Trending questions in Blockchain

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1 answer

How to allow request from host machine and deny from other machine, using ethereum in docker?

You can restrict access to the port ...READ MORE

Oct 9, 2018 in Blockchain by Omkar
 • 69,180 points • 1,898 views
0 votes
1 answer

How do I compile a piece of Solidity Code using eris' javascript?

The easiest way to compile Solidity is ...READ MORE

Sep 27, 2018 in Blockchain by digger
 • 26,740 points • 2,407 views
0 votes
1 answer

Unable to unmarshal non-string into Go struct field SendTxArgs from of common.Address

Probably you should specify the default_account for client(sender address). In my ...READ MORE

Aug 28, 2018 in Blockchain by Johnathon
 • 9,090 points • 3,726 views
+2 votes
1 answer

Composer playground - issue on RHEL

Hey, Renu353. There could be more than ...READ MORE

Sep 24, 2018 in Blockchain by Omkar
 • 69,180 points • 2,446 views
0 votes
1 answer

How to connect to *coin RPC-Server with PHP

If you want to connect inside your ...READ MORE

Sep 12, 2018 in Blockchain by slayer
 • 29,370 points • 3,045 views
+5 votes
1 answer

What are the programming languages I should know to become a Blockchain Developer?

Well, what programming language you have to ...READ MORE

Sep 25, 2018 in Blockchain by digger
 • 26,740 points • 2,282 views
0 votes
1 answer

Why estimateGas always returns null or zero?

The Web3 API uses error first style callbacks. Your ...READ MORE

Sep 28, 2018 in Blockchain by digger
 • 26,740 points • 2,348 views
0 votes
1 answer

Bitcoin Wallet address validation using Json and bitcoin/blockexplorer.

The URL isn't returning JSON. So instead ...READ MORE

Aug 20, 2018 in Blockchain by slayer
 • 29,370 points • 4,013 views
0 votes
1 answer

'Invalid sender' error after upgrading to geth 1.4.0

Guessing that the JSON RPC stuff changed ...READ MORE

Sep 11, 2018 in Blockchain by Christine
 • 15,750 points • 3,061 views
+1 vote
2 answers

Hex to ASCII conversion shows wrong result.

Hey, I use the following code: public static ...READ MORE

Aug 21, 2018 in Blockchain by Omkar
 • 69,180 points • 3,879 views
0 votes
1 answer

How to make a class that fits Blockchain.info Json?

Hey, I found a simple solution for ...READ MORE

Sep 18, 2018 in Blockchain by digger
 • 26,740 points • 2,744 views
0 votes
2 answers

Truffle migrate Error after run testrpc

Simple Solution: // module.exports = { // ...READ MORE

Sep 24, 2018 in Blockchain by Wasim
 • 2,421 views
0 votes
1 answer

How to create light wallet in Web3J?

You can use this method to create ...READ MORE

Aug 10, 2018 in Blockchain by slayer
 • 29,370 points • 4,403 views
+3 votes
1 answer

What is the difference between online and offline hyperledger composer?

Hey @Renu353! Well, it's good that you ...READ MORE

Sep 21, 2018 in Blockchain by Omkar
 • 69,180 points • 2,462 views
0 votes
1 answer

XMLHttpRequest is not defined while sending request to blockchain service via C#

use post data in url link and ...READ MORE

Sep 20, 2018 in Blockchain by slayer
 • 29,370 points • 2,620 views
0 votes
2 answers

Why is network already up to date while trying to deploy a contract on truffle?

I guess you have ganache running already ...READ MORE

Apr 24, 2018 in Blockchain by Shashank
 • 10,400 points • 6,624 views
0 votes
1 answer

Why is (startingBalance - endBalance) > (gasUsed * gasPrice) for an Ethereum transaction?

startingBalance and endBalance are BigNumber objects. Change ...READ MORE

Oct 1, 2018 in Blockchain by digger
 • 26,740 points • 2,131 views
0 votes
1 answer

Can't send transaction even if I use an example from official Ethereum webpage

As I understand your question you are ...READ MORE

Sep 21, 2018 in Blockchain by slayer
 • 29,370 points • 2,559 views
0 votes
1 answer

I am not able to change array elements globally

Remove the constant modifier from getArray(). constant functions do not write state ...READ MORE

Oct 9, 2018 in Blockchain by Omkar
 • 69,180 points • 1,771 views
0 votes
1 answer

How to solve “The method personal_newAccount does not exist/is not available” Error?

You are connecting using WS but have ...READ MORE

Jul 27, 2018 in Blockchain by slayer
 • 29,370 points • 4,965 views
0 votes
1 answer

How to choose which function is called first in Node Js

You can do something like: infuraProvider.getBlockNumber().then(function(blockNumber) { ...READ MORE

Oct 8, 2018 in Blockchain by Omkar
 • 69,180 points • 1,799 views
0 votes
1 answer

Creating an account with web3.js v0.2.6

The answer is let a=web3.personal.newAccount('!@superpassword') H ...READ MORE

Oct 9, 2018 in Blockchain by Omkar
 • 69,180 points • 1,753 views
0 votes
1 answer

Corda: uploading a file, attach and download

Hey, i found an example that i ...READ MORE

Sep 19, 2018 in Blockchain by digger
 • 26,740 points • 2,615 views
0 votes
1 answer

Calling functions from other contracts solidity

This code worked for me: pragma solidity ^0.4.2; contract ...READ MORE

Sep 17, 2018 in Blockchain by digger
 • 26,740 points • 2,698 views
0 votes
1 answer

Php code to generate Ethereum wallets.

You can use web3.eth.accounts in web3js web3.eth.accounts.create(); With Php, ...READ MORE

Jul 27, 2018 in Blockchain by slayer
 • 29,370 points • 4,932 views
0 votes
1 answer

Why Gas Used By Txn is different when invoking the same function in the same smart contract？

The input data might be different, but ...READ MORE

Sep 25, 2018 in Blockchain by Christine
 • 15,750 points • 2,336 views
0 votes
1 answer

Transfer the gas value of contract to my own address

Works fine for me: pragma solidity ^0.4.0; contract Test ...READ MORE

Oct 10, 2018 in Blockchain by Omkar
 • 69,180 points • 1,657 views
0 votes
1 answer

Can't install pyethereum module

The module's name is ethereum, not pyethereum. Using the ...READ MORE

Sep 27, 2018 in Blockchain by slayer
 • 29,370 points • 2,218 views
0 votes
1 answer

Error when Installing Ethereum: Package 'ethereum' has no installation candidate

It seems that there is a compatibility ...READ MORE

Oct 3, 2018 in Blockchain by digger
 • 26,740 points • 1,957 views
0 votes
1 answer

Solidity, javascript Wrong format: invalid address

The contract lacks initialization, at first. var contract ...READ MORE

Sep 17, 2018 in Blockchain by digger
 • 26,740 points • 2,637 views
0 votes
1 answer

Web3 ethereum miner_start not implemented.

You have to first enable "miner" API ...READ MORE

Aug 24, 2018 in Blockchain by digger
 • 26,740 points • 3,676 views
+1 vote
1 answer

Deploy contract using solcjs

Try to add some typo and run ...READ MORE

Sep 26, 2018 in Blockchain by slayer
 • 29,370 points • 2,202 views
0 votes
1 answer

How to register a user in Hyperledger Fabric?

Best practice would be to leverage an ...READ MORE

Sep 5, 2018 in Blockchain by Christine
 • 15,750 points • 3,144 views
0 votes
1 answer

How to create an asset on Bigchaindb server using http call

You could start like this: method = POST URL ...READ MORE

Sep 19, 2018 in Blockchain by Christine
 • 15,750 points • 2,538 views
0 votes
1 answer

Using Bitcoin's sendmany function with perl

Replace the line  my $action = $api->call('sendmany','',%recipients); with  my ...READ MORE

Sep 11, 2018 in Blockchain by digger
 • 26,740 points • 2,883 views
0 votes
1 answer

How to round a number down to 8 decimal places if its over 8 decimal places in Javascript

Try it in this way: function nrOfDecimals(number) { ...READ MORE

Sep 12, 2018 in Blockchain by slayer
 • 29,370 points • 2,839 views
0 votes
1 answer

Web3j: Writing operations on a contract always throw “java.lang.ArrayIndexOutOfBoundsException”

That exception is thrown when you pass ...READ MORE

Oct 1, 2018 in Blockchain by slayer
 • 29,370 points • 2,012 views
0 votes
1 answer

Access variables through auto-generated getters from a different contract

You just need to pass it in ...READ MORE

Oct 3, 2018 in Blockchain by slayer
 • 29,370 points • 1,925 views
0 votes
1 answer

Truffle migration error (test rpc is running)

1) Run the following command: npm install -g ...READ MORE

Oct 3, 2018 in Blockchain by slayer
 • 29,370 points • 1,925 views
0 votes
1 answer

“make” build ‘EC_GF2m_simple_method’ was not declared in this scope error in centos7

Step 1: I assume that your present ...READ MORE

Sep 17, 2018 in Blockchain by digger
 • 26,740 points • 2,592 views
0 votes
1 answer

What does _ mean in solidity language?

The _ symbol is a place holder. ...READ MORE

Aug 10, 2018 in Blockchain by digger
 • 26,740 points • 4,228 views
0 votes
1 answer

Contract deployment is raising gas issue while transaction and issue vary on various networksbl

Starting time can't be in the past. new ...READ MORE

Oct 3, 2018 in Blockchain by Omkar
 • 69,180 points • 1,877 views
0 votes
1 answer

How to interact with a Smart Contract on private network using Web3.js?

Once you set up infura you can ...READ MORE

Aug 22, 2018 in Blockchain by Christine
 • 15,750 points • 3,719 views
0 votes
1 answer

Getting wrong result from SHA256 than what is expected

It's just an encoding issue - don't ...READ MORE

Sep 6, 2018 in Blockchain by digger
 • 26,740 points • 3,035 views
0 votes
1 answer

Repeating transactions hangs - web3js, local geth

If you are sending transactions back-to-back from ...READ MORE

Sep 24, 2018 in Blockchain by digger
 • 26,740 points • 2,254 views
0 votes
1 answer

Testrpc Error: listen EADDRINUSE :::8545 on Mac

Another process is already using the port ...READ MORE

Sep 26, 2018 in Blockchain by digger
 • 26,740 points • 2,169 views
0 votes
1 answer

Nodejs Express: Getting different output in console.log and callback

If your getOrderStatus() function is like this: function getOrderStatus(_orderId, callback) ...READ MORE

Oct 9, 2018 in Blockchain by Omkar
 • 69,180 points • 1,598 views
0 votes
1 answer

Unable to enroll user in new org

The thing is by default, fabric-ca only has ...READ MORE

Aug 25, 2018 in Blockchain by Christine
 • 15,750 points • 3,537 views
0 votes
2 answers

Does Ethereum Solidity support Associative Arrays?

Here's a little example that passes values ...READ MORE

Sep 17, 2018 in Blockchain by Bobin
 • 2,527 views
0 votes
2 answers

Issues while installing Hyperledger Composer

Follow these steps to correctly install: mkdir ~/fabric-dev-servers ...READ MORE

Nov 15, 2018 in Blockchain by Omkar
 • 69,180 points • 2,521 views
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