Add function to get ABI from non-etherscan addresses

eth_client/lib/eth_client.ex

@@ -81,6 +81,20 @@ defmodule EthClient do
  |> Rpc.call()
  end
 
+ def call_by_selector(selector, arguments) do
+ encoded_arguments = ABI.TypeEncoder.encode_raw(arguments, selector.types)
+ |> Base.encode16(case: :lower)
+
+ data = selector.method_id <> encoded_arguments
+
+ %{
+ from: Context.user_account().address,
+ to: Context.contract().address,
+ data: data
+ }
+ |> Rpc.call()
+ end
+
  def get_balance(address) do
  {balance, _lead} =
  Rpc.get_balance(address)
@@ -90,12 +104,24 @@ defmodule EthClient do
  wei_to_ether(balance)
  end
 
+ def invoke_by_selector(selector, arguments, amount) do
+ encoded_arguments = ABI.TypeEncoder.encode_raw(arguments, selector.types)
+ |> Base.encode16(case: :lower)
+ data = selector.method_id <> encoded_arguments
+
+ invoke_with_data(data, amount)
+ end
+
  def invoke(method, arguments, amount) do
- data =
- ABI.encode(method, arguments)
+ data = method
+ |> ABI.encode(arguments)
  |> Base.encode16(case: :lower)
  |> add_0x()
 
+ invoke_with_data(data, amount)
+ end
+
+ defp invoke_with_data(data, amount) do
  caller = Context.user_account()
  caller_address = String.downcase(caller.address)
  contract_address = Context.contract().address

eth_client/lib/eth_client/abi.ex

@@ -2,10 +2,57 @@ defmodule EthClient.ABI do
  @moduledoc """
  """
  alias EthClient.Context
+ alias EthClient.Rpc
+
+ # get whether it's an etherscan-linked bc: get_etherscan_api_key...
+ def get("0x" <> _ = address) do
+ if Context.etherscan_api_key() do
+ get_etherscan(address)
+ else
+ get_non_etherscan(address)
+ end
+ end
 
- def get("0x" <> _ = address), do: get_etherscan(address)
  def get(abi_path), do: get_local(abi_path)
 
+ def to_selector(function_def) do
+ selector = ABI.FunctionSelector.decode(function_def["name"])
+ selector
+ |> Map.put(:method_id, function_def["selector"])
+ |> Map.put(:state_mutability, function_def["stateMutability"])
+
+ end
+
+ defp filter_unnamed(function_def) do
+ "0x" <> function_hash = function_def.method_id
+ unknown_name = "unknown" <> function_hash
+ case Map.get(function_def, :function) do
+ ^unknown_name -> Map.delete(function_def, :function)
+ _ -> function_def
+ end
+ end
+
+ def get_non_etherscan(address) do
+ decode_path = Application.app_dir(:eth_client, "priv/decompile.py")
+ {:ok, bytecode} = Rpc.get_code(address)
+
+ case System.cmd("python3", [decode_path, bytecode]) do
+ {hashes, 0} ->
+ {:ok, funclist} = hashes
+ |> Jason.decode()
+
+ funclist = funclist
+ |> Enum.filter(fn %{"selector" => hash} -> hash != "_fallback()" end)
+ |> Enum.map(&to_selector/1)
+ |> Enum.map(&filter_unnamed/1)
+
+ {:ok, funclist}
+ {_, _} ->
+ {:error, :abi_unavailable}
+ end
+
+ end
+
  defp get_etherscan(address) do
  api_key = Context.etherscan_api_key()
 

eth_client/lib/eth_client/contract.ex

@@ -18,26 +18,79 @@ defmodule EthClient.Contract do
 
  defp parse_abi([], acc), do: {:ok, acc}
 
- defp parse_abi([%{"type" => "function"} = method_map | tail], acc) do
+ defp parse_abi([%{"type" => "function", "name" => name} = method_map | tail], acc) do
  method = %{
- name: String.to_atom(method_map["name"]),
+ name: name,
  state_mutability: method_map["stateMutability"],
  inputs: Enum.map(method_map["inputs"], fn input -> input["name"] end),
  # What's the difference between type and internal type?
  input_types: Enum.map(method_map["inputs"], fn input -> input["internalType"] end)
  }
 
- name_snake_case = String.to_atom(Macro.underscore(method_map["name"]))
+ name_snake_case = String.to_atom(Macro.underscore(name))
  function = build_function(method)
  acc = Map.put(acc, name_snake_case, Code.eval_quoted(function) |> elem(0))
 
  parse_abi(tail, acc)
  end
 
+ defp parse_abi([%{function: name} = method_map | tail], acc) do
+ function = build_function_by_hash(method_map)
+
+ selector_atom = name
+ |> Macro.underscore()
+ |> String.to_atom()
+
+ acc = Map.put(acc, selector_atom, Code.eval_quoted(function) |> elem(0))
+
+ parse_abi(tail, acc)
+ end
+
+ defp parse_abi([%{type: function, method_id: selector} = method_map | tail], acc) do
+ function = build_function_by_hash(method_map)
+
+ selector_atom = selector
+ |> String.to_atom()
+
+ acc = Map.put(acc, selector_atom, Code.eval_quoted(function) |> elem(0))
+
+ parse_abi(tail, acc)
+ end
+
  defp parse_abi([_head | tail], acc) do
  parse_abi(tail, acc)
  end
 
+ defp build_function_by_hash(%{method_id: selector, state_mutability: mutability} = method)
+ when mutability in ["pure", "view"] do
+ args = method.types
+ |> length()
+ |> Macro.generate_arguments(__MODULE__)
+
+ bound_method = Macro.escape(method)
+
+ quote do
+ fn unquote_splicing(args) ->
+ EthClient.call_by_selector(unquote(bound_method), unquote(args))
+ end
+ end
+ end
+
+ defp build_function_by_hash(%{method_id: selector} = method) do
+ args = method
+ |> Map.get(:types)
+ |> length()
+ |> Macro.generate_arguments(__MODULE__)
+
+ bound_method = Macro.escape(method)
+
+ quote do
+ fn unquote_splicing(args), amount ->
+ EthClient.invoke_by_selector(unquote(bound_method), unquote(args), amount)
+ end
+ end
+ end
+
  defp build_function(%{state_mutability: mutability} = method)
  when mutability in ["pure", "view"] do
  args = Macro.generate_arguments(length(method.inputs), __MODULE__)
@@ -60,4 +113,5 @@ defmodule EthClient.Contract do
  end
  end
  end
+
 end

eth_client/lib/eth_client/rpc.ex

@@ -18,6 +18,7 @@ defmodule EthClient.Rpc do
  def gas_price, do: send_request("eth_gasPrice", [])
  def get_transaction_by_hash(tx_hash), do: send_request("eth_getTransactionByHash", [tx_hash])
  def get_transaction_receipt(tx_hash), do: send_request("eth_getTransactionReceipt", [tx_hash])
+ def get_code(contract), do: send_request("eth_getCode", [contract, "latest"])
  def call(call_map), do: send_request("eth_call", [call_map, "latest"])
 
  def get_logs(log_map), do: send_request("eth_getLogs", [log_map])

eth_client/priv/decompile.py

@@ -0,0 +1,28 @@
+import sys
+import json
+from panoramix.decompiler import decompile_bytecode
+
+def get_hash(function_def):
+ func = {}
+ func['selector'] = function_def['hash']
+ func['name'] = function_def['abi_name']
+
+ if function_def['payable']:
+ # This needs some work
+ func['stateMutability'] = "payable"
+ else: 
+ func['stateMutability'] = "nonpayable"
+ if function_def['const']:
+ func['stateMutability'] = "view"
+
+ func['type'] = "function"
+
+ return func
+
+if len(sys.argv) != 2:
+ print("usage: python3 decode_address.py <address>", sys.argv)
+else:
+ decompilation = decompile_bytecode(sys.argv[1])
+ # Despite its name, it's not a json
+ hashes = list(map(get_hash, decompilation.json["functions"]))
+ print(json.dumps(hashes))