Call external Solidity contract with interface and delegateCall

3
votes

normally I call external contracts by importing an interface of the external contract and generating a "local variable" of the contract, once I need it. Something like this:

import "./CalleeInterface";

contract Caller {

  function callExternalFunction(address _calleeAddr){
    CalleeInternface callee = CalleeInterface(_calleeAddr);
    callee.someExternalFunction();
}

My problem is, that above way seems to use function call implicitly. Now I am facing a situation, where the external function checks the address of the sender. When I use above way, msg.sender is the address of contract Caller. Since I want to "forward" the address of the actual caller, I need to call the external function using delegatecall:

contract Caller {
  function callExternalFunction(address _calleeAddr){
    _calleeAddr.delegatecall(bytes4(keccak256("someExternalFunction()")));
}

As you can see, the interface is not required in this situation, but the code is a bit more complex. Now my question is, if there is a way to use delegatecall with the "interface way" of calling external function?

1
blockchainethereumsolidity

1 Answers

2
votes

I finally found the answer to my problem: Sadly, one cannot receive values from delegatecall function calls.