Connecting to the Network

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Connect from JavaScript

Here is the boilerplate and a minimal starter example that connects to the XBR Network from JavaScript in a browser with MetaMask using Web3.js, and checks the ETH and XBR balances of the primary account:

// app entry point
window.addEventListener('load', function () {
    unlock_metamask();
});

// check for MetaMask and ask user to grant access to accounts ..
// https://medium.com/metamask/https-medium-com-metamask-breaking-change-injecting-web3-7722797916a8
async function unlock_metamask () {
    if (window.ethereum) {
        // if we have MetaMask, ask user for access
        await ethereum.enable();

        // instantiate Web3 from MetaMask as provider
        window.web3 = new Web3(ethereum);
        console.log('ok, user granted access to MetaMask accounts');

        // set new provider on XBR library
        xbr.setProvider(window.web3.currentProvider);
        console.log('library versions: web3="' + web3.version.api + '", xbr="' + xbr.version + '"');

        // now enter main ..
        await main(web3.eth.accounts[0]);

    } else {
        // no MetaMask (or other modern Ethereum integrated browser) .. redirect
        var win = window.open('https://metamask.io/', '_blank');
        if (win) {
            win.focus();
        }
    }
}

The important step is to set the Web3 provider on the XBR library with xbr.setProvider(web3.currentProvider).

Above will jump into main() when the user has granted access. Here is an example where we ask for the current XBR balance of the user account, and the XBR Network membership level:

// main app: this runs with the 1st MetaMask account (given the user has granted access)
async function main (account) {
    console.log('starting main from account ' + account);

    // ask for current balance in XBR
    var balance = await xbr.xbrToken.balanceOf(account);
    if (balance > 0) {
        balance = balance / 10**18;
        console.log('account holds ' + balance + ' XBR');
    } else {
        console.log('account does not hold XBR currently');
    }
}

You can download the complete example page with above code from here.

When opening this Web page (remember, it needs to served from a Web server, file:// will not work), you should see log output like the following in your browser console:

ok, user granted access to MetaMask accounts
xbr_app1.html:30 library versions: web3="0.20.3", xbr="18.11.1"
xbr_app1.html:46 starting main from account 0x90f8bf6a479f320ead074411a4b0e7944ea8c9c1
xbr_app1.html:52 account holds 1000000000 XBR
xbr_app1.html:60 account is already member in the XBR network (level=2)

Connect from Python

Here is the boilerplate and a minimal starter example that connects to the XBR Network from Python using Web3.py, and checks the ETH and XBR balances of the primary account:

import sys
import web3
import xbr


def main (account):
    print('using account address {}'.format(account))

    balance_eth = w3.eth.getBalance(account)
    balance_xbr = xbr.xbrToken.functions.balanceOf(account).call()

    print('current balances: {} ETH, {} XBR'.format(balance_eth, balance_xbr))


if __name__ == '__main__':
    print('using web3.py v{}'.format(web3.__version__))

    # using automatic provider detection:
    from web3.auto import w3

    # check we are connected, and check network ID
    if not w3.isConnected():
        print('could not connect to Web3/Ethereum')
        sys.exit(1)
    else:
        print('connected to network {}'.format(w3.version.network))

    # set new provider on XBR library
    xbr.setProvider(w3)

    # now enter main ..
    main(w3.eth.accounts[0])

The important step is to set the Web3 provider on the XBR library with xbr.setProvider(w3).

Example output of above:

(cpy371_1) oberstet@thinkpad-x1:~/scm/xbr/xbr-protocol$ python teststack/test_client1.py
using web3.py v4.8.1
connected to network 5777
using account address 0x90F8bf6A479f320ead074411a4B0e7944Ea8c9C1
current balances: 992385178585000000000 ETH, 1000000000000000000000000000 XBR

Congratulations! You are now connected to the XBR Network.

Tip

Instead of relying on autodetecting the Web3 provider, one can also configure a provider explicitly, which allows to fine tune e.g. request timeouts:

provider = web3.Web3.HTTPProvider("http://127.0.0.1:8545", request_kwargs={'timeout': 5})
w3 = web3.Web3(provider)