Trending questions in Blockchain

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1 answer

Hyperledger Composer: Error trying to instantiate composer runtime.

It looks like a problem with composer-cli.  A ...READ MORE

Oct 26, 2018 in Blockchain by Omkar
 • 69,190 points • 488 views
0 votes
1 answer

Hyperledger fabric: vagrant up in devenv fails

This is a problem with vagrant 1.9.3: You ...READ MORE

Oct 29, 2018 in Blockchain by Omkar
 • 69,190 points • 351 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
 • 69,190 points • 472 views
0 votes
2 answers

Modifiers in solidity

pragma solidity ^0.4.17; contract ModifiersTutorial { ...READ MORE

Oct 12, 2018 in Blockchain by Pulkit
 • 1,250 views
0 votes
1 answer

Converting 5e-08 to decimal in PHP

Use printf with the appropriate format specifier: printf("%.8f", 5 / ...READ MORE

Sep 12, 2018 in Blockchain by digger
 • 26,740 points • 2,346 views
0 votes
1 answer

Integrating web3 in cloud functions module

I had this issue and my problem ...READ MORE

Oct 17, 2018 in Blockchain by Perry
 • 17,100 points • 827 views
0 votes
1 answer

Hyperledger Composer cant find business card.

I changed the code to: var businessNetwork = ...READ MORE

Oct 26, 2018 in Blockchain by Omkar
 • 69,190 points • 434 views
0 votes
1 answer

Not able to invoke a contract in Ethereum Private chain using geth

Hope this helps: contract mortal { /* ...READ MORE

Oct 22, 2018 in Blockchain by Omkar
 • 69,190 points • 594 views
0 votes
1 answer

Nodejs cannot access Hyperledger composer shows error

1) you need Node 8.9.x or higher ...READ MORE

Oct 23, 2018 in Blockchain by Perry
 • 17,100 points • 531 views
0 votes
1 answer

Cant extract hyperledger artifacts

Simplify the PATH first. In a CMD, type: set PATH=C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\ set ...READ MORE

Oct 29, 2018 in Blockchain by Omkar
 • 69,190 points • 280 views
0 votes
1 answer

Unable to change a state variable in a contract

I am assuming that the issue is ...READ MORE

Oct 30, 2018 in Blockchain by Christine
 • 15,790 points • 237 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 • 1,676 views
0 votes
1 answer

Cant query in Hyperledger Composer

There's a mistake in your WHERE statement. ...READ MORE

Oct 26, 2018 in Blockchain by Omkar
 • 69,190 points • 371 views
0 votes
2 answers

Ethereum function completed not event not showing up

Oh ya. I was passing unit but ...READ MORE

Oct 24, 2018 in Blockchain by slayer
 • 29,350 points • 393 views
+1 vote
1 answer

Using bccsp instance from chaincode

You can take a look at this code snippet. ...READ MORE

Oct 22, 2018 in Blockchain by Christine
 • 15,790 points • 469 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 • 255 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 • 2,847 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
 • 29,350 points • 2,227 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 • 199 views
0 votes
1 answer

How to get value from solidity contract using java?

web3j caters for this very use case. It ...READ MORE

Sep 28, 2018 in Blockchain by slayer
 • 29,350 points • 1,483 views
0 votes
1 answer

Mining in private net: Balance not increasing

Use this command to start miner: miner.start() To stop ...READ MORE

Oct 24, 2018 in Blockchain by Omkar
 • 69,190 points • 357 views
0 votes
2 answers

Check Bitcoin Balance with mybitx api https GET url

You can use the PHP Requests library for an ...READ MORE

Sep 17, 2018 in Blockchain by Lalit
 • 2,024 views
0 votes
1 answer

How to install v1.7.3. of Geth using ppa?

geth package version v1.7.3 is only available on ubuntu zestyplatform i.e. ubuntu ...READ MORE

Oct 17, 2018 in Blockchain by Christine
 • 15,790 points • 649 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
 • 69,190 points • 980 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 • 1,229 views
0 votes
1 answer

How to read the ETH value and other token values from an account?

You can do this eth.accounts shows you all known ...READ MORE

Oct 22, 2018 in Blockchain by Omkar
 • 69,190 points • 372 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 • 2,601 views
0 votes
1 answer

Go ethereum: Gradle sync error

Try the below code : maven { ...READ MORE

Oct 24, 2018 in Blockchain by Omkar
 • 69,190 points • 247 views
0 votes
1 answer

Hyperledger Composer Incompatible versions error

The versions are same. Maybe its a ...READ MORE

Oct 24, 2018 in Blockchain by Omkar
 • 69,190 points • 246 views
0 votes
1 answer

Web-scraping from Coinbase with Python (Pycharm)

Data that you want to scrape is ...READ MORE

Sep 4, 2018 in Blockchain by digger
 • 26,740 points • 2,401 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
 • 29,350 points • 2,839 views
0 votes
1 answer

How to Check if string is in list in javascript?

At first, make sure that the string ...READ MORE

Sep 19, 2018 in Blockchain by slayer
 • 29,350 points • 1,750 views
0 votes
1 answer

Ethereum serpent version conflict error.

Upgrade to the lastest version of ethereum-serpent ...READ MORE

Oct 24, 2018 in Blockchain by Omkar
 • 69,190 points • 235 views
0 votes
1 answer

eth.getTransactionReceipt returns null

It looks like there's an issue with ...READ MORE

Sep 25, 2018 in Blockchain by slayer
 • 29,350 points • 1,488 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
 • 29,350 points • 1,226 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 • 1,485 views
0 votes
1 answer

re hyperledger's node/sdk: there is no typing definition( index.d.ts )

Looks like a bug in that the ...READ MORE

Oct 23, 2018 in Blockchain by Perry
 • 17,100 points • 262 views
0 votes
1 answer

Error when trying to deploy Ethereum smart contract using web3j

Create a new credential based on the Credentials.create ...READ MORE

Oct 3, 2018 in Blockchain by slayer
 • 29,350 points • 1,115 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
 • 957 views
0 votes
1 answer

truffle migrate Error

testrpc Check your truffle.js config port and ip ...READ MORE

Oct 8, 2018 in Blockchain by Omkar
 • 69,190 points • 883 views
0 votes
1 answer

How can I deploy a hyperledger business network using docker-compose?

If you want to use Composer, be ...READ MORE

Oct 4, 2018 in Blockchain by Perry
 • 17,100 points • 1,038 views
0 votes
1 answer

How to Query hdfs with Spark Sql

Yyou can achieve this by creating Dataframe. val ...READ MORE

Sep 20, 2018 in Blockchain by slayer
 • 29,350 points • 1,640 views
0 votes
1 answer

Test ethereum Event Logs with truffle

You are passing tx hash into done() ...READ MORE

Sep 21, 2018 in Blockchain by slayer
 • 29,350 points • 1,598 views
0 votes
1 answer

Is the msg.sender address changed while passing to another contract as a parameter?

I tried your contracts in Remix, but ...READ MORE

Oct 10, 2018 in Blockchain by Omkar
 • 69,190 points • 775 views
0 votes
1 answer

pubToAddress method from ethereumjs-util throws AssertionError: false == true

This code works fine: var keythereum = require('keythereum'); var ...READ MORE

Oct 8, 2018 in Blockchain by Omkar
 • 69,190 points • 856 views
0 votes
1 answer

Blockchain: Installing an earlier version of ethereum using apt-get on

geth does not make the previous version available ...READ MORE

Oct 10, 2018 in Blockchain by Omkar
 • 69,190 points • 755 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
 • 2,245 views
0 votes
1 answer

How to define the path to hyperledger-fabric chaincode?

You can find that in docker-compose files ...READ MORE

Oct 4, 2018 in Blockchain by Perry
 • 17,100 points • 969 views
0 votes
2 answers

Web socket API session automatically disconnecting

Yes, the code given by Christine works! ...READ MORE

Aug 29, 2018 in Blockchain by digger
 • 26,740 points • 2,483 views
+1 vote
3 answers

What is the pattern for handling throw on a Solidity contract in tests

In my opinion the cleanest way is: it("should ...READ MORE

Sep 25, 2018 in Blockchain by Lupin
 • 1,227 views
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