Resolving Domains in Web Applications

Resolution is a library for interacting with NFT domain names. It can be used to retrieve payment addresses, IPFS hashes for decentralized websites, and GunDB usernames for decentralized chat.

Resolution is built and maintained by Unstoppable Domains and supports decentralized domains across two main zones:

Installing Resolution

Resolution can be installed with either yarn or npm.

yarn add @unstoppabledomains/resolution

npm install @unstoppabledomains/resolution --save

If you're interested in resolving domains via the command line, see the CLI section below.

Using Resolution

Create a new project.

mkdir resolution && cd $_
yarn init -y
yarn add @unstoppabledomains/resolution

Look up a domain's crypto address

Create a new file in your project, address.js.

const { default: Resolution } = require('@unstoppabledomains/resolution');
const resolution = new Resolution();

function resolve(domain, currency) {
  resolution
    .addr(domain, currency)
    .then((address) => console.log(domain, 'resolves to', address))
    .catch(console.error);
}

function resolveMultiChain(domain, currency, chain) {
  resolution
    .multiChainAddr(domain, currency, chain)
    .then((address) => console.log(domain, 'resolves to', address, version))
    .catch(console.error);
}

resolve('brad.crypto', 'ETH');
resolve('brad.zil', 'ZIL');
resolveMultiChain('brad.crypto', 'USDT', 'ERC20');
resolveMultiChain('brad.crypto', 'USDT', 'OMNI');

Execute the script.

$ node address.js
brad.crypto resolves to 0x8aaD44321A86b170879d7A244c1e8d360c99DdA8
brad.zil resolves to zil1yu5u4hegy9v3xgluweg4en54zm8f8auwxu0xxj

Find the IPFS hash for a decentralized website

Create a new file in your project, ipfs_hash.js.

const { default: Resolution } = require('@unstoppabledomains/resolution');
const resolution = new Resolution();

function resolveIpfsHash(domain) {
  resolution
    .ipfsHash(domain)
    .then((hash) =>
      console.log(
        `You can access this website via a public IPFS gateway: https://gateway.ipfs.io/ipfs/${hash}`,
      ),
    )
    .catch(console.error);
}

resolveIpfsHash('homecakes.crypto');

Execute the script.

$ node ipfs_hash.js
You can access this website via a public IPFS gateway: https://gateway.ipfs.io/ipfs/QmVJ26hBrwwNAPVmLavEFXDUunNDXeFSeMPmHuPxKe6dJv

Find a custom record

Create a new file in your project, custom-resolution.js.

const { default: Resolution } = require('@unstoppabledomains/resolution');
const resolution = new Resolution();

function resolveCustomRecord(domain, record) {
  resolution
    .records(domain, [record])
    .then((value) => console.log(`Domain ${domain} ${record} is: ${value}`))
    .catch(console.error);
}

resolveCustomRecord('homecakes.crypto', 'custom.record.value');

Command Line Interface

To use resolution via the command line install the package globally.

yarn global add @unstoppabledomains/resolution

npm install -g @unstoppabledomains/resolution

By default, the CLI uses Infura as its primary gateway to the Ethereum blockchain. If you'd like to override this default and set another provider you can do so using the --ethereum-url flag.

For example:

resolution --ethereum-url https://mainnet.infura.io/v3/${secret} -d udtestdev-usdt.crypto -a

Use the -h or --help flag to see all the available CLI options.

Default Ethereum Providers

Resolution provides zero-configuration experience by using built-in production-ready Infura endpoint by default. Default Ethereum provider is free to use without restrictions and rate-limits for CNS (.crypto domains) resolution.

To resolve ENS domains on production it's recommended to change Ethereum provider.
Default provider can be changed by changing constructor options new Resolution(options) or by using one of the factory methods:

• Resolution.infura()
• Resolution.fromWeb3Version1Provider()
• Resolution.fromEthersProvider()
• etc.

To see all constructor options and factory methods check the Unstoppable API reference.

Autoconfiguration of Blockchain Network

In some scenarios, the system might not be flexible enough to easily distinguish between various Ethereum testnets on compile time. For such cases, the resolution library provides a special async constructor which should be waited for await Resolution.autonetwork(options). This method makes a JSON RPC "net_version" call to the provider to get the network id.

This method configures CNS and UNS. ZNS is supported only on Zilliqa mainnet. You can provide a configured provider or a blockchain url as in the following example:

Resolution.autoNetwork({
    uns: {
        locations: {
            Layer1: {
                url: 'http://alchemy.com/ethereum/api-key'
            },
            Layer2: {
                url: 'http://alchemy.com/polygon/api-key'
            }
        }
    }
})

Error Handling

When resolution encounters an error it returns the error code instead of stopping the process. Keep an eye out for return values like RECORD_NOT_FOUND.

Development

Use these commands to set up a local development environment (macOS Terminal or Linux shell).

1. Install nvm

   curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.36.0/install.sh | bash

2. Install concrete version of node.js

   nvm install 12.12.0

3. Install yarn

   npm install -g yarn

4. Clone the repository

   git clone https://github.com/unstoppabledomains/resolution.git
   cd resolution

5. Install dependencies

   yarn install

Internal Config

To update:

• Network config: $ yarn network-config:pull
• Supported keys: $ yarn supported-keys:pull
• Both configs: $ yarn config:pull

Asking For Help

Please don't be shy; we're here to help. Join our Discord channel for real-time support from UD and the community if you need assistance integrating your app.