use crate::error::{Context, Error, ensure};
use crate::transaction::decode;
use crate::{endpoints::PublicEndpoint, esplora};
use bitcoin::{Amount, Block, BlockHash, Denomination, Txid, consensus::deserialize};
use serde_json::{Value, json};
use std::{
cell::Cell,
io::Read,
time::{Duration, Instant},
};
use urma_chain::{
observation::Chain,
validation::{BlockValidationError, validate_block_integrity},
};
pub(crate) struct Source {
endpoint: PublicEndpoint,
network: Cell<NetworkState>,
last_request: Cell<Instant>,
retry_at: Cell<Instant>,
window_start: Cell<Instant>,
window_requests: Cell<u8>,
}
#[derive(Clone, Copy)]
enum NetworkState {
Unchecked,
Verified,
Rejected,
}
impl Source {
pub(crate) fn new(endpoint: PublicEndpoint) -> Result<Self, Error> {
endpoint.validate()?;
Ok(Self {
endpoint,
network: Cell::new(NetworkState::Unchecked),
last_request: Cell::new(Instant::now()),
retry_at: Cell::new(Instant::now()),
window_start: Cell::new(Instant::now()),
window_requests: Cell::new(0),
})
}
pub(crate) fn call(&self, chain: Chain, method: &str, args: &[Value]) -> Result<Value, Error> {
ensure!(
Instant::now() >= self.retry_at.get(),
"public source cooling down after rate limit"
);
ensure!(
!matches!(self.network.get(), NetworkState::Rejected),
"public source network mismatch"
);
if matches!(self.network.get(), NetworkState::Unchecked) {
let genesis = self.request("getblockhash", &[json!(0)])?;
if genesis != json!(chain.genesis()?.0.to_string()) {
self.network.set(NetworkState::Rejected);
return Err(Error::Invalid("public source network mismatch".into()));
}
let tip = self.request("getblockchaininfo", &[])?;
validate_shape("getblockchaininfo", &tip)?;
ensure!(
tip["initialblockdownload"] == false,
"public source is still synchronizing"
);
self.network.set(NetworkState::Verified);
}
if method == "getblockhash" && args.first().context("missing block height")? == &json!(0) {
return Ok(json!(chain.genesis()?.0.to_string()));
}
let value = self.request(method, args)?;
validate_result(method, args, &value)?;
Ok(value)
}
fn request(&self, method: &str, args: &[Value]) -> Result<Value, Error> {
self.reserve_request()?;
pace(self.last_request.get());
self.last_request.set(Instant::now());
let result = self.request_unchecked(method, args);
match result {
Err(Error::Io(cause)) if cause.kind() == std::io::ErrorKind::WouldBlock => {
self.retry_at.set(Instant::now() + Duration::from_secs(60));
Err(Error::Io(cause))
}
Ok(value) => Ok(value),
Err(cause) => Err(cause),
}
}
fn reserve_request(&self) -> Result<(), Error> {
if self.endpoint.url().contains(".gateway.tatum.io") {
if self.window_start.get().elapsed() >= Duration::from_secs(60) {
self.window_start.set(Instant::now());
self.window_requests.set(0);
}
ensure!(
self.window_requests.get() < 5,
"public RPC minute budget exhausted"
);
self.window_requests.set(self.window_requests.get() + 1);
}
Ok(())
}
fn request_unchecked(&self, method: &str, args: &[Value]) -> Result<Value, Error> {
match &self.endpoint {
PublicEndpoint::Esplora(url) => esplora::call(url, method, args),
PublicEndpoint::Rpc(url) => {
let bytes = request(
minreq::post(url)
.with_header("Content-Type", "application/json")
.with_body(serde_json::to_vec(
&json!({"jsonrpc":"2.0","id":1,"method":method,"params":args}),
)?),
)?;
let response: Value = serde_json::from_slice(&bytes)?;
if !response["error"].is_null() {
if response["error"]["code"] == -5 {
return Err(Error::Missing(
"transaction not found on selected network".into(),
));
}
return Err(Error::Unsupported(format!(
"public RPC {method} failed (code {})",
response["error"]["code"]
)));
}
Ok(response
.get("result")
.context("public RPC omitted result")?
.clone())
}
}
}
}
pub(crate) fn request(request: minreq::Request) -> Result<Vec<u8>, Error> {
let request = request
.with_header("User-Agent", "urma/0.1")
.with_timeout(12)
.with_max_redirects(0);
let response = request.send_lazy()?;
if response.status_code == 429 {
return Err(Error::Io(std::io::Error::new(
std::io::ErrorKind::WouldBlock,
"public source rate limited; retry after one minute",
)));
}
if response.status_code == 404 {
return Err(Error::Missing(
"transaction or block not found on selected network".into(),
));
}
ensure!(
response.status_code == 200,
"public source returned HTTP {}",
response.status_code
);
let mut bytes = Vec::new();
Read::take(response, 32 * 1024 * 1024 + 1).read_to_end(&mut bytes)?;
ensure!(
bytes.len() <= 32 * 1024 * 1024,
"public response exceeds capacity"
);
Ok(bytes)
}
fn validate_result(method: &str, args: &[Value], value: &Value) -> Result<(), Error> {
validate_shape(method, value)?;
if method == "getrawtransaction"
&& args.get(1).context("missing transaction verbosity")? == &json!(true)
{
validate_confirmations(value)?;
}
if method == "getrawtransaction"
&& args.get(1).context("missing transaction verbosity")? == &json!(false)
{
let raw = value.as_str().context("missing transaction bytes")?;
let transaction = decode(raw, raw.len())?;
ensure!(
json!(transaction.compute_txid()) == *args.first().context("missing transaction ID")?,
"public source transaction hash mismatch"
);
}
if method == "sendrawtransaction" {
let raw = args.first().context("missing broadcast transaction")?;
let raw = raw.as_str().context("invalid broadcast transaction")?;
let transaction = decode(raw, raw.len())?;
ensure!(
value == &json!(transaction.compute_txid()),
"broadcast transaction ID mismatch"
);
}
if method == "getblock" {
let raw = hex::decode(value.as_str().context("missing block bytes")?)?;
let block: Block = deserialize(&raw)?;
let expected_hash = args
.first()
.context("missing block hash")?
.as_str()
.context("invalid block hash")?
.parse()?;
validate_block_integrity(&block, expected_hash).map_err(|cause| match cause {
BlockValidationError::HashMismatch => {
Error::Invalid("public source block hash mismatch".into())
}
BlockValidationError::MerkleRootMismatch => {
Error::Invalid("public source block merkle root mismatch".into())
}
cause => Error::from(cause),
})?;
}
Ok(())
}
fn block_hash(value: &Value) -> Result<(), Error> {
value
.as_str()
.context("missing public block hash")?
.parse::<BlockHash>()?;
Ok(())
}
fn validate_confirmations(value: &Value) -> Result<(), Error> {
let count = value["confirmations"]
.as_i64()
.context("invalid public confirmation count")?;
if count > 0 {
block_hash(&value["blockhash"])?;
}
Ok(())
}
fn validate_shape(method: &str, value: &Value) -> Result<(), Error> {
match method {
"getblockhash" => block_hash(value)?,
"getblockchaininfo" => {
value["blocks"]
.as_u64()
.context("invalid public chain height")?;
block_hash(&value["bestblockhash"])?;
ensure!(
value["initialblockdownload"] == false,
"public source is synchronizing or omitted synchronization state"
);
}
"getblockheader" => {
value["height"]
.as_u64()
.context("invalid public block height")?;
}
"getrawmempool" => {
let rows = value.as_array().context("invalid public mempool list")?;
ensure!(
rows.len() <= 1_000_000,
"public mempool response exceeds capacity"
);
for row in rows {
row.as_str()
.context("invalid public mempool txid")?
.parse::<Txid>()?;
}
}
"addressutxos" => validate_utxos(value)?,
"gettxout" => validate_output(value)?,
"testmempoolaccept" => {
let rows = value
.as_array()
.context("invalid public preflight result")?;
ensure!(rows.len() == 1, "invalid public preflight count");
rows[0]["allowed"]
.as_bool()
.context("missing public preflight decision")?;
}
_ => (),
}
Ok(())
}
fn validate_utxos(value: &Value) -> Result<(), Error> {
let rows = value.as_array().context("invalid public UTXO list")?;
ensure!(rows.len() <= 1000, "UTXO client capacity exceeded");
for row in rows {
row["txid"]
.as_str()
.context("missing public UTXO txid")?
.parse::<Txid>()?;
u32::try_from(row["vout"].as_u64().context("invalid public UTXO index")?)?;
row["value"].as_u64().context("invalid public UTXO value")?;
let confirmed = row["status"]["confirmed"]
.as_bool()
.context("invalid public UTXO status")?;
if confirmed {
row["status"]["block_height"]
.as_u64()
.context("invalid public UTXO height")?;
}
}
Ok(())
}
fn validate_output(value: &Value) -> Result<(), Error> {
if value.is_null() {
return Ok(());
}
value["confirmations"]
.as_u64()
.context("invalid public output confirmations")?;
value["coinbase"]
.as_bool()
.context("invalid public coinbase status")?;
Amount::from_str_in(&value["value"].to_string(), Denomination::Bitcoin)?;
let script = value["scriptPubKey"]["hex"]
.as_str()
.context("invalid public output script")?;
ensure!(
script.len() <= 20_000,
"public output script exceeds capacity"
);
hex::decode(script)?;
Ok(())
}
fn pace(last: Instant) {
let delay = match Duration::from_millis(300).checked_sub(last.elapsed()) {
Some(delay) => delay,
None => return,
};
std::thread::sleep(delay);
}