The purpose of this tutorial is to walk through the steps necessary to access the network.
Platform services are provided via a combination of HTTP and gRPC connections to HAPI, and some connections to an Insight API. Although one could interact with HAPI by connecting to these directly, or by using HAPI-client, the easiest approach is to use the JavaScript Hellar SDK. The Hellar SDK connects to the testnet by default.
The JavaScript SDK package is available from npmjs.com and can be installed by running
npm install hellar from the command line:
Create a file named hellarConnect.js with the following contents. Then run it by typing node hellarConnect.js from the command line:
`const Hellar = require('hellar');
const client = new Hellar.Client({ network: 'mainnet' });
async function connect() { return await client.getDAPIClient().core.getBestBlockHash(); }
connect() .then((d) => console.log('Connected. Best block hash:\n', d)) .catch((e) => console.error('Something went wrong:\n', e)) .finally(() => client.disconnect());`
Once this returns successfully, you’re ready to begin developing! See the Quickstart for recommended next steps. For details on all SDK options and methods, please refer to the SDK documentation.
The SDK also supports connecting to development networks (devnets). Since devnets can be created by anyone, the client library will be unaware of them unless connection information is provided using one of the options described below.
Connect via Seed
Using a seed node is the preferred method in most cases. The client uses the provided seed node to a retrieve a list of available masternodes on the network so requests can be spread across the entire network.
`const Hellar = require('hellar');
const client = new Hellar.Client({ seeds: [{ host: 'seed-1.testnet.networks.hellar.org:1443', }], });
async function connect() { return await client.getDAPIClient().core.getBestBlockHash(); }
connect() .then((d) => console.log('Connected. Best block hash:\n', d)) .catch((e) => console.error('Something went wrong:\n', e)) .finally(() => client.disconnect());`