feat(rpc) Implement Filecoin.StateGetRandomnessDigestFromTickets (#4566)

CHANGELOG.md

@@ -66,6 +66,9 @@
 - [#4547](https://github.com/ChainSafe/forest/pull/4547) Add support for the
   `Filecoin.MpoolPushUntrusted` RPC method.
 
+- [#4566](https://github.com/ChainSafe/forest/pull/4566) Add support for the
+  `Filecoin.StateGetRandomnessDigestFromTickets` RPC method.
+
 ### Changed
 
 ### Removed

src/rpc/methods/state.rs

@@ -1384,6 +1384,28 @@ impl RpcMethod<4> for StateGetRandomnessFromTickets {
     }
 }
 
+pub enum StateGetRandomnessDigestFromTickets {}
+
+impl RpcMethod<2> for StateGetRandomnessDigestFromTickets {
+    const NAME: &'static str = "Filecoin.StateGetRandomnessDigestFromTickets";
+    const PARAM_NAMES: [&'static str; 2] = ["rand_epoch", "tipset_key"];
+    const API_PATHS: ApiPaths = ApiPaths::V1;
+    const PERMISSION: Permission = Permission::Read;
+
+    type Params = (ChainEpoch, ApiTipsetKey);
+    type Ok = Vec<u8>;
+
+    async fn handle(
+        ctx: Ctx<impl Blockstore>,
+        (rand_epoch, ApiTipsetKey(tsk)): Self::Params,
+    ) -> Result<Self::Ok, ServerError> {
+        let tipset = ctx.chain_store().load_required_tipset_or_heaviest(&tsk)?;
+        let chain_rand = ctx.state_manager.chain_rand(tipset);
+        let digest = chain_rand.get_chain_randomness(rand_epoch, false)?;
+        Ok(digest.to_vec())
+    }
+}
+
 /// Get randomness from beacon
 pub enum StateGetRandomnessFromBeacon {}
 

src/rpc/mod.rs

@@ -153,6 +153,7 @@ macro_rules! for_each_method {
         $callback!(crate::rpc::state::StateMinerInitialPledgeCollateral);
         $callback!(crate::rpc::state::StateGetReceipt);
         $callback!(crate::rpc::state::StateGetRandomnessFromTickets);
+        $callback!(crate::rpc::state::StateGetRandomnessDigestFromTickets);
         $callback!(crate::rpc::state::StateGetRandomnessFromBeacon);
         $callback!(crate::rpc::state::StateReadState);
         $callback!(crate::rpc::state::StateCirculatingSupply);

src/tool/subcommands/api_cmd.rs

@@ -704,6 +704,10 @@ fn state_tests_with_tipset<DB: Blockstore>(
             "dead beef".as_bytes().to_vec(),
             tipset.key().into(),
         ))?),
+        RpcTest::identity(StateGetRandomnessDigestFromTickets::request((
+            tipset.epoch(),
+            tipset.key().into(),
+        ))?),
         RpcTest::identity(StateGetRandomnessFromBeacon::request((
             DomainSeparationTag::ElectionProofProduction as i64,
             tipset.epoch(),