What are the exact parameters in estimateGas method of contracts?

[mbsaberi]

Hi. I've used the provided samples and something I have found in other issues to estimate the transfer function of contracts like below, but I receive errors after executing the code: My Code:

$gasLimit = 0;
$contract->at($contract_address)->estimateGas('transfer', ['from'=>'0x5e66d0a82558e0f2f8137cce1a163c6d449a658c', 'to'=>'0xa96Ce4C161271C797d979017821A278e1481eAfA', 'amount'=>1], function ($err, $gas) use (&$gasLimit) {
      if ($err !== null) {
           echo $err->getMessage();
           return false;
       } else {
            $gasLimit = $gas;
            return $gasLimit;
       }
 });

Error:

PHP Fatal error:  Uncaught InvalidArgumentException: Please make sure you have put all function params and callback.

What is the $params parameter in the estimateGas method exactly?

[mbsaberi]

@sc0Vu could you help me please?

[YonesSaeedi]

+1

[conorwatt1]

After a whole day of trying to figure this out I found the solution (hopefully this helps someone out)

In the readme it states you use this for gas estimation:

$contract->at($contractAddress)->estimateGas($functionName, $params, $callback);

What we (atleast I) assume that $params is an array to provide, in which it's not

The correct way to use this function is the following

$contract->at($contract_address)->estimateGas('transfer', $to_addr, the_number_of_tokens_to_send, ['from' => $from_addr], function($err, $resp) use (&$gas){
            if($err){
                Log::info("estimate gas error: ".$err->getMessage());
            }

            $gas = $resp->toString();
        });

Which results in:

Since I'm using infura as my provider (they don't let you unlock wallets etc), you would just need to use Web3p/ethereum-tx to sign with a private key and send..

Again, I really hope someone doesn't have to spend as much time on this now

Cheers

[nithronium]

Addition to that, for contract calls that doesn't have any input parameters, such as enableTransfers, you can use that;

$contract->at($contractAddress)->estimateGas('enableTransfers',['from' => $fromAddr],function($err,$result) use($contract) {
            if ($err !== null) {
                throw $err;
            }
            if ($result) {
                var_dump($result);
            }
        });

Which results in:

{
  ["value"]=>
  string(8) "0x018d16"
  ["engine"]=>
  string(16) "bcmath (OpenSSL)"
}

Thanks @conorwatt1 for adding the ['from' => $fromAddr] part.

[aminesmkhani]

@mbsaberi

how fix this problem?

[sc0Vu]

Thanks for your reply (@conorwatt1 @nithronium )!

Basically, the function parameter of estimate gas are: functionName, paramsToSmartContract(leave empty)... and transactionObject.

Take erc20 transfer as example:

estimateGas('transfer', $toAccount, $amount, [
    'from' => $fromAccount,
]

You can find example here: https://github.com/web3p/examples