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