BlockNap Oracle Server

Version 0.1.0

1.Create account in https://infura.io/

2.Create wallet in https://www.myetherwallet.com/

3.Get ether in http://faucet.ropsten.be:3001/

4.Clone repository.

5.Install nodeJS libraries. Execute "npm install" in folder.

6.Edit configuration file

• ADDRESS_WALLET = Address of wallet create
• PRIVATE_KEY_WALLET = Private key of wallet
• PRIVATE_KEY_INFURA = Private key of infura

	{
	  "account": "ADDRESS_WALLET",
	  "port": 8888,
	  "private": "PRIVATE_KEY_WALLET",
	  "oracleFile": [
		{
		  "name": "httpWeather",
		  "file": "httpWeather.js",
		  "cron": "*/50 * * * * *",
		  "api": "https://api.openweathermap.org/data/2.5/weather?q=Madrid&appid=key_weather",
		  "temp":200
		}
	  ],
	  "provider_config": "PRIVATE_KEY_INFURA",
	  "provider":"infura_ropsten",
	  "gas": 21000,
	  "gasPrice": 1000000000,
	  "path_oracles":"../../oracle",
	  "db": "postgresql://root@localhost:26257/blocknap?sslmode=disable"
	}

7.Execute index.sh

Prerequisites

1. Install CockroachDB v2.0.6

https://www.cockroachlabs.com/docs/releases/v2.0.6.html

2. Create data base blocknap

3. Execute script create_table_oracle_address.sql

Call Oracle Server

• URL - URL http://ip_server:port/oracle/v1/add/name_oracle/address/

• Header: Content-Type:application/json

• Body (ABI of Smart Contract):

{
   "abi":"......"
}

Add new oracle

1. In folder oracle copy httpWeather.js with other name

2. Modify cron method callCron with the logic of oracle to call know when call the smart contract

exports.callCron = function () {
    //add logical oracle here
    try {
        //oracle to call http
        request(oracle.api, function (error, response, body) {
            var infoWeather = JSON.parse(body);
            if(executeSmartContract(infoWeather,oracle)) {
                if (global.allAddress.length != undefined && (global.allAddress.length != null && global.allAddress.length > 0)) {
                    for(i=0;i<global.allAddress.length;i++) {
                        var address = global.allAddress[i]
                        if(checkAddress(address)) {
                            callSmartContract(address.address,address.abi);
                        }
                    }
                }
            }
            console.log('> error request ', error); // Print the error if one occurred
            console.log('> statusCode request ', response && response.statusCode); // Print the response status code if a response was received
            console.log('> body request:', body); // Print the HTML for the Google homepage.
        });
    }
    catch(err) {
        console.log("> error call request "+err);
    }
}

3. Modify method callSmartContract where you call the method or methods of the smart contract

//call smart contract
function callSmartContract(address, abi)  {

    console.log("> call address:"+address+" abi:"+abi);
    var overrideOptions = {
        gasLimit: global.properties.gas,
        gasPrice: global.properties.gasPrice,
        nonce: 0,
        value: ethers.utils.parseEther('1.0')
    };

    var abi2 = JSON.parse(abi);
    var contract = new ethers.Contract(address,abi2.abi.abi , global.wallet);

    //var callPromise = contract.getFecha(overrideOptions);
    var callPromise = contract.getFecha();
    callPromise.then(function(value) {
        console.log("> call "+address+' Single Return Value :' + JSON.stringify(value));
        console.log("> info "+address+" - "+utils.toUtf8String(value.data));
    });

}

4. Add oracle to properties in section oracleFile (3 mandatory and the rest as developer needs)

	{
		  "name": "<nameToCallFromManager>",
		  "file": "<nameNewFileJSOfOracle>",
			"cron": "<cron condition as usual>"
		}

5. Restart server