forked from TrueCloudLab/frostfs-sdk-go
[#179] resolver: Refactor and document the package
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
This commit is contained in:
Leonard Lyubich
LeL
parent
c961aea144
commit
146fc4f07a
5 changed files with 276 additions and 102 deletions
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@ -1,41 +1,35 @@
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package resolver
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import (
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"fmt"
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"net"
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cid "github.com/nspcc-dev/neofs-sdk-go/container/id"
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)
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const (
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testnetDomain = ".containers.testnet.fs.neo.org"
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mainnetDomain = ".containers.fs.neo.org"
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)
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// DNS looks up NeoFS names using system DNS.
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//
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// See also net package.
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type DNS struct{}
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// ResolveContainerTestnet request txt record name + '.containers.testnet.fs.neo.org' to default dns server.
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func ResolveContainerTestnet(name string) (*cid.ID, error) {
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return ResolveContainerDomainName(name + testnetDomain)
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}
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// ResolveContainerMainnet request txt record name + '.containers.fs.neo.org' to default dns server.
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func ResolveContainerMainnet(name string) (*cid.ID, error) {
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return ResolveContainerDomainName(name + mainnetDomain)
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}
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// ResolveContainerDomainName trys to resolve container domain name to container ID using system dns server.
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func ResolveContainerDomainName(domain string) (*cid.ID, error) {
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results, err := net.LookupTXT(domain)
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// ResolveContainerName looks up for DNS TXT records for the given domain name
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// and returns the first one which represents valid container ID in a string format.
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// Otherwise, returns an error.
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//
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// See also net.LookupTXT.
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func (x *DNS) ResolveContainerName(name string) (*cid.ID, error) {
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records, err := net.LookupTXT(name)
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if err != nil {
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return nil, err
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}
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cnrID := cid.New()
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for _, res := range results {
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if err = cnrID.Parse(res); err != nil {
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continue
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var id cid.ID
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for i := range records {
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err = id.Parse(records[i])
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if err == nil {
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return &id, nil
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}
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return cnrID, nil
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}
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return nil, fmt.Errorf("not found")
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return nil, errNotFound
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}
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22
resolver/doc.go
Normal file
22
resolver/doc.go
Normal file
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@ -0,0 +1,22 @@
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/*
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Package resolver provides functionality of NeoFS name system.
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DNS type is designed to resolve NeoFS-related names using Domain Name System:
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const containerName = "some-container"
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var dns DNS
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containerID, err := dns.ResolveContainerName(containerName)
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// ...
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NNS type is designed to resolve NeoFS-related names using Neo Name Service:
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var nns NNS
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err := nns.Dial(nnsServerAddress)
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// ...
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containerID, err := nns.ResolveContainerName(containerName)
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// ...
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*/
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package resolver
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154
resolver/nns.go
154
resolver/nns.go
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@ -1,10 +1,12 @@
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package resolver
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import (
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"context"
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"errors"
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"fmt"
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nns "github.com/nspcc-dev/neo-go/examples/nft-nd-nns"
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"github.com/nspcc-dev/neo-go/pkg/rpc/client"
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neoclient "github.com/nspcc-dev/neo-go/pkg/rpc/client"
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"github.com/nspcc-dev/neo-go/pkg/rpc/response/result"
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"github.com/nspcc-dev/neo-go/pkg/smartcontract"
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"github.com/nspcc-dev/neo-go/pkg/util"
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@ -13,109 +15,103 @@ import (
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cid "github.com/nspcc-dev/neofs-sdk-go/container/id"
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)
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type NNSResolver interface {
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// ResolveContainerName get record for domain name+'.container' from NNS contract.
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ResolveContainerName(name string) (*cid.ID, error)
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// NNS looks up NeoFS names using Neo Name Service.
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//
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// Instances are created with a variable declaration. Before work, the connection
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// to the NNS server MUST BE established using Dial method.
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type NNS struct {
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nnsContract util.Uint160
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// neoclient.Client interface wrapper, needed for testing
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neoClient interface {
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invoke(contract util.Uint160, method string, prm []smartcontract.Parameter) (*result.Invoke, error)
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}
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}
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type nnsResolver struct {
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rpc *client.Client
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nnsHash util.Uint160
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// client is a core implementation of internal NNS.neoClient which is used by NNS.Dial.
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type client neoclient.Client
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func (x *client) invoke(contract util.Uint160, method string, prm []smartcontract.Parameter) (*result.Invoke, error) {
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return (*neoclient.Client)(x).InvokeFunction(contract, method, prm, nil)
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}
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const (
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resolve = "resolve"
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containerDomain = ".container"
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)
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// NewNNSResolver creates resolver that can get records from NNS contract.
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func NewNNSResolver(rpc *client.Client) (NNSResolver, error) {
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nnsContract, err := rpc.GetContractStateByID(1)
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// Dial connects to the address of the NNS server. If fails, the instance
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// SHOULD NOT be used.
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func (n *NNS) Dial(address string) error {
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cli, err := neoclient.New(context.Background(), address, neoclient.Options{})
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if err != nil {
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return nil, err
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return fmt.Errorf("create neo client: %w", err)
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}
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return &nnsResolver{
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rpc: rpc,
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nnsHash: nnsContract.Hash,
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}, nil
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if err = cli.Init(); err != nil {
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return fmt.Errorf("initialize neo client: %w", err)
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}
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func (n *nnsResolver) ResolveContainerName(name string) (*cid.ID, error) {
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res, err := n.rpc.InvokeFunction(n.nnsHash, resolve, []smartcontract.Parameter{
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nnsContract, err := cli.GetContractStateByID(1)
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if err != nil {
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return fmt.Errorf("get NNS contract state: %w", err)
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}
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n.neoClient = (*client)(cli)
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n.nnsContract = nnsContract.Hash
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return nil
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}
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// ResolveContainerName looks up for NNS TXT records for the given container name
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// by calling `resolve` method of NNS contract. Returns the first record which represents
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// valid container ID in a string format. Otherwise, returns an error.
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//
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// ResolveContainerName MUST NOT be called before successful Dial.
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//
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// See also https://docs.neo.org/docs/en-us/reference/nns.html.
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func (n *NNS) ResolveContainerName(name string) (*cid.ID, error) {
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res, err := n.neoClient.invoke(n.nnsContract, "resolve", []smartcontract.Parameter{
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{
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Type: smartcontract.StringType,
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Value: name + containerDomain,
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Value: name + ".container",
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},
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{
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Type: smartcontract.IntegerType,
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Value: int64(nns.TXT),
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},
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}, nil)
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})
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if err != nil {
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return nil, err
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}
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if err = getInvocationError(res); err != nil {
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return nil, err
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return nil, fmt.Errorf("invoke NNS contract: %w", err)
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}
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arr, err := getArrString(res.Stack)
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if res.State != vm.HaltState.String() {
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return nil, fmt.Errorf("NNS contract fault exception: %s", res.FaultException)
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} else if len(res.Stack) == 0 {
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return nil, errors.New("empty stack in invocation result")
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}
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itemArr, err := res.Stack[len(res.Stack)-1].Convert(stackitem.ArrayT) // top stack element is last in the array
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if err != nil {
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return nil, err
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return nil, fmt.Errorf("convert stack item to %s", stackitem.ArrayT)
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}
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cnrID := cid.New()
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for _, rec := range arr {
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if err = cnrID.Parse(rec); err != nil {
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continue
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}
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return cnrID, nil
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}
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return nil, fmt.Errorf("not found")
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}
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func getArrString(st []stackitem.Item) ([]string, error) {
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array, err := getArray(st)
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if err != nil {
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return nil, err
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}
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res := make([]string, len(array))
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for i, item := range array {
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bs, err := item.TryBytes()
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if err != nil {
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return nil, err
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}
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res[i] = string(bs)
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}
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return res, nil
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}
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func getArray(st []stackitem.Item) ([]stackitem.Item, error) {
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index := len(st) - 1 // top stack element is last in the array
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arr, err := st[index].Convert(stackitem.ArrayT)
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if err != nil {
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return nil, err
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}
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if _, ok := arr.(stackitem.Null); ok {
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return nil, nil
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}
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iterator, ok := arr.Value().([]stackitem.Item)
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if _, ok := itemArr.(stackitem.Null); !ok {
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arr, ok := itemArr.Value().([]stackitem.Item)
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if !ok {
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return nil, fmt.Errorf("bad conversion")
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}
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return iterator, nil
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// unexpected for types from stackitem package
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return nil, errors.New("invalid cast to stack item slice")
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}
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func getInvocationError(result *result.Invoke) error {
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if result.State != vm.HaltState.String() {
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return fmt.Errorf("invocation failed: %s", result.FaultException)
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var id cid.ID
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for i := range arr {
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bs, err := arr[i].TryBytes()
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if err != nil {
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return nil, fmt.Errorf("convert array item to byte slice: %w", err)
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}
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if len(result.Stack) == 0 {
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return fmt.Errorf("result stack is empty")
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err = id.Parse(string(bs))
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if err == nil {
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return &id, nil
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}
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return nil
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}
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}
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return nil, errNotFound
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}
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157
resolver/nns_test.go
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157
resolver/nns_test.go
Normal file
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@ -0,0 +1,157 @@
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package resolver
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import (
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"errors"
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"fmt"
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"math/big"
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"math/rand"
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"strings"
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"testing"
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nns "github.com/nspcc-dev/neo-go/examples/nft-nd-nns"
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"github.com/nspcc-dev/neo-go/pkg/rpc/response/result"
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"github.com/nspcc-dev/neo-go/pkg/smartcontract"
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"github.com/nspcc-dev/neo-go/pkg/util"
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"github.com/nspcc-dev/neo-go/pkg/vm"
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"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
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cidtest "github.com/nspcc-dev/neofs-sdk-go/container/id/test"
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"github.com/stretchr/testify/require"
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)
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// testNeoClient represents test Neo client which checks invocation arguments
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// and returns predefined result.
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type testNeoClient struct {
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t *testing.T
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expectedContract util.Uint160
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res result.Invoke
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err error
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}
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func (x *testNeoClient) invoke(contract util.Uint160, method string, prm []smartcontract.Parameter) (*result.Invoke, error) {
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require.Equal(x.t, x.expectedContract, contract)
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require.Equal(x.t, "resolve", method)
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require.Len(x.t, prm, 2)
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require.Equal(x.t, smartcontract.StringType, prm[0].Type)
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require.Equal(x.t, smartcontract.IntegerType, prm[1].Type)
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require.EqualValues(x.t, nns.TXT, prm[1].Value)
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val, ok := prm[0].Value.(string)
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require.True(x.t, ok)
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require.True(x.t, strings.HasSuffix(val, ".container"))
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require.NotEmpty(x.t, strings.TrimSuffix(val, ".container"))
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return &x.res, x.err
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}
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// implements test stackitem.Item which is obviously incorrect:
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// it returns itself on Convert(stackitem.ArrayT), but returns integer from Value.
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type brokenArrayStackItem struct {
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stackitem.Item
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}
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func (x brokenArrayStackItem) Value() interface{} {
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return 1
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}
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func (x brokenArrayStackItem) Convert(t stackitem.Type) (stackitem.Item, error) {
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if t != stackitem.ArrayT {
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panic(fmt.Sprintf("unexpected stack item type %s", t))
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}
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return x, nil
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}
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func TestNNS_ResolveContainerName(t *testing.T) {
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const testContainerName = "some_container"
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var nnsContract util.Uint160
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rand.Read(nnsContract[:])
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testC := &testNeoClient{
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t: t,
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expectedContract: nnsContract,
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}
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n := NNS{
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nnsContract: nnsContract,
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neoClient: testC,
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}
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t.Run("invocation failure", func(t *testing.T) {
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testC.err = errors.New("invoke err")
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_, err := n.ResolveContainerName(testContainerName)
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require.Error(t, err)
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})
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testC.err = nil
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t.Run("fault exception", func(t *testing.T) {
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_, err := n.ResolveContainerName(testContainerName)
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require.Error(t, err)
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})
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testC.res.State = vm.HaltState.String()
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t.Run("empty stack", func(t *testing.T) {
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_, err := n.ResolveContainerName(testContainerName)
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require.Error(t, err)
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})
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testC.res.Stack = make([]stackitem.Item, 1)
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t.Run("non-array last stack item", func(t *testing.T) {
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testC.res.Stack[0] = stackitem.NewBigInteger(big.NewInt(11))
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_, err := n.ResolveContainerName(testContainerName)
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require.Error(t, err)
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})
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t.Run("null array", func(t *testing.T) {
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testC.res.Stack[0] = stackitem.Null{}
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_, err := n.ResolveContainerName(testContainerName)
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require.Error(t, err)
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})
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t.Run("array stack item with non-slice value", func(t *testing.T) {
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testC.res.Stack[0] = brokenArrayStackItem{}
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_, err := n.ResolveContainerName(testContainerName)
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require.Error(t, err)
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})
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arr := make([]stackitem.Item, 2)
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testC.res.Stack[0] = stackitem.NewArray(arr)
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t.Run("non-bytes array element", func(t *testing.T) {
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arr[0] = stackitem.NewArray(nil)
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_, err := n.ResolveContainerName(testContainerName)
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require.Error(t, err)
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})
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arr[0] = stackitem.NewByteArray([]byte("some byte array 1"))
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t.Run("non-container array elements", func(t *testing.T) {
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arr[1] = stackitem.NewByteArray([]byte("some byte array 2"))
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_, err := n.ResolveContainerName(testContainerName)
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require.Error(t, err)
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})
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t.Run("with container array element", func(t *testing.T) {
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id := cidtest.ID()
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arr[1] = stackitem.NewByteArray([]byte(id.String()))
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res, err := n.ResolveContainerName(testContainerName)
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require.NoError(t, err)
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require.Equal(t, id, res)
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})
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}
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5
resolver/util.go
Normal file
5
resolver/util.go
Normal file
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@ -0,0 +1,5 @@
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package resolver
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import "errors"
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var errNotFound = errors.New("record not found")
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