Ethereum Name Service¶

The Ethereum Name Service is analogous to the Domain Name Service. It enables users and developers to use human-friendly names in place of error-prone hexadecimal addresses, content hashes, and more.

The ens module is included with web3.py. It provides an interface to look up an address from a name, set up your own address, and more.

Setup¶

Create an ENS object (named ns below) in one of three ways:

Automatic detection
Specify an instance or list of Providers
From an existing web3.Web3 object

# automatic detection
from ens.auto import ns


# or, with a provider
from web3 import IPCProvider
from ens import ENS

provider = IPCProvider(...)
ns = ENS(provider)


# or, with a w3 instance
from ens import ENS

w3 = Web3(...)
ns = ENS.fromWeb3(w3)

Usage¶

Name info¶

Look up the address for an ENS name¶

from ens.auto import ns

# look up the hex representation of the address for a name

eth_address = ns.address('jasoncarver.eth')

assert eth_address == '0x5B2063246F2191f18F2675ceDB8b28102e957458'

# ens.py will assume you want a .eth name if you don't specify a full name

assert ns.address('jasoncarver') == eth_address

Get name from address¶

domain = ns.name('0x5B2063246F2191f18F2675ceDB8b28102e957458')

# name() also accepts the bytes version of the address

assert ns.name(b'[ c$o!\x91\xf1\x8f&u\xce\xdb\x8b(\x10.\x95tX') == domain

# confirm that the name resolves back to the address that you looked up:

assert ns.address(domain) == '0x5B2063246F2191f18F2675ceDB8b28102e957458'

Get owner of name¶

eth_address = ns.owner('exchange.eth')

Set up your name¶

Point your name to your address¶

Do you want to set up your name so that address() will show the address it points to?

ns.setup_address('jasoncarver.eth', '0x5B2063246F2191f18F2675ceDB8b28102e957458')

You must already be the owner of the domain (or its parent).

In the common case where you want to point the name to the owning address, you can skip the address

ns.setup_address('jasoncarver.eth')

You can claim arbitrarily deep subdomains. Gas costs scale up with the number of subdomains!

ns.setup_address('supreme.executive.power.derives.from.a.mandate.from.the.masses.jasoncarver.eth')

Wait for the transaction to be mined, then:

assert ns.address('supreme.executive.power.derives.from.a.mandate.from.the.masses.jasoncarver.eth') == \
    '0x5B2063246F2191f18F2675ceDB8b28102e957458'

Allow people to find your name using your address¶

Do you want to set up your address so that name() will show the name that points to it?

This is like Caller ID. It enables you and others to take an account and determine what name points to it. Sometimes this is referred to as “reverse” resolution.

ns.setup_name('jasoncarver.eth', '0x5B2063246F2191f18F2675ceDB8b28102e957458')

Note

Do not rely on reverse resolution for security.

Anyone can claim any “caller ID”. Only forward resolution implies that the owner of the name gave their stamp of approval.

If you don’t supply the address, setup_name() will assume you want the address returned by address().

ns.setup_name('jasoncarver.eth')

If the name doesn’t already point to an address, setup_name() will call setup_address() for you.

Wait for the transaction to be mined, then:

assert ns.name('0x5B2063246F2191f18F2675ceDB8b28102e957458') == 'jasoncarver.eth'