feat: Batch read methods requests (#10192)

* feat: Batch read methods requests

* Fix tests

* Process review comments

apps/block_scout_web/test/block_scout_web/controllers/api/v2/smart_contract_controller_test.exs

@@ -1677,23 +1677,33 @@ defmodule BlockScoutWeb.API.V2.SmartContractControllerTest do
 
       target_contract = insert(:smart_contract, abi: abi)
 
-      blockchain_eth_call_mock()
+      address_hash = to_string(target_contract.address_hash)
 
       expect(
         EthereumJSONRPC.Mox,
         :json_rpc,
         fn [
              %{
-               id: id,
+               id: id_1,
                method: "eth_call",
-               params: [%{to: _address_hash, from: "0xBb36c792B9B45Aaf8b848A1392B0d6559202729E"}, _]
+               params: [%{to: ^address_hash, from: "0xBb36c792B9B45Aaf8b848A1392B0d6559202729E", data: "0x2e64cec1"}, _]
+             },
+             %{
+               id: id_2,
+               method: "eth_call",
+               params: [%{to: ^address_hash, from: "0xBb36c792B9B45Aaf8b848A1392B0d6559202729E", data: "0xab470f05"}, _]
              }
            ],
            _opts ->
           {:ok,
            [
              %{
-               id: id,
+               id: id_2,
+               jsonrpc: "2.0",
+               result: "0x000000000000000000000000fffffffffffffffffffffffffffffffffffffffe"
+             },
+             %{
+               id: id_1,
                jsonrpc: "2.0",
                result:
                  "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"

apps/explorer/lib/explorer/smart_contract/reader.ex

@@ -291,9 +291,7 @@ defmodule Explorer.SmartContract.Reader do
 
     abi_with_method_id
     |> Enum.filter(&Helper.queriable_method?(&1))
-    |> Enum.map(
-      &fetch_current_value_from_blockchain(&1, abi_with_method_id, contract_address_hash, false, options, from)
-    )
+    |> fetch_current_values_from_blockchain(abi_with_method_id, contract_address_hash, false, options, from)
   end
 
   def read_only_functions_from_abi_with_sender(_, _, _, _), do: []
@@ -356,39 +354,88 @@ defmodule Explorer.SmartContract.Reader do
     "tuple[#{tuple_types}]"
   end
 
-  def fetch_current_value_from_blockchain(
-        function,
+  @spec fetch_current_values_from_blockchain(
+          any(),
+          [%{optional(binary()) => any()}],
+          Explorer.Chain.Hash.t(),
+          boolean(),
+          keyword(),
+          nil | binary()
+        ) :: [SmartContract.function_description()]
+  def fetch_current_values_from_blockchain(
+        functions,
         abi,
         contract_address_hash,
         leave_error_as_map,
         options,
         from \\ nil
       ) do
-    case function do
-      %{"inputs" => []} ->
-        method_id = function["method_id"]
-        args = function["inputs"]
-
-        %{output: outputs, names: names} =
-          query_function_with_names(
-            contract_address_hash,
-            %{method_id: method_id, args: args},
-            :regular,
-            from,
-            abi,
-            leave_error_as_map,
-            options
-          )
-
-        function
-        |> Map.replace!("outputs", outputs)
-        |> Map.put("abi_outputs", Map.get(function, "outputs", []))
-        |> Map.put("names", names)
+    initial_methods_id_order = Enum.map(functions, &Map.get(&1, "method_id"))
+
+    %{to_be_fetched: to_be_fetched, method_id_to_outputs: method_id_to_outputs, unchanged: unchanged} =
+      Enum.reduce(
+        functions,
+        %{to_be_fetched: %{}, method_id_to_outputs: %{}, unchanged: %{}},
+        fn function,
+           %{
+             to_be_fetched: to_be_fetched,
+             unchanged: unchanged,
+             method_id_to_outputs: method_id_to_outputs
+           } ->
+          case function do
+            %{"inputs" => []} ->
+              [%ABI.FunctionSelector{returns: returns, method_id: _method_id}] = ABI.parse_specification([function])
+
+              outputs = extract_outputs(returns)
+
+              %{
+                to_be_fetched: Map.put(to_be_fetched, function["method_id"], function),
+                unchanged: unchanged,
+                method_id_to_outputs: Map.put(method_id_to_outputs, function["method_id"], {outputs, function})
+              }
+
+            _ ->
+              %{
+                to_be_fetched: to_be_fetched,
+                unchanged:
+                  Map.put(
+                    unchanged,
+                    function["method_id"],
+                    Map.put(function, "abi_outputs", Map.get(function, "outputs", []))
+                  ),
+                method_id_to_outputs: method_id_to_outputs
+              }
+          end
+        end
+      )
 
-      _ ->
-        function
-        |> Map.put("abi_outputs", Map.get(function, "outputs", []))
-    end
+    methods = to_be_fetched |> Enum.map(fn {method_id, _function} -> {method_id, []} end) |> Enum.into(%{})
+
+    res =
+      contract_address_hash
+      |> query_verified_contract(methods, from, leave_error_as_map, abi, options)
+
+    method_id_to_abi_with_fetched_value =
+      res
+      |> Enum.map(fn {method_id, _result} ->
+        {outputs, function} = method_id_to_outputs[method_id]
+
+        names = outputs_to_list(function["outputs"])
+
+        outputs = link_outputs_and_values(res, outputs, method_id)
+        function = to_be_fetched[method_id]
+
+        {method_id,
+         function
+         |> Map.replace!("outputs", outputs)
+         |> Map.put("abi_outputs", Map.get(function, "outputs", []))
+         |> Map.put("names", names)}
+      end)
+      |> Enum.into(%{})
+
+    Enum.map(initial_methods_id_order, fn method_id ->
+      unchanged[method_id] || method_id_to_abi_with_fetched_value[method_id]
+    end)
   end
 
   @doc """