From aa495a624fe3de6364868a6dd08e14bb990e3c02 Mon Sep 17 00:00:00 2001
From: Joost Jager <joost.jager@gmail.com>
Date: Wed, 5 Feb 2025 11:55:15 +0100
Subject: [PATCH] Add pathfinding scores export method

The exported scores can be shared with light nodes and used to improve
pathfinding when only a limited local view on the network is available.
---
 bindings/ldk_node.udl |  2 ++
 src/lib.rs            | 19 +++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/bindings/ldk_node.udl b/bindings/ldk_node.udl
index be2befdba..632daa7df 100644
--- a/bindings/ldk_node.udl
+++ b/bindings/ldk_node.udl
@@ -126,6 +126,8 @@ interface Node {
 	NetworkGraph network_graph();
 	string sign_message([ByRef]sequence<u8> msg);
 	boolean verify_signature([ByRef]sequence<u8> msg, [ByRef]string sig, [ByRef]PublicKey pkey);
+	[Throws=NodeError]
+	bytes export_pathfinding_scores();
 };
 
 [Enum]
diff --git a/src/lib.rs b/src/lib.rs
index 793ab0d7f..2b292e3f6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1509,6 +1509,25 @@ impl Node {
 	pub fn verify_signature(&self, msg: &[u8], sig: &str, pkey: &PublicKey) -> bool {
 		self.keys_manager.verify_signature(msg, sig, pkey)
 	}
+
+	/// Exports the current state of the scorer. The result can be shared with and merged by light nodes that only have
+	/// a limited view of the network.
+	pub fn export_pathfinding_scores(&self) -> Result<Vec<u8>, Error> {
+		self.kv_store
+			.read(
+				lightning::util::persist::SCORER_PERSISTENCE_PRIMARY_NAMESPACE,
+				lightning::util::persist::SCORER_PERSISTENCE_SECONDARY_NAMESPACE,
+				lightning::util::persist::SCORER_PERSISTENCE_KEY,
+			)
+			.map_err(|e| {
+				log_error!(
+					self.logger,
+					"Failed to access store while exporting pathfinding scores: {}",
+					e
+				);
+				Error::PersistenceFailed
+			})
+	}
 }
 
 impl Drop for Node {