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Resolution-Go

This page details basic configuration and usage of the resolution-go library.

Configuration

Resolution libraries require a connection to the Ethereum network to resolve .crypto and .eth domains. To initialize the library, you need to specify an Ethereum node service provider. Once the instance is created you can begin resolving domains. Below are examples of how to initialize the library with different providers.

Provider URL

Each of the resolution libraries supports an Ethereum provider url for configuration. You can obtain a provider url from a service like Alchemy where obtaining an API key is free and only requires creating an account.

To choose an alternative Ethereum provider see Nodes as a Service guide.

info

Unstoppable libraries use Infura as a provider by default without restrictions and rate limits for UNS resolution. Default configuration can be considered production-ready.

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import (
    "github.com/ethereum/go-ethereum/ethclient"
	"github.com/unstoppabledomains/resolution-go/v2"
)

var infuraApiKey = INFURA_PROJECT_ID
var ethereumUrl = "https://mainnet.infura.io/v3/" + infuraApiKey
var ethereumL2Url = "https://polygon-mumbai.infura.io/v3/" + infuraApiKey

var unsBuilder := resolution.NewUnsBuilder()
var backend, _ := ethclient.Dial(ethereumUrl)
var backendL2, _ := ethclient.Dial(ethereumL2Url)

unsBuilder.SetContractBackend(backend)
unsBuilder.SetL2ContractBackend(backendL2)

var unsResolution, _ = unsBuilder.Build()
var znsResolution, _ = resolution.NewZnsBuilder().Build()
warning

Make sure to allow mainnet.infura.io and polygon-mainnet.infura.io or simply https://*.infura.io (if using the default configuration) as a connect-src in your Content Security Policy to allow these requests through.

Error Handling

Unstoppable Domains follows the error handling best practices specific to each library's language. Each error data structure contains an error code, a human-readable message, and extra details that may help you debug the error.

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{
  code: string; // one of our custom error codes
  message?: string; // human-readable error summary
  providerMessage?: string; // internal error message from the provider (alchemy, infura, etc.)
  errorMessage?: string; // internal error message / nested error
  method?: ResolutionMethod; // resolution method (UNS L1, UNS L2, CNS, ZNS, UD API)
  methodName?: string; // resolution method that was used (e.g. Resolution.addr, Resolution.allRecords)
  domain?: string; // domain that caused the error
  currencyTicker?: string; // currency ticker that caused the error
  recordName?: string; // record that caused the error
  namingService?: string; // naming service (UNSL1, UNSL2, ZNS, ENS, CNS, etc.)
  location?: UnsLocation; // domain location (L1, L2)
  tokenUri?: string; // domain metadata link
}

The code snippet below shows how to handle the common error cases you may encounter during integration, including:

  • Resolving an unregistered domain
  • Resolving an undefined record of a domain
  • Resolving a misconfigured domain
  • Resolving a domain with an unsupported domain ending

We handle the errors thrown by the resolution library by switching on the error code and displaying custom messages to the user. You can then perform other actions to handle the error or show the error message value from the error data structure to the user.

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package main

import (
    "fmt"
    "github.com/unstoppabledomains/resolution-go"
)

func main() {
    uns, err := resolution.NewUnsBuilder().Build()

    if err != nil {
        switch err.(type) {
        // UnsConfigurationError Error when UNS resolution service is configured incorrectly
        case *resolution.UnsConfigurationError:
            fmt.Println("Uns configuration error:", err.Error())
        default:
            fmt.Println("Unknown error")
        }
    }

    address, err := uns.Addr("domain-with-error.crypto", "ETH")

    if err != nil {
        switch err.(type) {
        // DomainNotRegisteredError Error when domain is missing an owner
        case *resolution.DomainNotRegisteredError:
            fmt.Println("DomainNotRegisteredError:", err.Error())
        // DomainNotConfiguredError Error when domain does not have a resolver set
        case *resolution.DomainNotConfiguredError:
            fmt.Println("DomainNotConfiguredError:", err.Error())
        // DomainNotSupportedError Error when domain is not supported by the naming service
        case *resolution.DomainNotSupportedError:
            fmt.Println("DomainNotSupportedError:", err.Error())
        // MethodIsNotSupportedError Error when naming services does not support called method
        case *resolution.MethodIsNotSupportedError:
            fmt.Println("MethodIsNotSupportedError:", err.Error())
        // InvalidDomainNameReturnedError Error when ERC721 metadata provides returns incorrect domain name
        case *resolution.InvalidDomainNameReturnedError:
            fmt.Println("InvalidDomainNameReturnedError:", err.Error())
        default:
            fmt.Println("Unknown error")
        }
    }
}

Error Codes

Error Code Description
DomainNotConfiguredError Thrown when the domain resolver contract address is not found. For example, the domain doesn't have a specified resolver.
DomainNotRegisteredError Thrown when you resolve a domain not owned by any address.
DomainNotSupportedError Thrown when you resolve a domain with an ending not supported by the current resolution instance.
InvalidDomainNameReturnedError Thrown when you resolve an invalid domain address.
MethodIsNotSupportedError Thrown when you use a method of the current resolution instance not supported by the naming service you're resolving from. For example, using the TokenURI(), TokenURIMetadata(), and Unhash() methods for the Zilliqa Name Service (ZNS).
UnsConfigurationError Thrown when the UNS resolution service is misconfigured.

Use Case: Retrieve a Domain Record

Retrieve any record of a domain. Applications sometimes set custom records for a domain to use within their application. The code snippet below show how to do this in Golang.

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uns, _ := resolution.NewUnsBuilder().Build()
ethAddress, _ := uns.Addr("brad.crypto", "ETH")
fmt.Println("ETH address for brad.crypto is", ethAddress)

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