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I have gone through the docs of ethereum and truffle as well. I had created a contract for more understanding related to contracts and its compilation and deployment on local network.

But I have specific requirement that I want to fetch some sort of data from blockchain public network and want to display it on website and generate reports based on that data.

How can I get the use data from 3rd party contract. Please refer below example to understand the scenario.

So, how this can be done w/o creating a contract ?

Eg. I want to get latest NASDAQ share price ups and downs of the current day and want to generate a chart dynamically on website.

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  • Above link is related to pulling data from website to contract, but my question is to pull data from blockchain network to website.
    – Bhavik
    Commented Nov 29, 2017 at 7:34
  • could you give more information? What kind of info you want from the blockchain? Last block number? gas price? Commented Nov 29, 2017 at 11:10
  • For Eg. You have created one contract in which you are storing/maintaining latest public share prices for the day. So I want those prices from you. As there is a concept of Gas price which I need to pay you while I am using your services, but I am stuck here that how I would make a call to your services/contract methods.
    – Bhavik
    Commented Nov 30, 2017 at 3:17

1 Answer 1

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So this really depends on the contract, if the contract implemented a public method or a public state variable then it's possible for you to get the data.

contract SimpleFetch {
    uint public fixedData = 12345;

    function get() public constant returns (uint) {
      return 12345;
    }

    function balanceOf(address _owner) constant returns (uint balance) {
      return 1;
    }
  }

The above variables and functions could be called by anyone. You mentioned stock prices, so I put the balanceOf as an example there because all erc20 tokens implement this. And it is something you can call.

play with it yourself in a fiddle: https://ethfiddle.com/ZWww_YXa-3

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  • It is correct that when data member is public then I can use that. But with what medium, I mean using ABI to access those methods OR else any other source of communication.
    – Bhavik
    Commented Nov 30, 2017 at 9:22
  • of course you need to know the interface of the contract. that is the whole point of ERC20, so that the token interface is known without needing to manually find out
    – cappy
    Commented Dec 3, 2017 at 7:59

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