allow bytes32 for name and symbol

apps/ethereum_jsonrpc/lib/ethereum_jsonrpc/contract.ex

@@ -28,10 +28,11 @@ defmodule EthereumJSONRPC.Contract do
 
   @spec execute_contract_functions([call()], [map()], EthereumJSONRPC.json_rpc_named_arguments()) :: [call_result()]
   def execute_contract_functions(requests, abi, json_rpc_named_arguments) do
-    functions =
+    parsed_abi =
       abi
       |> ABI.parse_specification()
-      |> Enum.into(%{}, &{&1.function, &1})
+
+    functions = Enum.into(parsed_abi, %{}, &{&1.function, &1})
 
     requests_with_index = Enum.with_index(requests)
 
@@ -58,7 +59,8 @@ defmodule EthereumJSONRPC.Contract do
           {:error, "No result"}
 
         response ->
-          {^index, result} = Encoder.decode_result(response, functions[function_name])
+          selectors = Enum.filter(parsed_abi, fn p_abi -> p_abi.function == function_name end)
+          {^index, result} = Encoder.decode_result(response, selectors)
           result
       end
     end)

apps/ethereum_jsonrpc/lib/ethereum_jsonrpc/encoder.ex

@@ -35,12 +35,28 @@ defmodule EthereumJSONRPC.Encoder do
   @doc """
   Given a result from the blockchain, and the function selector, returns the result decoded.
   """
-  @spec decode_result(map(), %ABI.FunctionSelector{}) ::
+  @spec decode_result(map(), %ABI.FunctionSelector{} | [%ABI.FunctionSelector{}]) ::
           {String.t(), {:ok, any()} | {:error, String.t() | :invalid_data}}
   def decode_result(%{error: %{code: code, message: message}, id: id}, _selector) do
     {id, {:error, "(#{code}) #{message}"}}
   end
 
+  def decode_result(result, selectors) when is_list(selectors) do
+    Enum.map(selectors, fn selector ->
+      try do
+        decode_result(result, selector)
+      rescue
+        _ -> :error
+      end
+    end)
+    |> Enum.find(fn decode ->
+      case decode do
+        {_id, {:ok, _}} -> true
+        _ -> false
+      end
+    end)
+  end
+
   def decode_result(%{id: id, result: result}, function_selector) do
     types_list = List.wrap(function_selector.returns)
 

apps/explorer/lib/explorer/token/metadata_retriever.ex

@@ -22,6 +22,16 @@ defmodule Explorer.Token.MetadataRetriever do
       "payable" => false,
       "type" => "function"
     },
+    %{
+      "constant" => true,
+      "inputs" => [],
+      "name" => "name",
+      "outputs" => [
+        %{"name" => "", "type" => "bytes32"}
+      ],
+      "payable" => false,
+      "type" => "function"
+    },
     %{
       "constant" => true,
       "inputs" => [],
@@ -60,6 +70,19 @@ defmodule Explorer.Token.MetadataRetriever do
       ],
       "payable" => false,
       "type" => "function"
+    },
+    %{
+      "constant" => true,
+      "inputs" => [],
+      "name" => "symbol",
+      "outputs" => [
+        %{
+          "name" => "",
+          "type" => "bytes32"
+        }
+      ],
+      "payable" => false,
+      "type" => "function"
     }
   ]
 

apps/explorer/test/explorer/token/metadata_retriever_test.exs

@@ -426,4 +426,51 @@ defmodule Explorer.Token.MetadataRetrieverTest do
       on_exit(fn -> Application.put_env(:explorer, :token_functions_reader_max_retries, original) end)
     end
   end
+
+  test "returns name and symbol when they are bytes32" do
+    token = insert(:token, contract_address: build(:contract_address))
+
+    expect(
+      EthereumJSONRPC.Mox,
+      :json_rpc,
+      1,
+      fn requests, _opts ->
+        {:ok,
+         Enum.map(requests, fn
+           %{id: id, method: "eth_call", params: [%{data: "0x313ce567", to: _}, "latest"]} ->
+             %{
+               id: id,
+               result: "0x0000000000000000000000000000000000000000000000000000000000000012"
+             }
+
+           %{id: id, method: "eth_call", params: [%{data: "0x06fdde03", to: _}, "latest"]} ->
+             %{
+               id: id,
+               result: "0x4d616b6572000000000000000000000000000000000000000000000000000000"
+             }
+
+           %{id: id, method: "eth_call", params: [%{data: "0x95d89b41", to: _}, "latest"]} ->
+             %{
+               id: id,
+               result: "0x4d4b520000000000000000000000000000000000000000000000000000000000"
+             }
+
+           %{id: id, method: "eth_call", params: [%{data: "0x18160ddd", to: _}, "latest"]} ->
+             %{
+               id: id,
+               result: "0x00000000000000000000000000000000000000000000d3c21bcecceda1000000"
+             }
+         end)}
+      end
+    )
+
+    expected = %{
+      decimals: 18,
+      name: "Maker",
+      symbol: "MKR",
+      total_supply: 1_000_000_000_000_000_000_000_000
+    }
+
+    assert MetadataRetriever.get_functions_of(token.contract_address_hash) == expected
+  end
 end