How to check values of a variables and functions in solidity like javascript via console.log? Because i need visibility of results for deep understanding.
I am newbie...
i tried hardhat but need more understand.
I'm a newbie too, but I know this (I think)!
There is no console in solidity, you need to write a function for this, or just put it public in the variable itself!
// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;
contract Value {
uint public num; //add "public" to see the value
function add(uint _num) external{
num += _num;
}
//this function is for returning value
function viewNum() public view returns(uint){
return(num);
}
}
Also use the Remix editor, it's in the browser. There are plenty of videos on the internet!
If you are using hardhat, then you can use console.sol.
You need to import it into your contract.
import "hardhat/console.sol";
Now, you are able to log your variable while you are working.
console.log(__your_variable__);
If you are still looking to log your variables once you deploy your contract, then you need to use event functionality.
Import hardhat console:
import "hardhat/console.sol";
Use console log in your contract
console.log(variable); //Variable value
console.log(1234); //direct value
I've got a Chainlink client contract which makes a DirectRequest to an oracle. The oracle does its thing and then returns the answer via the typical callback selector passed in via the ChainlinkRequest. It all works well, but I'd like to write some tests that test the callback implementation
My client contract is as follows:
contract PriceFeed is Ownable, ChainlinkClient {
function updatePrice() onlyOwner returns (bytes32 requestId) {
// makes Chainlink request specifying callback via this.requestCallback.selector
}
function requestCallback(bytes32 _requestId, uint256 _newPrice) public
recordChainlinkFulfillment(_requestId) {
price = _newPrice;
}
}
The problem arises when the test code calls requestCallback(...) and the code hits the recordChainlinkFulfillment(...) modifier. The ChainlinkClient complains that the requestId being passed in by the test below isn't in the underling private pendingRequests mapping maintained by the ChainlinkClient.
The simplified version of ChainlinkClient looks like this:
contract ChainlinkClient {
mapping(bytes32 => address) private pendingRequests;
modifier recordChainlinkFulfillment(bytes32 _requestId) {
require(msg.sender == pendingRequests[_requestId], "Source must be the oracle of the request");
delete pendingRequests[_requestId];
emit ChainlinkFulfilled(_requestId);
_;
}
}
My Foundry/Solidity test is as follows:
contract PriceFeedTest is Test {
function testInitialCallback() public {
priceFeed.requestCallback("abc123", 1000000); // fails on this line
assertEq(1000000, priceFeed.price(), "Expecting price to be 1000000");
}
}
The code fails on first line of the testInitialCallback() line with: Source must be the oracle of the request
How can I trick the ChainklinkClient into allowing my callback to get past the modifier check? AFAIK I can't access and pre-populate the private pendingRequests mapping. Is there another way?
I know that Foundry provides Cheatcodes to help in testing and there's a stdstorage cheatcode, but I'm not familiar on how to construct a call to stdstorage to override pendingRequests if thats even possible with a cheatcode.
contract PriceFeedTest is Test {
function testInitialCallback2() public {
stdstore
.target(address(priceFeed))
.sig("pendingRequests()")
.with_key("abc123")
.checked_write(address(this));
priceFeed.requestCallback("abc123", 1000000);
assertEq(1000000, priceFeed.price(), "Expecting price to be 1000000");
}
}
The above code throws the following error: No storage use detected for target
Any help would be greatly appreciated. Many thanks.
When you execute the updatePrice function in your test, you should be able to strip out the requestId from the transaction receipt event. Once you have that, you can then use it in your call to requestCallback. Check out this example unit test from the hardhat starter kit for an example of this
I want to use Oraclize in Remix, to test it. I'm too stupid to use their examples.
How can I make this work?
From their Github I took the YouTube-Views code and copied it into Remix
pragma solidity >= 0.5.0 < 0.6.0;
import "github.com/oraclize/ethereum-api/oraclizeAPI.sol";
contract YoutubeViews is usingOraclize {
string public viewsCount;
event LogYoutubeViewCount(string views);
event LogNewOraclizeQuery(string description);
constructor()
public
{
update(); // Update views on contract creation...
}
function __callback(
bytes32 _myid,
string memory _result
)
public
{
require(msg.sender == oraclize_cbAddress());
viewsCount = _result;
emit LogYoutubeViewCount(viewsCount);
// Do something with viewsCount, like tipping the author if viewsCount > X?
}
function update()
public
payable
{
emit LogNewOraclizeQuery("Oraclize query was sent, standing by for the answer...");
oraclize_query("URL", 'html(https://www.youtube.com/watch?v=9bZkp7q19f0).xpath(//*[contains(#class, "watch-view-count")]/text())');
}
}
When I use the viewCount it returns:
0: string:
This happens with all the other examples aswell.
With WolframAlpha eg. I also get the following error:
transact to WolframAlpha.update errored: VM error: revert.
revert The transaction has been reverted to the initial state.
Note: The constructor should be payable if you send value. Debug the transaction to get more information.
Ok you don't see the answer like a normal result in Remix:
You have to go under settings and open the Oraclize plug in.
If you then deploy the contract and or click update, you get the result shown in the plug in.
I am trying to run a bidding smart contract on a private blockchain and my smart contract is working on the Remix IDE and the same works on my private chain except for one function [dataOwnedBy()] which is suposed to return an array of bytes32 but returns all zero values in geth console.
I have compiled and deployed my smart contract using truffle.
The function which is not working is : (along with data declaration snippet and other function prototypes)
struct data{
bytes32 data_id;
address bidder;
uint bid;
}
mapping(bytes32=>data) bidInfo;
mapping(address=>data[]) dataOwned; //data owned by each address
address[] dataOwners; //list of address who own data
function Bid(bytes32 data_id) public payable { ... }
function closeBid(bytes32 data_id) public { ... }
function whoOwns(bytes32 _data_id) constant public returns (address){ ... }
function dataOwnedBy(address _addr) constant public returns (bytes32[10]){
uint length = dataOwned[_addr].length;
bytes32[10] memory _idArray;
for (uint i=0;i<length;i++){
_idArray[i] = (dataOwned[_addr][i].data_id);
}
return _idArray;
}
After closing the bid, when I query the above function with the winner's address, it returns array of size 10 bytes32 values, all equal to zero, where it should be returning the data_ids owned by the address.!
Version Information from console
> web3.version.api
"0.20.1"
truffle(development)> version
Truffle v3.4.11 (core: 3.4.11)
Solidity v0.4.15 (solc-js)
This is the console output :
playbid.whoOwns("data_id1")
"0x7d8eb703bd863313325b784ac35017614484f2e7"
playbid.dataOwnedBy("0x7d8eb703bd863313325b784ac35017614484f2e7")
["0x0000000000000000000000000000000000000000000000000000000000000000", "0x0000000000000000000000000000000000000000000000000000000000000000", "0x0000000000000000000000000000000000000000000000000000000000000000", "0x0000000000000000000000000000000000000000000000000000000000000000", "0x0000000000000000000000000000000000000000000000000000000000000000", "0x0000000000000000000000000000000000000000000000000000000000000000", "0x0000000000000000000000000000000000000000000000000000000000000000", "0x0000000000000000000000000000000000000000000000000000000000000000", "0x0000000000000000000000000000000000000000000000000000000000000000", "0x0000000000000000000000000000000000000000000000000000000000000000"]
Instead the first value of the array should be the hex of "data_id1".
Don't know what is going wrong here, but it works perfectly fine on Remix IDE.
Thanks in advance !
As your code is working OK in remix, there is no problem with the smart contract code. I experienced same issue when I wanted to return some arrays back to my web3j powered java app. I also tested web3js and encountered the same problem. The returned array was broken the same way.
I ended up in serializing and deserializing arrays to strings with a delimiter, both in inputs and outputs.
I'm trying to change the state variable value of solidity, and test on the geth console, but the value of state variable is not changed.
The steps are as below：
1: Write a simple smart contract code by solidity as below
pragma solidity ^0.4.0;
contract SimpleStorage {
uint public storedData=99;
mapping(string => uint) balances;
function set(uint x) public returns (uint){
storedData = x;
return storedData;
}
function get() public constant returns (uint) {
return storedData;
}
function multiply(uint a) returns(uint d) {
return a * 7;
}
function setmapping(string key,uint value) returns(uint v)
{
balances[key] = value;
return balances[key];
}
function getmapping(string key) returns(uint v)
{
return balances[key];
}
function kill()
{
}
}
2: compile the code by the truffle, use command
truffle compile
3:start the geth, unlock account, and start the minner
4:deploy the smart contract
truffle migration --reset
and then I see the console output as below
Using network 'development'.
Running migration: 1_initial_migration.js
Replacing Migrations...
... 0x8ccf9e1599c2760ff3eed993be10929403e1faa05489a247a067f4f06536c74c
Migrations: 0xec08113a9e810e527d99a1aafa8376425c4a75ed
Saving successful migration to network...
... 0xedbf12715b736759e9d9297cbaaeb3151d95f478c2f1ee71bff4819d2dbb47e5
Saving artifacts...
Running migration: 2_deploy_contracts.js
Replacing SimpleStorage...
... 0xff5b00f9b14d8ecea4828c3ad8e9dbfa9d685bc0b81530fc346759d7998b060f
SimpleStorage: 0x96cf1e076f4d99a5d0823bd76c8de6a3a209d125
Saving successful migration to network...
... 0x3452a9e76b73e250de80874ebc3fd454724ebf6a15563bee0d5ba89b7b41909f
Saving artifacts...
which means the smart contract deployed to geth successfully
5: Then in the geth console, I set abi variable as below:
abi=[{"constant":true,"inputs":[],"name":"storedData","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"changeStorage","outputs":[],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"kill","outputs":[],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"getAll","outputs":[{"name":"","type":"uint256"},{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"x","type":"uint256"}],"name":"set","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"get","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"key","type":"string"},{"name":"value","type":"uint256"}],"name":"setmapping","outputs":[{"name":"v","type":"uint256"}],"payable":false,"type":"function"},{"constant":true,"inputs":[{"name":"","type":"uint256"}],"name":"refrenceType","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"changeMemory","outputs":[],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"key","type":"string"}],"name":"getmapping","outputs":[{"name":"v","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"a","type":"uint256"}],"name":"multiply","outputs":[{"name":"d","type":"uint256"}],"payable":false,"type":"function"}]
6: Get an contract instant as below:
test=eth.contract(abi).at("0x2f3970e8e4e2f5ed4ccb37b0f79fe5598700e2f0")
7: Run the set()
test.set.call(22);
The out put is 22, which I think the state variable storedData was successfully set to the new value 22, but when I run below code to read the storedData,
test4.get()
the return value is still 99, which mean the value of storedData was not changed, beside use the uint to do the testing, I also tried the mapping, but the answer is as same as uint, I don't know if I was wrong in somewhere or the state variable is not allowed to be modified, could anyone help me?
Thanks.
From the question, this is the call that is not changing state:
test.set.call(22)
In order to change state, you must issue a transaction. A call(...) only tells you what would happen if you were to send a transaction. For more background, see: What is the difference between a transaction and a call?
So you can replace the above line with:
test.set.sendTransaction(22)
Alternatively, web3.js will automatically attempt to decide whether to use a transaction or a call. So in this case you can use simply:
test.set(22)
For more background on how web3.js decides, see: How does web3.js decide to run a call() or sendTransaction() on a method call?