status-go/vendor/github.com/wealdtech/go-ens/v3/reverseresolver.go

122 lines
3.5 KiB
Go

// Copyright 2017-2019 Weald Technology Trading
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package ens
import (
"errors"
"fmt"
"github.com/ethereum/go-ethereum/accounts/abi/bind"
"github.com/ethereum/go-ethereum/common"
"github.com/wealdtech/go-ens/v3/contracts/reverseresolver"
)
// ReverseResolver is the structure for the reverse resolver contract
type ReverseResolver struct {
Contract *reverseresolver.Contract
ContractAddr common.Address
}
// NewReverseResolverFor creates a reverse resolver contract for the given address.
func NewReverseResolverFor(backend bind.ContractBackend, address common.Address) (*ReverseResolver, error) {
registry, err := NewRegistry(backend)
if err != nil {
return nil, err
}
// Now fetch the resolver.
domain := fmt.Sprintf("%x.addr.reverse", address.Bytes())
contractAddress, err := registry.ResolverAddress(domain)
if err != nil {
return nil, err
}
return NewReverseResolverAt(backend, contractAddress)
}
// NewReverseResolver obtains the reverse resolver
func NewReverseResolver(backend bind.ContractBackend) (*ReverseResolver, error) {
reverseRegistrar, err := NewReverseRegistrar(backend)
if err != nil {
return nil, err
}
// Now fetch the default resolver
address, err := reverseRegistrar.DefaultResolverAddress()
if err != nil {
return nil, err
}
return NewReverseResolverAt(backend, address)
}
// NewReverseResolverAt obtains the reverse resolver at a given address
func NewReverseResolverAt(backend bind.ContractBackend, address common.Address) (*ReverseResolver, error) {
// Instantiate the reverse registrar contract
contract, err := reverseresolver.NewContract(address, backend)
if err != nil {
return nil, err
}
// Ensure the contract is a resolver
nameHash, err := NameHash("0.addr.reverse")
if err != nil {
return nil, err
}
_, err = contract.Name(nil, nameHash)
if err != nil && err.Error() == "no contract code at given address" {
return nil, fmt.Errorf("not a resolver")
}
return &ReverseResolver{
Contract: contract,
ContractAddr: address,
}, nil
}
// Name obtains the name for an address
func (r *ReverseResolver) Name(address common.Address) (string, error) {
nameHash, err := NameHash(fmt.Sprintf("%s.addr.reverse", address.Hex()[2:]))
if err != nil {
return "", err
}
return r.Contract.Name(nil, nameHash)
}
// Format provides a string version of an address, reverse resolving it if possible
func Format(backend bind.ContractBackend, address common.Address) string {
result, err := ReverseResolve(backend, address)
if err != nil {
result = address.Hex()
}
return result
}
// ReverseResolve resolves an address in to an ENS name
// This will return an error if the name is not found or otherwise 0
func ReverseResolve(backend bind.ContractBackend, address common.Address) (string, error) {
resolver, err := NewReverseResolverFor(backend, address)
if err != nil {
return "", err
}
// Resolve the name
name, err := resolver.Name(address)
if name == "" {
err = errors.New("no resolution")
}
return name, err
}