NodeJS libraries for interfacing and integrating MonitorChain by subscribers.
Switch branches/tags
Nothing to show
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Permalink
Type Name Latest commit message Commit time
Failed to load latest commit information.
src
test
LICENSE.md
README.md
package.json

README.md

MonitorChain Interface Library

monitorchain-interface-library

NodeJS libraries for interfacing and integrating MonitorChain by subscribers.

Install

$ npm install monitorchain-interface-library

USAGE

Following modules are being exported by the library:

  • AccessInterface - the interface is providing the public and restricted-to-subscribers methods
  • Web3 - returns the web3 provider. The type of the provider is defined by the protocol type (web socket, http, ipc). If a 12 words mnemonic is passed - return the truffle-hdwallet-provider's instance
  • ERC20Interface - can be used for accessing the ERC20 tokens' standard methods (name, symbol, totalSupply, etc.)

It supports both promises and the async-await calls with or without the callbacks.

Examples

const {AccessInterface} = require('monitorchain-interface-library');
const log = console.log;

const mc = new AccessInterface(
    'http://main.infura.io/<API KEY>',
    '0xF8CE9D2....71337Bd6201a', //The MonitorChain address
    '12 words mnemonic is here'
);

// Get the list of supported tokens (resolve a promise)
mc.getAllSupportedTokens().then(console.log);

// Get number of the supported tokens (using a callback)
mc.getNumberSupportedTokens((err, result) => {console.log(err, result)})

// Calculate a subscription price (async-await syntax)
const calc = async () => {
    // 45-days subscription for 50 tokens
    const price = await mc.calculatePrice(45, 50);
    console.log(price);
};

calc();

// Subscribe to given list of tokens (default period)
const tokens = [
    "0xB8c77482e45F1F44dE1745F52C74426C631bDD52",
    "0xf230b790E05390FC8295F4d3F60332c93BEd42e2"
];

mc.subscribe(tokens, (err, result) => {
    console.log(`${err ? 'Fail':'Success'}`)
});

// 45 days subscription
let token = "0xE41d2489571d322189246DaFA5ebDe1F4699F498";
mc.subscribe([token], 45, (err, result) => {
 console.log(`${err ? 'Fail':'Success'}`)
});

// Add a token to subscription (30 days), remit 1 eth for further purposes
const weiPerEth = "1000000000000000000";
let newToken = "0xA4e8C3Ec456107eA67d3075bF9e3DF3A75823DB0";
mc.init().then(() => {
    mc.wallet = 1;  // use the second address from the 'addresses' array generated by the truffle hdwallet provider
    mc.addTokenToSubscription(newToken, null, null, weiPerEth, (err, result) => {
        console.log(`${err ? err:'Success'}`)
    })
});

Using a built-in truffle hdwallet provider

const {AccessInterface} = require('monitorchain-interface-library');
const log = console.log;

const mc = new AccessInterface(
    'http://localhost:8545',
    '0xF8CE9D27Ff65E59cc5499a44f3fd71337Bd6201a',
    '12 words mnemonic is here'
);

const subscribe = async() => {
    mc.wallet = 2;

    log(await mc.getSubscriptionData());
    log(await mc.getTokensSubscribedTo());

    await mc.subscribe([
        "0xB8c77482e45F1F44dE1745F52C74426C631bDD52"
    ]);

    log(await mc.getSubscriptionData());
    log(await mc.remainingSubscriptionDays());
    log(await mc.getTokensSubscribedTo());
};

subscribe();

Using a custom web3 instance

const {AccessInterface} = require('monitorchain-interface-library');
const HDWalletProvider = require('truffle-hdwallet-provider');
const Web3 = require('web3');

const nodeAddress =  'http://localhost:8545';
const monitorChainAddress = '0xF8CE9D27Ff65E59cc5499a44f3fd71337Bd6201a';
const mnemonic = '12 words mnemonic is here';

const web3 = new Web3(new HDWalletProvider(mnemonic, nodeAddress, 0, 20));

// A static method 'web3' allows to pass a custom web3 instance
const mc = AccessInterface.web3(web3, monitorChainAddress);

mc.getAllSupportedTokens(console.log);

Listening for realtime events

const {AccessInterface, ERC20Interface} = require('monitorchain-interface-library');
const log = console.log;
const monitorChainAddress = '0xF8CE9D27Ff65E59cc5499a44f3fd71337Bd6201a';


const mc = new AccessInterface(
    'http://localhost:8545',
    monitorChainAddress,
    '12 words mnemonic is here'
);

const ws = new AccessInterface(
    'ws://localhost:8543',
    monitorChainAddress
);

const callback = async (err, result) => {
    if(err) throw err;
    const tokenAddress = await mc.getTokenForEventId(result);
    if (!tokenAddress) return; // return if a customer is not subscribed to token

    log(`${tokenAddress}: a status has been changed: ${result}`);
    log(await mc.getCurrentStatusDetails(tokenAddress));
    const token =ERC20Interface.web3(mc.w3, tokenAddress);
    const tokenInfo = await token.tokenInfo();
    log(JSON.stringify(tokenInfo, null, 4));
};

ws.onTokenStatusChanged(callback);

Troubleshooting

Transactions are too slow

Increase a gas price:

const {ERC20Interface} = require('monitorchain-interface-library');
const token = new ERC20Interface(...);
...
token.gasPrice = 3; //gWei
...
Error: Exceeds block gas limit

Decrease the gasLimit:

const {ERC20Interface} = require('monitorchain-interface-library');
const token = new ERC20Interface(...);
...
token.gasLimit = '3000000'
...

Error: Cannot find module 'ethereumjs-wallet/hdkey'

$ npm uninstall ethereumjs-wallet
$ npm install ethereumjs-wallet@0.6.0

License

GPL-2.0