feat: implement new RPC getrawbestchainlock

Author: knst

src/rpc/blockchain.cpp

@@ -269,6 +269,37 @@ static RPCHelpMan getbestchainlock()
     };
 }
 
+static RPCHelpMan getrawbestchainlock()
+{
+    return RPCHelpMan{"getrawbestchainlock",
+        "\nReturns the raw best ChainLock. Throws an error if there is no known ChainLock yet.",
+        {},
+        RPCResult{
+             RPCResult::Type::STR, "data", "The serialized, hex-encoded data for best ChainLock"
+        },
+        RPCExamples{
+            HelpExampleCli("getrawbestchainlock", "")
+            + HelpExampleRpc("getrawbestchainlock", "")
+        },
+    [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
+{
+    UniValue result(UniValue::VOBJ);
+
+    const NodeContext& node = EnsureAnyNodeContext(request.context);
+
+    LLMQContext& llmq_ctx = EnsureLLMQContext(node);
+    llmq::CChainLockSig clsig = llmq_ctx.clhandler->GetBestChainLock();
+    if (clsig.IsNull()) {
+        throw JSONRPCError(RPC_MISC_ERROR, "Unable to find any ChainLock");
+    }
+    CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
+    ssTx << clsig;
+    return HexStr(ssTx);
+
+},
+    };
+}
+
 void RPCNotifyBlockChange(const CBlockIndex* pindex)
 {
     if(pindex) {
@@ -2671,6 +2702,7 @@ static const CRPCCommand commands[] =
     { "blockchain",         &getblockstats,                      },
     { "blockchain",         &getbestblockhash,                   },
     { "blockchain",         &getbestchainlock,                   },
+    { "blockchain",         &getrawbestchainlock,                },
     { "blockchain",         &getblockcount,                      },
     { "blockchain",         &getblock,                           },
     { "blockchain",         &getblockfrompeer,                   },

test/functional/interface_zmq_dash.py

@@ -136,6 +136,8 @@ def run_test(self):
             self.zmq_context = zmq.Context()
             # Initialize the network
             self.nodes[0].sporkupdate("SPORK_17_QUORUM_DKG_ENABLED", 0)
+            self.log.info("Test RPC getrawbestchainlock before any CL appeared")
+            assert_raises_rpc_error(-1, "Unable to find any ChainLock", self.nodes[0].getrawbestchainlock)
             self.wait_for_sporks_same()
             self.activate_v19(expected_activation_height=900)
             self.log.info("Activated v19 at height:" + str(self.nodes[0].getblockcount()))
@@ -263,6 +265,7 @@ def test_chainlock_publishers(self):
         assert_equal(uint256_to_string(zmq_chain_lock.blockHash), rpc_chain_lock_hash)
         assert_equal(zmq_chain_locked_block.hash, rpc_chain_lock_hash)
         assert_equal(zmq_chain_lock.sig.hex(), rpc_best_chain_lock_sig)
+        assert_equal(zmq_chain_lock.serialize().hex(), self.nodes[0].getrawbestchainlock())
         # Unsubscribe from ChainLock messages
         self.unsubscribe(chain_lock_publishers)