Add /txs/package endpoint to submit tx packages

src/daemon.rs

@@ -128,6 +128,34 @@ struct NetworkInfo {
     relayfee: f64, // in BTC/kB
 }
 
+#[derive(Serialize, Deserialize, Debug)]
+struct MempoolFeesSubmitPackage {
+    base: f64,
+    #[serde(rename = "effective-feerate")]
+    effective_feerate: Option<f64>,
+    #[serde(rename = "effective-includes")]
+    effective_includes: Option<Vec<String>>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct SubmitPackageResult {
+    package_msg: String,
+    #[serde(rename = "tx-results")]
+    tx_results: HashMap<String, TxResult>,
+    #[serde(rename = "replaced-transactions")]
+    replaced_transactions: Option<Vec<String>>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct TxResult {
+    txid: String,
+    #[serde(rename = "other-wtxid")]
+    other_wtxid: Option<String>,
+    vsize: Option<u32>,
+    fees: Option<MempoolFeesSubmitPackage>,
+    error: Option<String>,
+}
+
 pub trait CookieGetter: Send + Sync {
     fn get(&self) -> Result<Vec<u8>>;
 }
@@ -549,6 +577,25 @@ impl Daemon {
         )
     }
 
+    pub fn submit_package(
+        &self,
+        txhex: Vec<String>,
+        maxfeerate: Option<f64>,
+        maxburnamount: Option<f64>,
+    ) -> Result<SubmitPackageResult> {
+        let params = match (maxfeerate, maxburnamount) {
+            (Some(rate), Some(burn)) => {
+                json!([txhex, format!("{:.8}", rate), format!("{:.8}", burn)])
+            }
+            (Some(rate), None) => json!([txhex, format!("{:.8}", rate)]),
+            (None, Some(burn)) => json!([txhex, null, format!("{:.8}", burn)]),
+            (None, None) => json!([txhex]),
+        };
+        let result = self.request("submitpackage", params)?;
+        serde_json::from_value::<SubmitPackageResult>(result)
+            .chain_err(|| "invalid submitpackage reply")
+    }
+
     // Get estimated feerates for the provided confirmation targets using a batch RPC request
     // Missing estimates are logged but do not cause a failure, whatever is available is returned
     #[allow(clippy::float_cmp)]

src/new_index/query.rs

@@ -6,7 +6,7 @@ use std::time::{Duration, Instant};
 
 use crate::chain::{Network, OutPoint, Transaction, TxOut, Txid};
 use crate::config::Config;
-use crate::daemon::Daemon;
+use crate::daemon::{Daemon, SubmitPackageResult};
 use crate::errors::*;
 use crate::new_index::{ChainQuery, Mempool, ScriptStats, SpendingInput, Utxo};
 use crate::util::{is_spendable, BlockId, Bytes, TransactionStatus};
@@ -78,6 +78,15 @@ impl Query {
         Ok(txid)
     }
 
+    pub fn submit_package(
+        &self,
+        txhex: Vec<String>,
+        maxfeerate: Option<f64>,
+        maxburnamount: Option<f64>,
+    ) -> Result<SubmitPackageResult> {
+        self.daemon.submit_package(txhex, maxfeerate, maxburnamount)
+    }
+
     pub fn utxo(&self, scripthash: &[u8]) -> Result<Vec<Utxo>> {
         let mut utxos = self.chain.utxo(scripthash, self.config.utxos_limit)?;
         let mempool = self.mempool();

src/rest.rs

@@ -15,7 +15,7 @@ use crate::util::{
 use bitcoin::consensus::encode;
 
 use bitcoin::hashes::FromSliceError as HashError;
-use hex::{DisplayHex, FromHex};
+use hex::{DisplayHex, FromHex, HexToBytesIter};
 use hyper::service::{make_service_fn, service_fn};
 use hyper::{Body, Method, Response, Server, StatusCode};
 use hyperlocal::UnixServerExt;
@@ -992,6 +992,58 @@ fn handle_request(
                 .map_err(|err| HttpError::from(err.description().to_string()))?;
             http_message(StatusCode::OK, txid.to_string(), 0)
         }
+        (&Method::POST, Some(&"txs"), Some(&"package"), None, None, None) => {
+            let txhexes: Vec<String> =
+                serde_json::from_str(String::from_utf8(body.to_vec())?.as_str())?;
+
+            if txhexes.len() > 25 {
+                Result::Err(HttpError::from(
+                    "Exceeded maximum of 25 transactions".to_string(),
+                ))?
+            }
+
+            let maxfeerate = query_params
+                .get("maxfeerate")
+                .map(|s| {
+                    s.parse::<f64>()
+                        .map_err(|_| HttpError::from("Invalid maxfeerate".to_string()))
+                })
+                .transpose()?;
+
+            let maxburnamount = query_params
+                .get("maxburnamount")
+                .map(|s| {
+                    s.parse::<f64>()
+                        .map_err(|_| HttpError::from("Invalid maxburnamount".to_string()))
+                })
+                .transpose()?;
+
+            // pre-checks
+            txhexes.iter().enumerate().try_for_each(|(index, txhex)| {
+                // each transaction must be of reasonable size
+                // (more than 60 bytes, within 400kWU standardness limit)
+                if !(120..800_000).contains(&txhex.len()) {
+                    Result::Err(HttpError::from(format!(
+                        "Invalid transaction size for item {}",
+                        index
+                    )))
+                } else {
+                    // must be a valid hex string
+                    HexToBytesIter::new(txhex)
+                        .and_then(|iter| iter.filter(|r| r.is_err()).next().transpose())
+                        .map_err(|_| {
+                            HttpError::from(format!("Invalid transaction hex for item {}", index))
+                        })
+                        .map(|_| ())
+                }
+            })?;
+
+            let result = query
+                .submit_package(txhexes, maxfeerate, maxburnamount)
+                .map_err(|err| HttpError::from(err.description().to_string()))?;
+
+            json_response(result, TTL_SHORT)
+        }
 
         (&Method::GET, Some(&"mempool"), None, None, None, None) => {
             json_response(query.mempool().backlog_stats(), TTL_SHORT)