I am trying to test this code on https://dapps.oraclize.it and each time I try to run test function, I get error VM Exception: Out of gas. However in the editor I have provided gas limit like 50000000000.
pragma solidity ^0.4.0;
import "github.com/oraclize/ethereum-api/oraclizeAPI.sol";
contract Ballot is usingOraclize {
function test() {
oraclize_query("URL", "https://api.kraken.com/0/public/Ticker?pair=ETHXBT");
}
}
Can someone help me...
the oracle query function (test) must be marked as payable and you will need to have a callback function in the contract which would be called by the oracle. Also, don't forget to send some value(ether) along with the tx.
Related
I am having problems calling functions in my smart contract that return values. I've tried changing my versions of Python, web3 and the Solidity smart contract but problems still occurs. Transact() functions work fine.The call() functions work in Truffle and Remix IDE.
My connection of Truffle and Ganache
My smart contract
Calling the function and error generated
I'm writing upgradable Smart Contracts with the Proxy Design Pattern. Here, I'm facing a challenge when I make a delegate call from the proxy contract to the logic contract methods, it throws me an error message as below.
I'm wondering what I have done wrong.
The below code is the method call in the proxy contract.
/*Delegates calls to the Logic contract*/
function setAccepted() public returns(Status){
emit setToAccept(status,now,msg.sender);
bool success;
bytes memory result;
(success,result) = delegateContract.delegatecall(abi.encodePacked(bytes4(keccak256("setAccepted()"))));
require(success);
status = abi.decode(result, (Status));
return status;
}
Logic contract code as below.
function setAccepted() public _WhenNoPaused returns(Status){
return Status.Accepted;
}
It is checked overall solidity code. I recommend studying a tutorial on proxy patterns in solidity. I attached a tutorial link.
https://github.com/rhcproc/solidity-proxy-tutorial
And I found several blogs that explained proxy patterns in solidity.
https://docs.openzeppelin.com/upgrades-plugins/1.x/proxies
https://fravoll.github.io/solidity-patterns/proxy_delegate.html
https://runtimeverification.com/blog/using-foundry-to-explore-upgradeable-contracts-part-1/
Why does Remix fail to deploy the simple contract (simplified from the Mastering Ethereum book https://github.com/ethereumbook/ethereumbook/blob/develop/code/Solidity/Faucet2.sol )? --
pragma solidity ^0.4.19;
contract Faucet {
function withdraw(uint withdraw_amount) public {
require(withdraw_amount <= 100000000000000000);
msg.sender.transfer(withdraw_amount);
}
function () external payable {}
}
No matter how I raise gasLimit and/or gasPrice
Your code is fine (I have also tried it myself). From what I see above you are also sending a value along with the deploy. Since you have not defined a constructor yourself the default one is being called which is not payable. If you want to send ether when you deploy the contract you should also define a payable constructor.
I have been attempting to deploy a contract using the Truffle framework, I have recently been testing these contracts on the development network.
My contract was very large and when I attempted to deploy it to a test net, I was instructed to split it up so that the contract wouldn't exceed the gas limit. Although, bearing in mind this contract did deploy onto the development network with the default gas limit.
So I took out parts of the contract and derived another contract from the base and added the deleted sections in there. I attempted to deploy it to the development network in order to test it again, I now get the error:
'Error: The contract code couldn't be stored, please check your gas amount.'
So the steps I took was to:
Change my gasLimit to 100,000,000 which didn't solve it
Check to see if my contract is 'abstract'
My understanding of this is that a contract is abstract if it or its
parent has any functions without an implementation. Mine don't.
I then deleted all of the code other than the constructor from the
derived contract and I still get this error
I deleted the file and the deployment worked with just my base contract as before, therefore the parent contract must not have any non-implemented functions AND it still doesn't work when I attempt to derive an empty contract from it (making sure nothing was abstract in the derived contract).
I then split my migration files up so that the migrations happen
separately, still no luck.
My parent contract is around 300 lines long so no point posting it all in here - I know some people will say 'it may just be too large' however, it deployed when it was 500 lines long on the dev network and now it is only 250 lines long with a deriving contract of 275 lines long, it does not deploy.
The error:
Running migration: 2_deploy_contracts.js
Replacing ERC20Token...
... 0xcae613274de1aa278e7ae5d1239f43445132a417d98765a4f227ea2439c9e4fc
ERC20Token: 0xeec918d74c746167564401103096d45bbd494b74
Replacing Crowdsale...
... 0x0ffc7291d84289c1391a81ed9f76d1e165285e3a3eadc065732aa288ea049b3a
Crowdsale: 0x0d8cc4b8d15d4c3ef1d70af0071376fb26b5669b
Saving successful migration to network...
... 0x7f351d76f61f7b801913f59b808688a2567b64933cdfdcf78bb18b0bf4e4ff69
Saving artifacts...
Running migration: 3_more_deployed_contracts.js
Deploying StagedSale...
... 0x216136bb24d317b140a247f10ec4d6791559739111a85932133cd4a66b12a1d9
Error encountered, bailing. Network state unknown. Review successful
transactions manually.
Error: The contract code couldn't be stored, please check your gas
amount.
at Object.callback
(/usr/local/lib/node_modules/truffle/build/cli.bundled.js:329221:46)
at /usr/local/lib/node_modules/truffle/build/cli.bundled.js:39618:25
at /usr/local/lib/node_modules/truffle/build/cli.bundled.js:331159:9
at /usr/local/lib/node_modules/truffle/build/cli.bundled.js:175492:11
at /usr/local/lib/node_modules/truffle/build/cli.bundled.js:314196:9
at XMLHttpRequest.request.onreadystatechange
(/usr/local/lib/node_modules/truffle/build/cli.bundled.js:329855:7)
My base contract is too large to post, and it deploys fine on its own meaning its not abstract.
My derived contract is:
pragma solidity ^0.4.16;
import "./SafeMath.sol";
import "./Crowdsale.sol";
contract StagedSale is Crowdsale {
using SafeMath for uint256;
/*
* Setup the contract and transfer ownership to appropriate beneficiary
*/
function StagedSale
(
uint256 _stage1Duration,
uint256 _stage2Duration
) public {
uint256 stage1duration = _stage1Duration.mul(1 minutes);
uint256 stage2duration = _stage2Duration.mul(1 minutes);
}
My migration file for the derived contract:
var StagedSale = artifacts.require("./StagedSale.sol");
module.exports = function(deployer) {
const stage1Duration = 1;
const stage2Duration = 1;
deployer.deploy(StagedSale, stage1Duration, stage2Duration);
};
I have posted this question here as I fear this may be a common issue with Truffle deployment.
To conclude, I don't believe this has anything to do with the actual gas limits and is instead, failing for some unknown reason and printing this error message anyway.
I've found a fix to this, basically if you are inheriting from a base contract, you must deploy the base contract within the inherited contracts constructor like so:
OLD VERSION:
Simply deployed the base, then deployed the inheriting contract with a reference to 'is Crowdsale' in class name
deployer.deploy(ERC20Token, initialAmount, tokenName, decimalUnits,tokenSymbol).then(function() {
return deployer.deploy(Crowdsale, softCap, hardCap, etherCostOfEachToken, sendFundsTo, toChecksumAddress(ERC20Token.address), durationInMinutes);
});
deployer.deploy(FinalizableSale);
NEW VERSION
Only deploy the inheriting contract and create a new instance of base within that constructor
deployer.deploy(ERC20Token, initialAmount, tokenName, decimalUnits,tokenSymbol).then(function() {
return deployer.deploy(Finalizable, softCap, hardCap, etherCostOfEachToken, sendFundsTo, toChecksumAddress(ERC20Token.address), durationInMinutes);
});
FINALIZABLE CONSTRUCTOR:
function FinalizableSale(uint256 _fundingGoalInEthers, uint256 _fundingLimitInEthers, uint256 _etherCostOfEachToken, address _sendFundsTo, address _tokenAddress, uint256 _durationInMinutes)
Crowdsale(_fundingGoalInEthers, _fundingLimitInEthers, _etherCostOfEachToken, _sendFundsTo, _tokenAddress, _durationInMinutes)
{
//do something
}
NOTE: That the base contract is initialised BEFORE the opening brackets to the constructor function.
I no longer get the 'out of gas' error and my contract runs as before.
Trying to follow the wiki example for go ethereum to create a basic contract:
https://github.com/ethereum/go-ethereum/wiki/Contracts-and-Transactions
Everything seems to work until I get down until the last line:
source = "contract test { function multiply(uint a) returns(uint d) { return a * 7; } }"
contract = eth.compile.solidity(source).test
primaryAddress = eth.accounts[0]
# **Problems start here **
MyContract = eth.contract(abi);
contact = MyContract.new(arg1, arg2, ...,{from: primaryAddress, data: evmCode})
What is the "abi" argument for the eth.contract method? Also, what would I put in the "evmCode" argument? In this particular example, seems like I would put in an integer for "arg1" but not sure what the full example should look like.
The ABI is the interface that your contract exposes. "evmCode" is the Ethereum byte code for your contract.
To work around your problem, go to https://chriseth.github.io/browser-solidity/ and plug your Solidity in. The Bytecode field on the right will give you the value for "evmCode" and Interface will give you the ABI.
You can also copy the snippet from "Web3 deploy" and paste it in your code to deploy your contract.
ABI is basically which is the public facing interface that shows what methods are available to call.
The simplest way to get the abi would be to use https://remix.ethereum.org . just paste in your code and in Contract tab At the bottom of the column you’ll find a link that says Contract details which is basically the ABI json
Conversely you could also use the contracts.Introduction.interface api of web3 to get the abi.
ABI is representation of smart contract that can be read using java script .To read the data from a deployed contract account in etherum , you'll need some extra details like abi.
Steps to get abi of any smart contract:
1.Each contract has contract hash address like this:0x0D8775F648430679A709E98d2b0Cb6250d2887EF
2.Go to etherscan.io and search your contract address hash in search bar and you will get contract.
3.In contract go to code and there you can find this abi
can check this link to find abi
You could try using tools like Etherlime shape or Truffle boxes to have a whole sample project with contract, tests, and usage into the js. From here you could start moving forward.
ABI is Application Binary Interface. A contract when compiled by solidity compiler returns an object with different methods. ABI and Bytecode are basically used methods. ABI is used to interact with your contracts and frontend (if using node) and bytecode is used for deploying to Rinkeby (or any Ethereum network).
For example:
Contract is:
pragma solidity ^0.4.17;
contract Inbox
{
string public message;
function Inbox(string initialMessage) public{
message = initialMessage;
}
function setMessage(string newMessage) public{
message = newMessage;
}
}
Its ABI is:
interface:
[{
"constant":false,"inputs":[{
"name":"newMessage","type":"string"
}]
,"name":"setMessage","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"
}
,{
"constant":true,"inputs":[],"name":"message","outputs":[{
"name":"","type":"string"
}]
,"payable":false,"stateMutability":"view","type":"function"
}
,{
"inputs":[{
"name":"initialMessage","type":"string"
}]
,"payable":false,"stateMutability":"nonpayable","type":"constructor"
}]
This is returned after compiling the contract. You can see it consists of methods used in our contract.