Trending questions in Blockchain

+1 vote
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what is use of msg.sender in solidity code?

msg.sender(address) function indicated the sender of the ...READ MORE

Apr 25, 2018 in Blockchain by Shashank
• 10,400 points
9,407 views
0 votes
1 answer

Error using EtherJS: this.provider.getTransactionCount is not a function

With this line it should work fine: wallet.provider ...READ MORE

Sep 26, 2018 in Blockchain by digger
• 26,740 points
2,770 views
0 votes
1 answer

Access multiple return values (a, b, c) from solidity function in web3js

You'll get an array of return values ...READ MORE

Sep 14, 2018 in Blockchain by slayer
• 29,370 points
3,288 views
0 votes
1 answer

Ethereum: functions Burn and Transfer source

This statement is used to publish an event that ...READ MORE

Oct 9, 2018 in Blockchain by Omkar
• 69,220 points
2,204 views
0 votes
1 answer

Hyperledger fabcar: node enrollAdmin.js error

Update the node: npm rebuild and then run ...READ MORE

Oct 26, 2018 in Blockchain by anonymous
1,420 views
0 votes
1 answer

Hyperledger Composer: How to query using string?

You can try this: query selectReading { ...READ MORE

Nov 9, 2018 in Blockchain by Omkar
• 69,220 points
815 views
0 votes
1 answer

Hyperledger Farbic: Deploying business network definition

Try to clean everything using the below ...READ MORE

Nov 13, 2018 in Blockchain by Omkar
• 69,220 points
619 views
0 votes
1 answer

Hyperledger Composer: Not able to query fabric.

Add another rule to .acl file to ...READ MORE

Nov 12, 2018 in Blockchain by Omkar
• 69,220 points
660 views
0 votes
1 answer

Ethereum, web3, Error: invalid argument 0: cannot unmarshal non-string as hex data, when I call a contract

I have the same problem. But with ...READ MORE

Oct 8, 2018 in Blockchain by Omkar
• 69,220 points
2,170 views
0 votes
1 answer

Uncaught ReferenceError: web3 is not defined at window.onload

I think the onload is giving the issue. Try this ...READ MORE

Sep 28, 2018 in Blockchain by slayer
• 29,370 points
2,585 views
0 votes
1 answer

Hyperledger Composer: Failed to load connector module “composer-connector-undefined” for connection type “undefined”

Hey. First, make sure that you are extending ...READ MORE

Oct 30, 2018 in Blockchain by Omkar
• 69,220 points
1,199 views
+1 vote
1 answer

Getting Hash160 bitcoin address in python

There is a package to decode and ...READ MORE

Aug 24, 2018 in Blockchain by slayer
• 29,370 points
4,047 views
0 votes
1 answer

Stuck while using call_back_address and ipn url in coinpayment.net gateway

To make use of this api, just ...READ MORE

Aug 31, 2018 in Blockchain by digger
• 26,740 points
3,776 views
0 votes
1 answer

Ethereum solidity: Unable to get value from another contract

I have faced similar issues when compiling ...READ MORE

Oct 15, 2018 in Blockchain by Omkar
• 69,220 points
1,803 views
0 votes
1 answer

Hyperledger Fabric: Not able to install docker

Clean up the invalid package repository: cd ../../etc/apt/sources.list.d sudo ...READ MORE

Nov 2, 2018 in Blockchain by Omkar
• 69,220 points
1,021 views
0 votes
1 answer

Hyperledger fabric: Unable to query result

In Hyperledger Fabric v1.0.0 your chaincode should confirm ...READ MORE

Oct 30, 2018 in Blockchain by Omkar
• 69,220 points
1,143 views
0 votes
1 answer

NodeJS POST Request Over JSON-RPC

You're missing the --header option: curl --request POST \ ...READ MORE

Sep 28, 2018 in Blockchain by digger
• 26,740 points
2,512 views
0 votes
1 answer

Setting up Hyperledger Fabric Application with IBM Cloud.

You have to develop your "Client" application ...READ MORE

Nov 6, 2018 in Blockchain by Perry
• 17,100 points
806 views
0 votes
1 answer

What is the default network that truffle migrates to when the config has 2 networks?

If --network is unspecified, it deploys to only development. You ...READ MORE

Oct 15, 2018 in Blockchain by Omkar
• 69,220 points
1,759 views
0 votes
1 answer

Get specific JSON data value using array from Coin Market Cap API

use inArray function. example: $.getJSON("//api.coinmarketcap.com/v1/ticker/?limit=0", function(data) { ...READ MORE

Oct 8, 2018 in Blockchain by Omkar
• 69,220 points
2,052 views
0 votes
1 answer

Ethereum truffle MetaCoin : 'intrinsic gas too low' error

Change the genesis block gasLimit to "gasLimit": "0x2FEFD800", config ...READ MORE

Oct 22, 2018 in Blockchain by Omkar
• 69,220 points
1,440 views
0 votes
1 answer

HyperLedger Composer: Failed to load connector module “composer-connector-embedded” for connection profile “testprofile”

First, update your devDependencies in package.json "devDependencies": { ... "composer-admin": ...READ MORE

Nov 2, 2018 in Blockchain by Omkar
• 69,220 points
960 views
0 votes
1 answer

Solidity: logical AND outputs parser error

Its Syntax error logical and operator is ...READ MORE

Oct 12, 2018 in Blockchain by Perry
• 17,100 points
1,833 views
0 votes
1 answer

Can I execute distributions in ERC20 tokens on a later stage?

It is best to have a claim ...READ MORE

Nov 2, 2018 in Blockchain by Prerna
• 1,960 points
927 views
0 votes
1 answer

var_dump of a JSON response returns NULL

You should be aware of the chances ...READ MORE

Aug 28, 2018 in Blockchain by digger
• 26,740 points
3,781 views
0 votes
1 answer

Truffle migrate fails due to missing function, but it exists in node_modules

deployer.deploy(password1, password2, deadline, {value: 100, from: accounts[0]}); ...READ MORE

Oct 3, 2018 in Blockchain by digger
• 26,740 points
2,214 views
0 votes
1 answer

Hyperledger Fabric: cannot run chaincode from github on Ubuntu terminal

Like the error says: *SimpleChaincode does not implement ...READ MORE

Oct 31, 2018 in Blockchain by Omkar
• 69,220 points
1,002 views
+3 votes
1 answer

When I ran truffle init, I got this error:

Hey there @Davidala! The error says that it ...READ MORE

Oct 29, 2018 in Blockchain by Omkar
• 69,220 points
955 views
0 votes
2 answers

How do I interact with a smart contract on a private network through web3.js

I found a blog that explains how ...READ MORE

Aug 20, 2018 in Blockchain by slayer
• 29,370 points
4,114 views
0 votes
1 answer

Can one contract own tokens of another contract?

Yes, contracts can own tokens. The transaction you ...READ MORE

Oct 17, 2018 in Blockchain by Christine
• 15,790 points
1,581 views
0 votes
1 answer

Hyperledger composer: network start gives no output

You are using -v as your option ...READ MORE

Nov 5, 2018 in Blockchain by Omkar
• 69,220 points
740 views
0 votes
1 answer

Solidity geth: Error encountered during contract execution [Bad instruction]

recipes is a dynamic storage array. You need ...READ MORE

Oct 15, 2018 in Blockchain by Omkar
• 69,220 points
1,632 views
0 votes
1 answer

Hyperledger fabric: curl not working to invoke chaincode

Hyperledger Fabric does not offer a REST ...READ MORE

Oct 23, 2018 in Blockchain by Perry
• 17,100 points
1,267 views
0 votes
1 answer

How to issue regular payouts to multiple wallets?

The cheapest way to do this is ...READ MORE

Oct 30, 2018 in Blockchain by Christine
• 15,790 points
989 views
0 votes
1 answer

Hyperledger Fabric: build error "files are missing SPDX-License-Identifier headers"

Try this: make peer orderer peer-docker orderer-docker tools-docker ...READ MORE

Oct 30, 2018 in Blockchain by Omkar
• 69,220 points
955 views
0 votes
1 answer

Ethereum Mist: Compiling Error with sha3

First run: npm install sha3 and then sudo ...READ MORE

Oct 24, 2018 in Blockchain by Omkar
• 69,220 points
1,214 views
0 votes
1 answer

Ethereum call contract method that emits an event, from another contract

You need to refer to the EventEmitter by ...READ MORE

Sep 25, 2018 in Blockchain by digger
• 26,740 points
2,452 views
0 votes
1 answer

Ethereum client-go RPC response 403 “invalid host specified”

Adding --rpcvhosts=* should solve the issue READ MORE

Oct 1, 2018 in Blockchain by slayer
• 29,370 points
2,177 views
0 votes
1 answer

Hyperledger Fabric: How to retrieve success payload via nodejs client?

The channel.sendTransactionProposal generates a Response object You ...READ MORE

Oct 30, 2018 in Blockchain by Omkar
• 69,220 points
919 views
0 votes
1 answer

How to reduce a random hash to a boolean value

Take the largest or smallest bit from ...READ MORE

Oct 30, 2018 in Blockchain by Christine
• 15,790 points
1,005 views
0 votes
1 answer

HyperledgerFabric : *SampleChaincode does not implement shim.Chaincode error

The reason you are getting this error ...READ MORE

Oct 29, 2018 in Blockchain by Omkar
• 69,220 points
948 views
0 votes
1 answer

Cant get a specific value in JSON/PHP

Convert the json-string to a php-array and ...READ MORE

Sep 11, 2018 in Blockchain by slayer
• 29,370 points
3,023 views
0 votes
3 answers

python ethereum (pyethapp): Failed building wheel for scrypt.

First try installing sudo apt-get install openssl However, If ...READ MORE

Oct 12, 2018 in Blockchain by Girish
1,922 views
0 votes
1 answer

Etheruem: Unable to import library in Remix IDE

Your link is broken. This is the ...READ MORE

Oct 9, 2018 in Blockchain by Omkar
• 69,220 points
1,801 views
0 votes
2 answers

UnicodeDecodeError: 'utf-8' codec can't decode byte (python)

I found a python rpc library for ...READ MORE

Sep 4, 2018 in Blockchain by Piston
3,264 views
0 votes
1 answer

Hyperledger Composer: How to save deployments?

You are losing your deployments probably because ...READ MORE

Oct 29, 2018 in Blockchain by Omkar
• 69,220 points
919 views
0 votes
1 answer

Hyperledger Fabric: ./byfn.sh -m up failed

Try adding GODEBUG=netdns=go to the environment variables ...READ MORE

Oct 26, 2018 in Blockchain by Omkar
• 69,220 points
1,048 views
0 votes
1 answer

UnhandledPromiseRejectionWarning: Insufficient funds error in Ethereum: NodeJS web3

sendSignedTransaction returns a promiEvent onto which you can chain then and catch: web3.eth.sendSignedTransaction('0x' + ...READ MORE

Oct 15, 2018 in Blockchain by Omkar
• 69,220 points
1,518 views
+11 votes
4 answers

How do I create an ether wallet?

The Ethereum Wallet is a gateway to decentralized applications ...READ MORE

Sep 14, 2018 in Blockchain by Shiva
2,329 views
0 votes
1 answer

Are Ethereum contract function securable?

The reason is that you are using ...READ MORE

Oct 30, 2018 in Blockchain by Christine
• 15,790 points
933 views