err(RpcError::MissingMethods(expected_methods))?;
+    };
+
+    Ok(rpc)
+  }
+
+  /// Perform an arbitrary RPC call.
+  pub async fn rpc_call<Response: DeserializeOwned + Debug>(
+    &self,
+    method: &str,
+    params: serde_json::Value,
+  ) -> Result<Response, RpcError> {
+    let mut request = Request::from(
+      hyper::Request::post(&self.url)
+        .header("Content-Type", "application/json")
+        .body(
+          serde_json::to_vec(&json!({ "jsonrpc": "2.0", "method": method, "params": params }))
+            .unwrap()
+            .into(),
+        )
+        .unwrap(),
+    );
+    request.with_basic_auth();
+    let mut res = self
+      .client
+      .request(request)
+      .await
+      .map_err(|_| RpcError::ConnectionError)?
+      .body()
+      .await
+      .map_err(|_| RpcError::ConnectionError)?;
+
+    let res: RpcResponse<Response> =
+      serde_json::from_reader(&mut res).map_err(|e| RpcError::InvalidJson(e.classify()))?;
+    match res {
+      RpcResponse::Ok { result } => Ok(result),
+      RpcResponse::Err { error } => Err(RpcError::RequestError(error)),
+    }
+  }
+
+  /// Get the latest block's number.
+  ///
+  /// The genesis block's 'number' is zero. They increment from there.
+  pub async fn get_latest_block_number(&self) -> Result<usize, RpcError> {
+    // getblockcount doesn't return the amount of blocks on the current chain, yet the "height"
+    // of the current chain. The "height" of the current chain is defined as the "height" of the
+    // tip block of the current chain. The "height" of a block is defined as the amount of blocks
+    // present when the block was created. Accordingly, the genesis block has height 0, and
+    // getblockcount will return 0 when it's only the only block, despite their being one block.
+    self.rpc_call("getblockcount", json!([])).await
+  }
+
+  /// Get the hash of a block by the block's number.
+  pub async fn get_block_hash(&self, number: usize) -> Result<[u8; 32], RpcError> {
+    let mut hash = self
+      .rpc_call::<BlockHash>("getblockhash", json!([number]))
+      .await?
+      .as_raw_hash()
+      .to_byte_array();
+    // bitcoin stores the inner bytes in reverse order.
+    hash.reverse();
+    Ok(hash)
+  }
+
+  /// Get a block's number by its hash.
+  pub async fn get_block_number(&self, hash: &[u8; 32]) -> Result<usize, RpcError> {
+    #[derive(Deserialize, Debug)]
+    struct Number {
+      height: usize,
+    }
+    Ok(self.rpc_call::<Number>("getblockheader", json!([hex::encode(hash)])).await?.height)
+  }
+
+  /// Get a block by its hash.
+  pub async fn get_block(&self, hash: &[u8; 32]) -> Result<Block, RpcError> {
+    let hex = self.rpc_call::<String>("getblock", json!([hex::encode(hash), 0])).await?;
+    let bytes: Vec<u8> = FromHex::from_hex(&hex)
+      .map_err(|_| RpcError::InvalidResponse("node didn't use hex to encode the block"))?;
+    let block: Block = encode::deserialize(&bytes)
+      .map_err(|_| RpcError::InvalidResponse("node sent an improperly serialized block"))?;
+
+    let mut block_hash = *block.block_hash().as_raw_hash().as_byte_array();
+    block_hash.reverse();
+    if hash != &block_hash {
+      Err(RpcError::InvalidResponse("node replied with a different block"))?;
+    }
+
+    Ok(block)
+  }
+
+  /// Publish a transaction.
+  pub async fn send_raw_transaction(&self, tx: &Transaction) -> Result<Txid, RpcError> {
+    let txid = match self.rpc_call("sendrawtransaction", json!([encode::serialize_hex(tx)])).await {
+      Ok(txid) => txid,
+      Err(e) => {
+        // A const from Bitcoin's bitcoin/src/rpc/protocol.h
+        const RPC_VERIFY_ALREADY_IN_CHAIN: isize = -27;
+        // If this was already successfully published, consider this having succeeded
+        if let RpcError::RequestError(Error { code, .. }) = e {
+          if code == RPC_VERIFY_ALREADY_IN_CHAIN {
+            return Ok(tx.compute_txid());
+          }
+        }
+        Err(e)?
+      }
+    };
+    if txid != tx.compute_txid() {
+      Err(RpcError::InvalidResponse("returned TX ID inequals calculated TX ID"))?;
+    }
+    Ok(txid)
+  }
+
+  /// Get a transaction by its hash.
+  pub async fn get_transaction(&self, hash: &[u8; 32]) -> Result<Transaction, RpcError> {
+    let hex = self.rpc_call::<String>("getrawtransaction", json!([hex::encode(hash)])).await?;
+    let bytes: Vec<u8> = FromHex::from_hex(&hex)
+      .map_err(|_| RpcError::InvalidResponse("node didn't use hex to encode the transaction"))?;
+    let tx: Transaction = encode::deserialize(&bytes)
+      .map_err(|_| RpcError::InvalidResponse("node sent an improperly serialized transaction"))?;
+
+    let mut tx_hash = *tx.compute_txid().as_raw_hash().as_byte_array();
+    tx_hash.reverse();
+    if hash != &tx_hash {
+      Err(RpcError::InvalidResponse("node replied with a different transaction"))?;
+    }
+
+    Ok(tx)
+  }
+}