Linked Questions

3 votes
0 answers
781 views

Can you make HTTP calls with Solidity? [duplicate]

I want to create a very close to random number generator for a smart contract which I would like to do HTTP calls to webservices to do. Is that able to be done with Solidity? I am just digging into ...
Anthony's user avatar
  • 183
107 votes
7 answers
37k views

How can an Ethereum contract get data from a website?

What is the process/workflow behind the process where an Ethereum contract gets some data from a website?
Dawny33's user avatar
  • 1,997
19 votes
2 answers
4k views

What advantages and disadvantages does Open Blockchain / Hyperledger / Fabric have over Ethereum?

Similar to this question about Ethereum and Bitcoin: What advantages and disadvantages does Open Blockchain (OBC) have over Ethereum? What can you do with OBC that you simply cannot with Ethereum? ...
eth's user avatar
  • 86.2k
12 votes
2 answers
4k views

Why do smart contract languages need to be deterministic?

I read somewhere that smart contract languages need to be deterministic. Why?
Satoshi Nakanishi's user avatar
12 votes
1 answer
5k views

What is a blockchain oracle?

What is a blockchain oracle for smart contracts? And why is it needed? I've seen a lot of posts about "how do oracles work", and "what is the oracle problem" but I don't understand ...
Keenan Olsen's user avatar
13 votes
3 answers
2k views

Smart contract consensus for dummies

I've read a few other questions/answers on smart contract consensus by nodes in the network, but I still don't understand the steps. Here's how I picture it: Two parties might agree upon a smart ...
John R.'s user avatar
  • 151
9 votes
3 answers
2k views

Reading Ethereum contract state variables

Is this assumption correct ? There is absolutely no way an ethereum contract can send data to the external world. It can only modify its state variables (later stored in the new block)and send ...
RajCherla's user avatar
  • 131
5 votes
2 answers
7k views

Is there a way to get the *current* price of ETH in solidity function?

Is it possible to get the current price of ETH in USD in a buyTokens function of a deployed solidity smart contract? For instance, every time GETH starts up is determines the price of ETH during ...
wardsback's user avatar
  • 399
3 votes
2 answers
893 views

Can you make ajax requests in a Dapp?

Mist recently launched its Beta (0.8.0), you can call any website for getting the HTML and JS files. What happens if inside my Dapp I make a XMLHttpRequest?
Fernando Tiberti's user avatar
7 votes
2 answers
724 views

Is it possible to invalidate a smart contract?

How can I invalidate a smart contract that has already been deployed? I might want to do so because of business reasons, and maybe beneficial network effects. Is it possible to invalidate a smart ...
niksmac's user avatar
  • 9,683
1 vote
1 answer
1k views

How to make an API call in solidity using Chainlink?

I am following the documentation from the Chainlink site, and I am attempting to make an API call. The main issue is I'm not sure what "address" is referring too. I am using remix in solidity v0.6 ...
Xin Ming's user avatar
5 votes
1 answer
384 views

Can you interact with other blockchains' tokens by using an Ethereum smart-contract?

Let's say that a dev has a public and private key of an address on another blockchain. He wants to create a smart-contract that can interacts with these coins, for moving them, for selling them, etc. ...
Henri Lils's user avatar
1 vote
1 answer
511 views

How can I build a smart Oracle of my own for a smart contract? [closed]

I need my smart contract to access data from some source. I want to build a smart Oracle in order to achieve this.
Arrow's user avatar
  • 11
1 vote
2 answers
812 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 ...
Dmitrii Vinokurov's user avatar
1 vote
1 answer
364 views

How do you handle a non-deterministic change during smart contract execution?

I read the following E-SO post and also several threads on Ethereum/Solidity forums regarding smart contracts and external servers (anything involving a socket): Why can't contracts make API ...
Robert Oschler's user avatar

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