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Tezos Domains

A Tezos domain is a feature that allows users of the Tezos blockchain to use a human-readable and easy to remember address (for example, alice.tez) instead of a long string of letters and numbers (for example, tz1VSUr8wwNhLAzempoch5d6hLRiTh8Cjcjb). The data about which address owns which domain is stored as a token inside a smart contract, so it's possible to find this piece of information when inspecting the storage of the contract.

Let's have a look at the Tezos domain contract on testnet to see how we can find a domain associated to an address and vice-versa.

Note: the domains have a different extension on the various networks. All the domains on mainnet have the .tez extension while the domains on florencenet have a .flo extension. However, the contracts work exactly in the same way.

Looking up an address

If you have an address and you want to find the domain tied to it, the storage of the Tezos domain contract holds a bigmap called reverse_records whose keys are addresses and whose values include the corresponding Tezos domain. Here is a little function to fetch it:

import { TezosToolkit } from "@taquito/taquito";
import { bytes2Char } from "@taquito/utils";
const domainContractAddress = "KT1PfBfkfUuvQRN8zuCAyp5MHjNrQqgevS9p";
// the function returns the domain name if found or the provided address
const fetchTezosDomainFromAddress = async (address: string): Promise<string> => {
const Tezos = new TezosToolkit("https://testnet-tezos.giganode.io");
const contract = await Tezos.wallet.at(domainContractAddress);
const storage: any = await contract.storage();
const domain = await storage.store.reverse_records.get(address);
if (domain) {
return bytes2Char(domain.name);
} else {
return address;
}
};

2 things to remember when you are looking for a Tezos domain in the storage of the contract:

  • the reverse_records bigmap is nested inside the store property
  • the domain name is stored as bytes, so you can use the bytes2Char function from @taquito/utils to decode it as a string.

If we call the fetchTezosDomainFromAddress function with tz1VSUr8wwNhLAzempoch5d6hLRiTh8Cjcjb, it will return alice-tezos.flo.

Looking up a Tezos domain

It is also possible to look up a domain name to find the address it references. In this case, you will use the records bigmap that you can also find under the store property of the storage:

import { TezosToolkit } from "@taquito/taquito";
import { char2Bytes } from "@taquito/utils";
const contractAddress = "KT1PfBfkfUuvQRN8zuCAyp5MHjNrQqgevS9p";
// the function returns the address if found or the provided domain name
const fetchAddressFromTezosDomain = async (domainName: string): Promise<string> => {
const Tezos = new TezosToolkit("https://testnet-tezos.giganode.io");
const contract = await Tezos.wallet.at(contractAddress);
const storage: any = await contract.storage();
const domain = await storage.store.records.get(char2Bytes(domainName));
if (domain) {
return domain.owner;
} else {
return domainName;
}
};

This function works in the same manner as the previous one, but the owner's address is a simple address and doesn't need to be decoded.

Looking up the expiry date of a domain

The Tezos domains have an expiry date after which they must be renewed or they will be available again. To find the expiry date, you can check the expiry_map bigmap under the store property of the storage where the keys are the domain names encoded into bytes:

import { TezosToolkit } from "@taquito/taquito";
import { char2Bytes } from "@taquito/utils";
const contractAddress = "KT1PfBfkfUuvQRN8zuCAyp5MHjNrQqgevS9p";
// this function return the expiry date of a domain name
const fetchExpiryDate = async (domainName: string): Promise<string> => {
const Tezos = new TezosToolkit("https://testnet-tezos.giganode.io");
const contract = await Tezos.wallet.at(contractAddress);
const storage: any = await contract.storage();
const expiryDate = await storage.store.expiry_map.get(char2Bytes(domainName));
if (expiryDate) {
return expiryDate;
} else {
return "not a valid domain name";
}
}

If you provide alice-tezos.flo as a parameter, the function will return 2022-06-09T09:06:20Z, meaning that the domain name expires in June 9th, 2022.