add ERC-721 info to transaction overview page

apps/block_scout_web/lib/block_scout_web/templates/transaction/overview.html.eex

@@ -138,8 +138,9 @@
       </div>
     </div>
 
-    <% token_transfer = assigns[:token_transfers] && erc20_token_transfer(@transaction, @token_transfers) %>
-    <%= if token_transfer do %>
+    <%= cond do %>
+      <% erc20_token_transfer = assigns[:token_transfers] && erc20_token_transfer(@transaction, @token_transfers) -> %>
+
         <div class="col-md-12 col-lg-4 d-flex flex-column flex-md-row flex-lg-column">
         <!-- Value -->
         <div class="card card-primary flex-grow-1">
@@ -148,14 +149,31 @@
             <div class="text-right">
               <h3 class="text-white">
                 <span class="col-12 col-md-7 ml-3 ml-sm-0">
-                  <%= token_transfer_amount(token_transfer) %>
-                  <%= link(token_symbol(token_transfer.token), to: token_path(BlockScoutWeb.Endpoint, :show, token_transfer.token.contract_address_hash)) %>
+                  <%= token_transfer_amount(erc20_token_transfer) %>
+                  <%= link(token_symbol(erc20_token_transfer.token), to: token_path(BlockScoutWeb.Endpoint, :show, erc20_token_transfer.token.contract_address_hash)) %>
                 </span>
               </h3>
             </div>
           </div>
         </div>
-    <% else %>
+      <% erc721_token_transfer = assigns[:token_transfers] && erc721_token_transfer(@transaction, @token_transfers) -> %>
+
+        <div class="col-md-12 col-lg-4 d-flex flex-column flex-md-row flex-lg-column">
+        <!-- Value -->
+        <div class="card card-primary flex-grow-1">
+          <div class="card-body">
+            <h2 class="card-title text-white"><%= gettext "ERC-721" %> <%= gettext "Token Transfer" %></h2>
+            <div class="text-right">
+              <h3 class="text-white">
+                <span class="col-12 col-md-7 ml-3 ml-sm-0">
+                  <%= token_transfer_amount(erc721_token_transfer) %>
+                  <%= link(token_symbol(erc721_token_transfer.token), to: token_path(BlockScoutWeb.Endpoint, :show, erc721_token_transfer.token.contract_address_hash)) %>
+                </span>
+              </h3>
+            </div>
+          </div>
+        </div>
+      <% true -> %>
         <div class="col-md-12 col-lg-4 d-flex flex-column flex-md-row flex-lg-column">
         <!-- Value -->
         <div class="card card-primary flex-grow-1">

apps/block_scout_web/lib/block_scout_web/views/transaction_view.ex

@@ -48,30 +48,67 @@ defmodule BlockScoutWeb.TransactionView do
       {unquote(TokenTransfer.transfer_function_signature()) <> params, ^zero_wei} ->
         types = [:address, {:uint, 256}]
 
-        try do
-          [address, value] =
-            params
-            |> Base.decode16!(case: :mixed)
-            |> TypeDecoder.decode_raw(types)
+        [address, value] = decode_params(params, types)
 
         decimal_value = Decimal.new(value)
 
         Enum.find(token_transfers, fn token_transfer ->
           token_transfer.to_address_hash.bytes == address && token_transfer.amount == decimal_value
         end)
-        rescue
-          _ -> nil
-        end
 
       _ ->
         nil
     end
+  rescue
+    _ -> nil
   end
 
   def erc20_token_transfer(_, _) do
     nil
   end
 
+  def erc721_token_transfer(
+        %Transaction{
+          status: :ok,
+          created_contract_address_hash: nil,
+          input: input,
+          value: value
+        },
+        token_transfers
+      ) do
+    zero_wei = %Wei{value: Decimal.new(0)}
+
+    # https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/token/ERC721/ERC721.sol#L35
+    {from_address, to_address} =
+      case {to_string(input), value} do
+        {"0x23b872dd" <> params, ^zero_wei} ->
+          types = [:address, :address, {:uint, 256}]
+          [from_address, to_address, _value] = decode_params(params, types)
+          {from_address, to_address}
+
+        {"0x42842e0e" <> params, ^zero_wei} ->
+          types = [:address, :address, {:uint, 256}]
+          [from_address, to_address, _value] = decode_params(params, types)
+          {from_address, to_address}
+
+        {"0xb88d4fde" <> params, ^zero_wei} ->
+          types = [:address, :address, {:uint, 256}, :bytes]
+          [from_address, to_address, _value, _data] = decode_params(params, types)
+          {from_address, to_address}
+
+        _ ->
+          nil
+      end
+
+    Enum.find(token_transfers, fn token_transfer ->
+      token_transfer.from_address_hash.bytes == from_address && token_transfer.to_address_hash.bytes == to_address
+    end)
+  rescue
+    _ -> nil
+  end
+
+  def erc721_token_transfer(_, _), do: nil
+
   def processing_time_duration(%Transaction{block: nil}) do
     :pending
   end
@@ -298,4 +335,10 @@ defmodule BlockScoutWeb.TransactionView do
   defp tab_name(["token_transfers"]), do: gettext("Token Transfers")
   defp tab_name(["internal_transactions"]), do: gettext("Internal Transactions")
   defp tab_name(["logs"]), do: gettext("Logs")
+
+  defp decode_params(params, types) do
+    params
+    |> Base.decode16!(case: :mixed)
+    |> TypeDecoder.decode_raw(types)
+  end
 end

apps/block_scout_web/test/block_scout_web/views/transaction_view_test.exs

@@ -47,6 +47,30 @@ defmodule BlockScoutWeb.TransactionViewTest do
     end
   end
 
+  describe "erc721_token_transfer/2" do
+    test "finds token transfer" do
+      from_address_hash = "0x7a30272c902563b712245696f0a81c5a0e45ddc8"
+      to_address_hash = "0xb544cead8b660aae9f2e37450f7be2ffbc501793"
+      from_address = insert(:address, hash: from_address_hash)
+      to_address = insert(:address, hash: to_address_hash)
+      block = insert(:block)
+
+      transaction =
+        insert(:transaction,
+          input:
+            "0x23b872dd0000000000000000000000007a30272c902563b712245696f0a81c5a0e45ddc8000000000000000000000000b544cead8b660aae9f2e37450f7be2ffbc5017930000000000000000000000000000000000000000000000000000000000000002",
+          value: Decimal.new(0),
+          created_contract_address_hash: nil
+        )
+        |> with_block(block, status: :ok)
+
+      token_transfer =
+        insert(:token_transfer, from_address: from_address, to_address: to_address, transaction: transaction)
+
+      assert TransactionView.erc721_token_transfer(transaction, [token_transfer]) == token_transfer
+    end
+  end
+
   describe "processing_time_duration/2" do
     test "returns :pending if the transaction has no block" do
       transaction = build(:transaction, block: nil)