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1 vote
2 answers
823 views

How to track incoming to smart contract transactions using web3js?

I've got one Ethereum smart contract which calls functions of the other one. How could I track these calls using web3js or some other tool if it is possible at all? I need it because I want to execute ...
1 vote
1 answer
682 views

How to simulate multiple consecutive transactions and get the resulting state?

I'm trying to simulate a transaction on the public blockchain that invokes a contract's method with certain parameters. Then I want to make a follow-up transaction with some other method call. I ...
195 votes
2 answers
60k views

What is the difference between a transaction and a call?

What is the difference between a transaction and a call? In some interfaces, I can interact with contracts via calls or via transactions. What is the difference between the two, and can contracts also ...
6 votes
1 answer
15k views

Execute transaction Approve directly against contract address (without ABI)

Solved For now, you will always need the ABI to execute a call against the ethereum network with web3. A simple way is to reconstruct the function you wish to execute is to, either create a separate ...
1 vote
0 answers
259 views

How to access data from web3.eth.Contracts.send() function?

If I run this chunk of code from my async function I will get a transaction receipt as an output: const response = await contract.methods.recoverAddr(hex_msg, v_decimal,r, s).send({from: accounts[0]}...
2 votes
1 answer
6k views

How to Deploy and call a contract? Address needed beforehand?

I want to store a string from a script in node.js to blockchain. This is the contract. pragma solidity ^0.4.0; contract SimpleStorage { string storedData; function set(string x) { ...
0 votes
1 answer
224 views

Sending parameters via the transaction Object

This works just fine: myContractObject.doSomething(i, function(err, result) { if (err) { console.log(err) } else { doSomethingElse(result) } }) However, this doesn't: ...
0 votes
1 answer
171 views

How to form the transactionObject in a metamask enforced async call?

Normally, for a contract call (i.e. something that does not update ethereum), I would simply do: var something = myContractObject.getSomething(). I've just started using metamask, and unfortunately, ...
7 votes
1 answer
3k views

Passing ether with call to Solidity function

I have deployed a contract to testnet which appears to function. I have a function named contribute which gets the ether from the msg.value. The function is below and doesn't take any arguments. I ...
4 votes
1 answer
6k views

Can I send ethereum to a contract outside of its constructor?

How do I fund Solidity contracts with Ether? The example in the Solidity FAQ, http://solidity.readthedocs.io/en/develop/frequently-asked-questions.html#store-ether-in-a-contract, funds a contract via ...
4 votes
1 answer
936 views

When a contract calls another contracts, can it return values?

When a contract calls another contract, are values returned ? I've seen things like: function foo() external returns (bool success) { if( ... ) throw; return true; } But have read that calls ...
3 votes
1 answer
2k views

NodeJS+web3 - Reading from a contract works, how about writing to a contract? [duplicate]

In Mist you can call functions of contracts in two ways: On the left panel, to call functions that read from a contract (the result is immediate). On the right panel, to call functions that write ...