feat: add metamask support (#2)

* add eth_getBlockByNumber and net_version

* fmt

client/src/client.rs

@@ -1,18 +1,22 @@
+use std::collections::HashMap;
 use std::sync::Arc;
 
 use ethers::prelude::{Address, U256};
 use eyre::Result;
 
 use config::Config;
-use consensus::types::Header;
+use consensus::types::{ExecutionPayload, Header};
 use consensus::ConsensusClient;
 use execution::evm::Evm;
+use execution::types::ExecutionBlock;
 use execution::ExecutionClient;
 
 pub struct Client {
     consensus: ConsensusClient,
     execution: ExecutionClient,
     config: Arc<Config>,
+    payloads: HashMap<u64, ExecutionPayload>,
+    block_head: u64,
 }
 
 impl Client {
@@ -25,52 +29,82 @@ impl Client {
             ConsensusClient::new(consensus_rpc, checkpoint_hash, config.clone()).await?;
         let execution = ExecutionClient::new(execution_rpc);
 
+        let payloads = HashMap::new();
+
         Ok(Client {
             consensus,
             execution,
             config,
+            payloads,
+            block_head: 0,
         })
     }
 
     pub async fn sync(&mut self) -> Result<()> {
-        self.consensus.sync().await
+        self.consensus.sync().await?;
+
+        let head = self.consensus.get_head();
+        let payload = self
+            .consensus
+            .get_execution_payload(&Some(head.slot))
+            .await?;
+        self.block_head = payload.block_number;
+        self.payloads.insert(payload.block_number, payload);
+
+        Ok(())
     }
 
     pub async fn advance(&mut self) -> Result<()> {
-        self.consensus.advance().await
+        self.consensus.advance().await?;
+
+        let head = self.consensus.get_head();
+        let payload = self
+            .consensus
+            .get_execution_payload(&Some(head.slot))
+            .await?;
+        self.block_head = payload.block_number;
+        self.payloads.insert(payload.block_number, payload);
+
+        Ok(())
     }
 
-    pub async fn call(&self, to: &Address, calldata: &Vec<u8>, value: U256) -> Result<Vec<u8>> {
+    pub fn call(
-        let payload = self.consensus.get_execution_payload().await?;
+        &self,
+        to: &Address,
+        calldata: &Vec<u8>,
+        value: U256,
+        block: &Option<u64>,
+    ) -> Result<Vec<u8>> {
+        let payload = self.get_payload(block)?;
         let mut evm = Evm::new(self.execution.clone(), payload);
         evm.call(to, calldata, value)
     }
 
-    pub async fn estimate_gas(&self, to: &Address, calldata: &Vec<u8>, value: U256) -> Result<u64> {
+    pub fn estimate_gas(&self, to: &Address, calldata: &Vec<u8>, value: U256) -> Result<u64> {
-        let payload = self.consensus.get_execution_payload().await?;
+        let payload = self.get_payload(&None)?;
         let mut evm = Evm::new(self.execution.clone(), payload);
         evm.estimate_gas(to, calldata, value)
     }
 
-    pub async fn get_balance(&self, address: &Address) -> Result<U256> {
+    pub async fn get_balance(&self, address: &Address, block: &Option<u64>) -> Result<U256> {
-        let payload = self.consensus.get_execution_payload().await?;
+        let payload = self.get_payload(block)?;
         let account = self.execution.get_account(&address, None, &payload).await?;
         Ok(account.balance)
     }
 
-    pub async fn get_nonce(&self, address: &Address) -> Result<U256> {
+    pub async fn get_nonce(&self, address: &Address, block: &Option<u64>) -> Result<U256> {
-        let payload = self.consensus.get_execution_payload().await?;
+        let payload = self.get_payload(block)?;
         let account = self.execution.get_account(&address, None, &payload).await?;
         Ok(account.nonce)
     }
 
-    pub async fn get_code(&self, address: &Address) -> Result<Vec<u8>> {
+    pub async fn get_code(&self, address: &Address, block: &Option<u64>) -> Result<Vec<u8>> {
-        let payload = self.consensus.get_execution_payload().await?;
+        let payload = self.get_payload(block)?;
         self.execution.get_code(&address, &payload).await
     }
 
     pub async fn get_storage_at(&self, address: &Address, slot: U256) -> Result<U256> {
-        let payload = self.consensus.get_execution_payload().await?;
+        let payload = self.get_payload(&None)?;
         let account = self
             .execution
             .get_account(address, Some(&[slot]), &payload)
@@ -82,23 +116,28 @@ impl Client {
         }
     }
 
-    pub async fn get_gas_price(&self) -> Result<U256> {
+    pub fn get_gas_price(&self) -> Result<U256> {
-        let payload = self.consensus.get_execution_payload().await?;
+        let payload = self.get_payload(&None)?;
         let base_fee = U256::from_little_endian(&payload.base_fee_per_gas.to_bytes_le());
         let tip = U256::from(10_u64.pow(9));
         Ok(base_fee + tip)
     }
 
-    pub async fn get_priority_fee(&self) -> Result<U256> {
+    pub fn get_priority_fee(&self) -> Result<U256> {
         let tip = U256::from(10_u64.pow(9));
         Ok(tip)
     }
 
-    pub async fn get_block_number(&self) -> Result<u64> {
+    pub fn get_block_number(&self) -> Result<u64> {
-        let payload = self.consensus.get_execution_payload().await?;
+        let payload = self.get_payload(&None)?;
         Ok(payload.block_number)
     }
 
+    pub fn get_block_by_number(&self, block: &Option<u64>) -> Result<ExecutionBlock> {
+        let payload = self.get_payload(block)?;
+        self.execution.get_block(&payload)
+    }
+
     pub fn chain_id(&self) -> u64 {
         self.config.general.chain_id
     }
@@ -106,4 +145,23 @@ impl Client {
     pub fn get_header(&self) -> &Header {
         self.consensus.get_head()
     }
+
+    fn get_payload(&self, block: &Option<u64>) -> Result<ExecutionPayload> {
+        match block {
+            Some(block) => {
+                let payload = self.payloads.get(block);
+                match payload {
+                    Some(payload) => Ok(payload.clone()),
+                    None => Err(eyre::eyre!("Block Not Found")),
+                }
+            }
+            None => {
+                let payload = self.payloads.get(&self.block_head);
+                match payload {
+                    Some(payload) => Ok(payload.clone()),
+                    None => Err(eyre::eyre!("Block Not Found")),
+                }
+            }
+        }
+    }
 }

client/src/rpc.rs

@@ -8,14 +8,14 @@ use std::{fmt::Display, net::SocketAddr, str::FromStr, sync::Arc};
 use tokio::sync::Mutex;
 
 use jsonrpsee::{
-    core::{async_trait, Error},
+    core::{async_trait, server::rpc_module::Methods, Error},
     http_server::{HttpServerBuilder, HttpServerHandle},
     proc_macros::rpc,
 };
 
-use common::utils::{hex_str_to_bytes, u64_to_hex_string};
-
 use super::Client;
+use common::utils::{hex_str_to_bytes, u64_to_hex_string};
+use execution::types::ExecutionBlock;
 
 pub struct Rpc {
     client: Arc<Mutex<Client>>,
@@ -63,8 +63,17 @@ trait EthRpc {
     async fn max_priority_fee_per_gas(&self) -> Result<String, Error>;
     #[method(name = "blockNumber")]
     async fn block_number(&self) -> Result<String, Error>;
+    #[method(name = "getBlockByNumber")]
+    async fn get_block_by_number(&self, num: &str, full_tx: bool) -> Result<ExecutionBlock, Error>;
 }
 
+#[rpc(client, server, namespace = "net")]
+trait NetRpc {
+    #[method(name = "version")]
+    async fn version(&self) -> Result<String, Error>;
+}
+
+#[derive(Clone)]
 struct RpcInner {
     client: Arc<Mutex<Client>>,
     port: u16,
@@ -73,60 +82,45 @@ struct RpcInner {
 #[async_trait]
 impl EthRpcServer for RpcInner {
     async fn get_balance(&self, address: &str, block: &str) -> Result<String, Error> {
-        match block {
+        let block = convert_err(decode_block(block))?;
-            "latest" => {
+        let address = convert_err(Address::from_str(address))?;
-                let address = convert_err(Address::from_str(address))?;
+        let client = self.client.lock().await;
-                let client = self.client.lock().await;
+        let balance = convert_err(client.get_balance(&address, &block).await)?;
-                let balance = convert_err(client.get_balance(&address).await)?;
 
-                Ok(balance.encode_hex())
+        Ok(balance.encode_hex())
-            }
-            _ => Err(Error::Custom("Invalid Block Number".to_string())),
-        }
     }
 
     async fn get_transaction_count(&self, address: &str, block: &str) -> Result<String, Error> {
-        match block {
+        let block = convert_err(decode_block(block))?;
-            "latest" => {
+        let address = convert_err(Address::from_str(address))?;
-                let address = convert_err(Address::from_str(address))?;
+        let client = self.client.lock().await;
-                let client = self.client.lock().await;
+        let nonce = convert_err(client.get_nonce(&address, &block).await)?;
-                let nonce = convert_err(client.get_nonce(&address).await)?;
 
-                Ok(nonce.encode_hex())
+        Ok(nonce.encode_hex())
-            }
-            _ => Err(Error::Custom("Invalid Block Number".to_string())),
-        }
     }
 
     async fn get_code(&self, address: &str, block: &str) -> Result<String, Error> {
-        match block {
+        let block = convert_err(decode_block(block))?;
-            "latest" => {
+        let address = convert_err(Address::from_str(address))?;
-                let address = convert_err(Address::from_str(address))?;
+        let client = self.client.lock().await;
-                let client = self.client.lock().await;
+        let code = convert_err(client.get_code(&address, &block).await)?;
-                let code = convert_err(client.get_code(&address).await)?;
 
-                Ok(hex::encode(code))
+        Ok(hex::encode(code))
-            }
-            _ => Err(Error::Custom("Invalid Block Number".to_string())),
-        }
     }
 
     async fn call(&self, opts: CallOpts, block: &str) -> Result<String, Error> {
-        match block {
+        let block = convert_err(decode_block(block))?;
-            "latest" => {
+        let to = convert_err(Address::from_str(&opts.to))?;
-                let to = convert_err(Address::from_str(&opts.to))?;
+        let data = convert_err(hex_str_to_bytes(&opts.data.unwrap_or("0x".to_string())))?;
-                let data = convert_err(hex_str_to_bytes(&opts.data.unwrap_or("0x".to_string())))?;
+        let value = convert_err(U256::from_str_radix(
-                let value = convert_err(U256::from_str_radix(
+            &opts.value.unwrap_or("0x0".to_string()),
-                    &opts.value.unwrap_or("0x0".to_string()),
+            16,
-                    16,
+        ))?;
-                ))?;
 
-                let client = self.client.lock().await;
+        let client = self.client.lock().await;
-                let res = convert_err(client.call(&to, &data, value).await)?;
+        let res = convert_err(client.call(&to, &data, value, &block))?;
-                Ok(hex::encode(res))
+
-            }
+        Ok(hex::encode(res))
-            _ => Err(Error::Custom("Invalid Block Number".to_string())),
-        }
     }
 
     async fn estimate_gas(&self, opts: CallOpts) -> Result<String, Error> {
@@ -138,7 +132,7 @@ impl EthRpcServer for RpcInner {
         ))?;
 
         let client = self.client.lock().await;
-        let gas = convert_err(client.estimate_gas(&to, &data, value).await)?;
+        let gas = convert_err(client.estimate_gas(&to, &data, value))?;
         Ok(u64_to_hex_string(gas))
     }
 
@@ -150,21 +144,41 @@ impl EthRpcServer for RpcInner {
 
     async fn gas_price(&self) -> Result<String, Error> {
         let client = self.client.lock().await;
-        let gas_price = convert_err(client.get_gas_price().await)?;
+        let gas_price = convert_err(client.get_gas_price())?;
         Ok(gas_price.encode_hex())
     }
 
     async fn max_priority_fee_per_gas(&self) -> Result<String, Error> {
         let client = self.client.lock().await;
-        let tip = convert_err(client.get_priority_fee().await)?;
+        let tip = convert_err(client.get_priority_fee())?;
         Ok(tip.encode_hex())
     }
 
     async fn block_number(&self) -> Result<String, Error> {
         let client = self.client.lock().await;
-        let num = convert_err(client.get_block_number().await)?;
+        let num = convert_err(client.get_block_number())?;
         Ok(u64_to_hex_string(num))
     }
+
+    async fn get_block_by_number(
+        &self,
+        block: &str,
+        _full_tx: bool,
+    ) -> Result<ExecutionBlock, Error> {
+        let block = convert_err(decode_block(block))?;
+        let client = self.client.lock().await;
+        let block = convert_err(client.get_block_by_number(&block))?;
+
+        Ok(block)
+    }
+}
+
+#[async_trait]
+impl NetRpcServer for RpcInner {
+    async fn version(&self) -> Result<String, Error> {
+        let client = self.client.lock().await;
+        Ok(client.chain_id().to_string())
+    }
 }
 
 async fn start(rpc: RpcInner) -> Result<(HttpServerHandle, SocketAddr)> {
@@ -172,13 +186,40 @@ async fn start(rpc: RpcInner) -> Result<(HttpServerHandle, SocketAddr)> {
     let server = HttpServerBuilder::default().build(addr).await?;
 
     let addr = server.local_addr()?;
-    let handle = server.start(rpc.into_rpc())?;
+
+    let mut methods = Methods::new();
+    let eth_methods: Methods = EthRpcServer::into_rpc(rpc.clone()).into();
+    let net_methods: Methods = NetRpcServer::into_rpc(rpc).into();
+
+    methods.merge(eth_methods)?;
+    methods.merge(net_methods)?;
+
+    let handle = server.start(methods)?;
 
     Ok((handle, addr))
 }
 
 fn convert_err<T, E: Display>(res: Result<T, E>) -> Result<T, Error> {
-    res.map_err(|err| Error::Custom(err.to_string()))
+    res.map_err(|err| {
+        println!("{}", err.to_string());
+        Error::Custom(err.to_string())
+    })
+}
+
+fn decode_block(block: &str) -> Result<Option<u64>> {
+    match block {
+        "latest" => Ok(None),
+        _ => {
+            if block.starts_with("0x") {
+                Ok(Some(u64::from_str_radix(
+                    block.strip_prefix("0x").unwrap(),
+                    16,
+                )?))
+            } else {
+                Ok(Some(block.parse()?))
+            }
+        }
+    }
 }
 
 #[derive(Deserialize, Serialize)]

consensus/src/consensus.rs

@@ -57,7 +57,7 @@ impl ConsensusClient {
             finalized_header: bootstrap.header.clone(),
             current_sync_committee: bootstrap.current_sync_committee,
             next_sync_committee: None,
-            optimistic_header: bootstrap.header,
+            optimistic_header: bootstrap.header.clone(),
             previous_max_active_participants: 0,
             current_max_active_participants: 0,
         };
@@ -65,8 +65,8 @@ impl ConsensusClient {
         Ok(ConsensusClient { rpc, store, config })
     }
 
-    pub async fn get_execution_payload(&self) -> Result<ExecutionPayload> {
+    pub async fn get_execution_payload(&self, slot: &Option<u64>) -> Result<ExecutionPayload> {
-        let slot = self.store.optimistic_header.slot;
+        let slot = slot.unwrap_or(self.store.optimistic_header.slot);
         let mut block = self.rpc.get_block(slot).await?.clone();
         let block_hash = block.hash_tree_root()?;
         let verified_block_hash = self.store.optimistic_header.clone().hash_tree_root()?;
@@ -319,6 +319,7 @@ impl ConsensusClient {
             && update.attested_header.slot > self.store.optimistic_header.slot
         {
             self.store.optimistic_header = update.attested_header.clone();
+
             println!(
                 "applying optimistic update for slot: {}",
                 self.store.optimistic_header.slot

consensus/src/types.rs

@@ -36,8 +36,7 @@ pub struct BeaconBlockBody {
     // TODO: handle
     attester_slashings: List<Dummy, 2>,
     attestations: List<Attestation, 128>,
-    // TODO: handle
+    deposits: List<Deposit, 16>,
-    deposits: List<Dummy, 16>,
     // TODO: handle
     voluntary_exits: List<Dummy, 16>,
     sync_aggregate: SyncAggregate,
@@ -47,33 +46,33 @@ pub struct BeaconBlockBody {
 #[derive(serde::Deserialize, Debug, Default, SimpleSerialize, Clone)]
 pub struct ExecutionPayload {
     #[serde(deserialize_with = "bytes32_deserialize")]
-    parent_hash: Bytes32,
+    pub parent_hash: Bytes32,
     #[serde(deserialize_with = "address_deserialize")]
-    fee_recipient: Address,
+    pub fee_recipient: Address,
     #[serde(deserialize_with = "bytes32_deserialize")]
     pub state_root: Bytes32,
     #[serde(deserialize_with = "bytes32_deserialize")]
     pub receipts_root: Bytes32,
     #[serde(deserialize_with = "logs_bloom_deserialize")]
-    logs_bloom: Vector<u8, 256>,
+    pub logs_bloom: Vector<u8, 256>,
     #[serde(deserialize_with = "bytes32_deserialize")]
-    prev_randao: Bytes32,
+    pub prev_randao: Bytes32,
     #[serde(deserialize_with = "u64_deserialize")]
     pub block_number: u64,
     #[serde(deserialize_with = "u64_deserialize")]
-    gas_limit: u64,
+    pub gas_limit: u64,
     #[serde(deserialize_with = "u64_deserialize")]
-    gas_used: u64,
+    pub gas_used: u64,
     #[serde(deserialize_with = "u64_deserialize")]
-    timestamp: u64,
+    pub timestamp: u64,
     #[serde(deserialize_with = "extra_data_deserialize")]
-    extra_data: List<u8, 32>,
+    pub extra_data: List<u8, 32>,
     #[serde(deserialize_with = "u256_deserialize")]
     pub base_fee_per_gas: U256,
     #[serde(deserialize_with = "bytes32_deserialize")]
     pub block_hash: Bytes32,
     #[serde(deserialize_with = "transactions_deserialize")]
-    transactions: List<Transaction, 1048576>,
+    pub transactions: List<Transaction, 1048576>,
 }
 
 #[derive(serde::Deserialize, Debug, Default, SimpleSerialize, Clone)]
@@ -109,6 +108,25 @@ struct Dummy {
     t: u64,
 }
 
+#[derive(serde::Deserialize, Debug, Default, SimpleSerialize, Clone)]
+struct Deposit {
+    #[serde(deserialize_with = "bytes_vector_deserialize")]
+    proof: Vector<Bytes32, 33>,
+    data: DepositData,
+}
+
+#[derive(serde::Deserialize, Default, Debug, SimpleSerialize, Clone)]
+struct DepositData {
+    #[serde(deserialize_with = "pubkey_deserialize")]
+    pubkey: BLSPubKey,
+    #[serde(deserialize_with = "bytes32_deserialize")]
+    withdrawal_credentials: Bytes32,
+    #[serde(deserialize_with = "u64_deserialize")]
+    amount: u64,
+    #[serde(deserialize_with = "signature_deserialize")]
+    signature: SignatureBytes,
+}
+
 #[derive(serde::Deserialize, Debug, Default, SimpleSerialize, Clone)]
 pub struct Eth1Data {
     #[serde(deserialize_with = "bytes32_deserialize")]
@@ -213,6 +231,21 @@ where
         .map_err(D::Error::custom)?)
 }
 
+fn bytes_vector_deserialize<'de, D>(deserializer: D) -> Result<Vector<Bytes32, 33>, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    let elems: Vec<String> = serde::Deserialize::deserialize(deserializer)?;
+    Ok(elems
+        .iter()
+        .map(|elem| {
+            let elem_bytes = hex_str_to_bytes(elem)?;
+            Ok(Vector::from_iter(elem_bytes))
+        })
+        .collect::<Result<Vector<Bytes32, 33>>>()
+        .map_err(D::Error::custom)?)
+}
+
 fn signature_deserialize<'de, D>(deserializer: D) -> Result<SignatureBytes, D::Error>
 where
     D: serde::Deserializer<'de>,

execution/src/execution.rs

@@ -1,7 +1,9 @@
 use std::collections::HashMap;
+use std::str::FromStr;
 
 use ethers::abi::AbiEncode;
 use ethers::prelude::{Address, U256};
+use ethers::types::H256;
 use ethers::utils::keccak256;
 use ethers::utils::rlp::encode;
 use eyre::Result;
@@ -11,7 +13,7 @@ use consensus::types::ExecutionPayload;
 
 use super::proof::{encode_account, verify_proof};
 use super::rpc::Rpc;
-use super::types::Account;
+use super::types::{Account, ExecutionBlock};
 
 #[derive(Clone)]
 pub struct ExecutionClient {
@@ -94,4 +96,39 @@ impl ExecutionClient {
 
         Ok(code)
     }
+
+    pub fn get_block(&self, payload: &ExecutionPayload) -> Result<ExecutionBlock> {
+        let empty_nonce = "0x0000000000000000".to_string();
+        let empty_uncle_hash = "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347";
+
+        let txs = payload
+            .transactions
+            .iter()
+            .map(|tx| H256::from_slice(&keccak256(tx.to_vec())))
+            .collect::<Vec<H256>>();
+
+        Ok(ExecutionBlock {
+            number: payload.block_number,
+            base_fee_per_gas: U256::from_little_endian(&payload.base_fee_per_gas.to_bytes_le()),
+            difficulty: U256::from(0),
+            extra_data: payload.extra_data.to_vec(),
+            gas_limit: payload.gas_limit,
+            gas_used: payload.gas_used,
+            hash: H256::from_slice(&payload.block_hash),
+            logs_bloom: payload.logs_bloom.to_vec(),
+            miner: Address::from_slice(&payload.fee_recipient),
+            parent_hash: H256::from_slice(&payload.parent_hash),
+            receipts_root: H256::from_slice(&payload.receipts_root),
+            state_root: H256::from_slice(&payload.state_root),
+            timestamp: payload.timestamp,
+            total_difficulty: 0,
+            transactions: txs,
+            mix_hash: H256::from_slice(&payload.prev_randao),
+            nonce: empty_nonce,
+            sha3_uncles: H256::from_str(empty_uncle_hash)?,
+            size: 0,
+            transactions_root: H256::default(),
+            uncles: vec![],
+        })
+    }
 }

execution/src/types.rs

@@ -3,9 +3,9 @@ use std::collections::HashMap;
 use ethers::prelude::{Address, H256, U256};
 use eyre::Result;
 use serde::de::Error;
-use serde::Deserialize;
+use serde::{Deserialize, Serialize};
 
-use common::utils::hex_str_to_bytes;
+use common::utils::{hex_str_to_bytes, u64_to_hex_string};
 
 #[derive(Deserialize, Debug)]
 #[serde(rename_all = "camelCase")]
@@ -38,6 +38,56 @@ pub struct Account {
     pub slots: HashMap<U256, U256>,
 }
 
+#[derive(Deserialize, Serialize, Debug)]
+#[serde(rename_all = "camelCase")]
+pub struct ExecutionBlock {
+    #[serde(serialize_with = "serialize_u64_string")]
+    pub number: u64,
+    pub base_fee_per_gas: U256,
+    pub difficulty: U256,
+    #[serde(serialize_with = "serialize_bytes")]
+    pub extra_data: Vec<u8>,
+    #[serde(serialize_with = "serialize_u64_string")]
+    pub gas_limit: u64,
+    #[serde(serialize_with = "serialize_u64_string")]
+    pub gas_used: u64,
+    pub hash: H256,
+    #[serde(serialize_with = "serialize_bytes")]
+    pub logs_bloom: Vec<u8>,
+    pub miner: Address,
+    pub mix_hash: H256,
+    pub nonce: String,
+    pub parent_hash: H256,
+    pub receipts_root: H256,
+    pub sha3_uncles: H256,
+    #[serde(serialize_with = "serialize_u64_string")]
+    pub size: u64,
+    pub state_root: H256,
+    #[serde(serialize_with = "serialize_u64_string")]
+    pub timestamp: u64,
+    #[serde(serialize_with = "serialize_u64_string")]
+    pub total_difficulty: u64,
+    pub transactions: Vec<H256>,
+    pub transactions_root: H256,
+    pub uncles: Vec<H256>,
+}
+
+fn serialize_bytes<S>(bytes: &Vec<u8>, s: S) -> Result<S::Ok, S::Error>
+where
+    S: serde::Serializer,
+{
+    let bytes_str = format!("0x{}", hex::encode(bytes));
+    s.serialize_str(&bytes_str)
+}
+
+fn serialize_u64_string<S>(x: &u64, s: S) -> Result<S::Ok, S::Error>
+where
+    S: serde::Serializer,
+{
+    let num_string = u64_to_hex_string(*x);
+    s.serialize_str(&num_string)
+}
+
 fn proof_deserialize<'de, D>(deserializer: D) -> Result<Vec<Vec<u8>>, D::Error>
 where
     D: serde::Deserializer<'de>,