feat: Add get_proof RPC (#205)

bus-mapping/src/eth_types.rs

@@ -4,8 +4,8 @@ use crate::evm::{memory::Memory, stack::Stack, storage::Storage};
 use crate::evm::{Gas, GasCost, OpcodeId, ProgramCounter};
 use ethers_core::types;
 pub use ethers_core::types::{
-    transaction::response::Transaction, Address, Block, Bytes, H160, H256,
-    U256, U64,
+    transaction::response::Transaction, Address, Block, Bytes,
+    EIP1186ProofResponse, H160, H256, U256, U64,
 };
 use pairing::arithmetic::FieldExt;
 use serde::{de, Deserialize};

bus-mapping/src/rpc.rs

@@ -2,7 +2,8 @@
 //! query a Geth node in order to get a Block, Tx or Trace info.
 
 use crate::eth_types::{
-    Block, GethExecTrace, Hash, ResultGethExecTraces, Transaction, U64,
+    Address, Block, EIP1186ProofResponse, GethExecTrace, Hash,
+    ResultGethExecTraces, Transaction, Word, U64,
 };
 use crate::Error;
 use ethers_providers::JsonRpcClient;
@@ -119,6 +120,24 @@ impl<P: JsonRpcClient> GethClient<P> {
             .map_err(|e| Error::JSONRpcError(e.into()))?;
         Ok(resp.0.into_iter().map(|step| step.result).collect())
     }
+
+    /// Calls `eth_getProof` via JSON-RPC returning a [`EIP1186ProofResponse`]
+    /// returning the account and storage-values of the specified
+    /// account including the Merkle-proof.
+    pub async fn get_proof(
+        &self,
+        account: Address,
+        keys: Vec<Word>,
+        block_num: BlockNumber,
+    ) -> Result<EIP1186ProofResponse, Error> {
+        let account = serialize(&account);
+        let keys = serialize(&keys);
+        let num = block_num.serialize();
+        self.0
+            .request("eth_getProof", [account, keys, num])
+            .await
+            .map_err(|e| Error::JSONRpcError(e.into()))
+    }
 }
 
 #[cfg(test)]
@@ -199,4 +218,44 @@ mod rpc_tests {
         );
         assert!(!trace_by_hash[0].struct_logs.is_empty());
     }
+
+    // The test is ignored as the values used depend on the Geth instance used
+    // each time you run the tests. And we can't assume that everyone will
+    // have a Geth client synced with mainnet to have unified "test-vectors".
+    #[ignore]
+    #[tokio::test]
+    async fn test_get_proof() {
+        let transport = Http::new(Url::parse("http://localhost:8545").unwrap());
+        let prov = GethClient::new(transport);
+
+        let address =
+            Address::from_str("0x7F0d15C7FAae65896648C8273B6d7E43f58Fa842")
+                .unwrap();
+        let keys = vec![Word::from_str("0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421").unwrap()];
+        let proof = prov
+            .get_proof(address, keys, BlockNumber::Latest)
+            .await
+            .unwrap();
+        const TARGET_PROOF: &str = r#"{
+            "address": "0x7f0d15c7faae65896648c8273b6d7e43f58fa842",
+            "accountProof": [
+                "0xf873a12050fb4d3174ec89ef969c09fd4391602169760fb005ad516f5d172cbffb80e955b84ff84d8089056bc75e2d63100000a056e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421a0c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470"
+            ],
+            "balance": "0x0",
+            "codeHash": "0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470",
+            "nonce": "0x0",
+            "storageHash": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+            "storageProof": [
+                {
+                    "key": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+                    "value": "0x0",
+                    "proof": []
+                }
+            ]
+        }"#;
+        assert!(
+            serde_json::from_str::<EIP1186ProofResponse>(TARGET_PROOF).unwrap()
+                == proof
+        );
+    }
 }