web3j/web3j

Lightweight Java library for integration with Ethereum clients

ruchita

@ruchita.ladha_gitlab

@iikirilov : thank you!

Soumyadip Chowdhury

@soumyadip007

Credentials credentials =
WalletUtils.loadCredentials(
"12341234",
"/path/to/wallet");
log.info("Credentials loaded");

Can anyone please tell me what will be the path?

How to generate this?

Error:
01:27:50.610 [main] INFO org.web3j.sample.Application - Connected to Ethereum client version: Geth/v1.9.8-omnibus-f14759fb-20191127/linux-amd64/go1.13.4
Exception in thread "main" java.io.FileNotFoundException: \path\to\wallet (The system cannot find the path specified)
at java.io.FileInputStream.open0(Native Method)

Ivaylo Kirilov

@iikirilov

@soumyadip007 the path is to a wallet file like - UTC--2020-06-25T07-44-09.754000000Z--417584778fff87b92cc1b669d4741eb4e677d39f.json

Soumyadip Chowdhury

@soumyadip007

@iikirilov , could you please tell me that how can I locate the Rinkeby wallet path, I've setup one rinkeby network, should I put this path?

Soumyadip Chowdhury

@soumyadip007

If I try to create a local private wallet web3J Wallet then getting this error.

Soumyadip@DESKTOP-INVVN9F MINGW64 ~/Desktop/BlockChain Total
$ web3j wallet create
Exception in thread "main" java.lang.NullPointerException
at org.web3j.console.ConsoleDevice.readPassword(ConsoleDevice.java:24)
at org.web3j.console.WalletManager.getPassword(WalletManager.java:35)
at org.web3j.console.WalletCreator.run(WalletCreator.java:34)
at org.web3j.console.WalletCreator.main(WalletCreator.java:26)
at org.web3j.console.WalletRunner.main(WalletRunner.java:23)
at org.web3j.console.WalletRunner.run(WalletRunner.java:14)
at org.web3j.console.Runner.main(Runner.java:35)

Ivaylo Kirilov

@iikirilov

@soumyadip007 metamask is a browser wallet - you will have to export your wallet to a file and load it with web3j

Soumyadip Chowdhury

@soumyadip007

@iikirilov Thanks

Nick Ivanov

@nick-ivanov

Hello everyone. What would be the right way to put together a bunch of values of different types for signing, so that it could match abi.encodePacked in Solidity?

Specifically, I have a tuple (address, address, uint256, uint32). I have exhausted all possible ways to concatenate them. I do use the Ethereum prefix, but the signatures still don't match.

In web3js, this does the trick:

var hash = web3.utils.soliditySha3(
{t: 'address', v: client}, {t: 'address', v: hotspot}, {t: 'uint256', v: amount}, {t: 'uint32', v: timestamp}
);

return signature_json = web3.eth.accounts.sign(
hash,
'<private key here>'
);

Do you know how to do the same in Web3j? Thank you in advance!

Evan Saulpaugh

@esaulpaugh

@nick-ivanov my java library does packed encoding like

TupleType.parse("(address,address,uint256,uint32)").encodePacked(new Tuple(BigInteger.ONE, BigInteger.ONE, BigInteger.ONE, 1L))

-->

00000000000000000000000000000000000000010000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000100000001

; would that help? https://github.com/esaulpaugh/headlong/blob/master/src/main/java/com/esaulpaugh/headlong/abi/TupleType.java actually I think I forgot to add this feature to the command line interface. I should add it

Evan Saulpaugh

@esaulpaugh

headlong-cli will now do packed encoding. java -jar headlong-cli-0.4-SNAPSHOT-interface.jar -ep "(uint16,uint24)" "('01','ff')" --> 00010000ff i will see about implementing the decoder as well

pringinacio

@pringinacio

I would like to add a feature to WalletUtils (org.web3j.crypto), so that when generating a wallet does not necessarily create a file. It can, for example, return only the Json content of WalletFile (objectMapper.writeValueAsString(walletFile);)

Ivaylo Kirilov

@iikirilov

@nick-ivanov web3j does not have a easy way to do packed encoding for you - everything get poadded to 32 bytes by default

sofaki000

@sofaki000

Hello guys!im using a gradle web3j plugin to compile smart contracts and generate wrapper java classes to interact with them.however this happens at build time.i want it to happen at runtime.do you have any idea how to compile smart contracts at runtime without using cmd tools?thanks a lot!

Ivaylo Kirilov

@iikirilov

@sofaki000 yes it is possible you can pass the relevant arguments to SolidityFunctionWrapperGenerator from web3j:codegen

make sure you load the generated wrappers in the classpath to use it :)

Pylyp Radionov

@rad-p

hi all, I got simple contract greeter

pragma solidity 0.6.6;

contract Greeter {

    string word;

    constructor() public {
        word = "Hello from constructor";
    }

    function getWord() public view returns(string memory) {
        return word;
    }
}

and after using web3j wrapper, the getWord functions returns RemoteFunctionCall

 public RemoteFunctionCall<TransactionReceipt> getWord() {
        final Function function = new Function(
                FUNC_GETWORD, 
                Arrays.<Type>asList(), 
                Collections.<TypeReference<?>>emptyList());
        return executeRemoteCallTransaction(function);
    }

but according to docs, it should return type, as its not a transaction, but rather a eth_call
docs.web3j.io/smart_contracts/#calling-constant-methods

Vince BCD

@BCDiploma_gitlab

Hi guys, we face this kind of error on ropsten for a few hours :

Failure extracting data from Ethereum transaction receipt 0x877....

Any idea?

mhadhbi oumaima

@MHADHBIoumaima_gitlab

I want to pass this as input for a function call with web3j [["0x207e2346c77ab01529aa39dbf9bbc93ee85bd3bf6ad583f53d1ed5ac1fd85837", "0x0178e5a86eca5347e62ad37356e4c36b2d4e5cb043da93f922fb9a497f958247"], [["0x1ac6921597c999911bc8064722875bdfd2157f3d6278a1a12e1f4a27a063d173", "0x24db42163adfb1d6212fff6b8a4e414aec35d239b54a7443df40d5226289fbf7"], ["0x1a2b44db88cd4d0dd069a0220ef39b6b540598d1f1849636cd266f15260f22d7", "0x03f8bafc4b085bcb99779b6004836a047a496c5c2e0ae0bdc0e03f0552eefe07"]], ["0x23c40fd5d4564017ef81905c3bff16dfc4ccae06520d2457b4a351b1d8f315da","0x02055f9ef9f510ed3966e55046487421db1d831c416825af8b58d943532ac65e"] ], any ideas ?

Conor Svensson

@conor10

For all you Web3j users - we’ve just released our first Web3j survey, it would be great to get feedback from any users here! https://forms.gle/G4PNL7jMGAMpuYxo6

www.dobeho.com

@dobesthosting_twitter

while transffering erc20 token if i send 200 means it transfer 0.0000000000000002 i dont know why its happened please guide any one data: my code error @ contract.methods.transfer(account2, web3.utils.fromWei(web3.utils.toBN(200), 'ether')).encodeABI()

daniellucas01

@daniellucas01

Hi guys

Sorry to disturb you guys

But i am new to web3j

And when deploying the code to the rinkeby test net using web3j and infura

The transaction always timed out for my android application

To be specific i am using web3j 4.2.0 for android , web3j cli version 4.2.0 and solc compiler version 0.4.25+commit.59dbf8f1.Windows.msvc to generate the abi and bin files

But no matter what i do whether its contract deployment or contract loading it always does not work for me

For contract deployment its always transaction forever pending (even when i alter the gas price and limit often) or contract deployed by remix cannot be loaded by web3j

Can someone help me ?

Craig Williams

@craigwilliams84

Hey Web3j team! Craig here, formerly of Kauri/ConsenSys...I work for Argent now.

Is the Epirus cli jar available in a public maven repository at all? We used to pull the web3j-console jar and execute org.web3j.console.Runner from within our build.gradle to generate the smart contract wrappers, but we have to now upgrade to the latest web3j for abiv2 support which means we'll have to change to the Epirus cli.

Craig Williams

@craigwilliams84

Figured out I could just use the codegen package and bypass the cli...all good!

Hope you're all doing well anyway!

Evan Saulpaugh

@esaulpaugh

@craigwilliams84 depending on your use case, https://github.com/esaulpaugh/headlong may be simpler

ligi

@ligi

which module includes WebSocketService? It does not seem to be in core

and I think it should go to the documentation as it is referenced here: https://docs.web3j.io/getting_started/ but the module import there does not import it

or was it renamed?

maybe @kunalbarchha knows as it is for his issue here: ethereum/go-ethereum#21386

Rok Povšič

@rok-povsic_gitlab

hello, when calling smart contract wrapper's method, how do I pass in funds? the method I want to call requires a msg.value field, i.e. the funds, but I can't find any reference on how to pass this in when calling the wrapper's method (i.e. I do contract.method(...).send() and the msg.value sent is 0)

Rok Povšič

@rok-povsic_gitlab

looks like this isn't possible looking at the wrapper source code. what I've done is inherited the wrapper class and simply copy-pasted the method I'm using, but replaced the executeRemoteCallTransaction to use the second parameter - which is the WEI value

Ivaylo Kirilov

@iikirilov

@ligi WebSocketService is in fact in the core module

@craigwilliams84 you probably should be using the web3j-gradle-plugin to generate the smart-contract wrappers https://github.com/web3j/web3j-gradle-plugin

@rok-povsic_gitlab can you provide the abi for that function

ligi

@ligi

@iikirilov ah thanks - I was on an old version 3.x - that was the reason - thanks for the pointer

Ivaylo Kirilov

@iikirilov

@dobesthosting_twitter the denomination is in wei - check out https://www.investopedia.com/terms/g/gwei-ethereum.asp

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