frostfs-sdk-go/ns/nns.go

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package ns
import (
"context"
"fmt"
"net/url"
"github.com/nspcc-dev/neo-go/pkg/core/state"
"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
"github.com/nspcc-dev/neo-go/pkg/rpcclient"
"github.com/nspcc-dev/neo-go/pkg/rpcclient/invoker"
"github.com/nspcc-dev/neo-go/pkg/rpcclient/unwrap"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/nspcc-dev/neofs-contract/nns"
cid "github.com/nspcc-dev/neofs-sdk-go/container/id"
)
// NNS looks up NeoFS names using Neo Name Service.
//
// Instances are created with a variable declaration. Before work, the connection
// to the NNS server MUST be established using Dial method.
type NNS struct {
nnsContract util.Uint160
invoker interface {
Call(contract util.Uint160, operation string, params ...interface{}) (*result.Invoke, error)
}
}
// Dial connects to the address of the NNS server. If fails, the instance
// MUST NOT be used.
//
// If URL address scheme is 'ws' or 'wss', then WebSocket protocol is used,
// otherwise HTTP.
func (n *NNS) Dial(address string) error {
// multiSchemeClient unites invoker.RPCInvoke and common interface of
// rpcclient.Client and rpcclient.WSClient. Interface is anonymous
// according to assumption that common interface of these client types
// is not required by design and may diverge with changes.
var multiSchemeClient interface {
invoker.RPCInvoke
// Init turns client to "ready-to-work" state.
Init() error
// GetContractStateByID returns state of the NNS contract on 1 input.
GetContractStateByID(int32) (*state.Contract, error)
}
var err error
uri, err := url.Parse(address)
if err == nil && (uri.Scheme == "ws" || uri.Scheme == "wss") {
multiSchemeClient, err = rpcclient.NewWS(context.Background(), address, rpcclient.Options{})
if err != nil {
return fmt.Errorf("create Neo WebSocket client: %w", err)
}
} else {
multiSchemeClient, err = rpcclient.New(context.Background(), address, rpcclient.Options{})
if err != nil {
return fmt.Errorf("create Neo HTTP client: %w", err)
}
}
if err = multiSchemeClient.Init(); err != nil {
return fmt.Errorf("initialize Neo client: %w", err)
}
nnsContract, err := multiSchemeClient.GetContractStateByID(1)
if err != nil {
return fmt.Errorf("get NNS contract state: %w", err)
}
n.invoker = invoker.New(multiSchemeClient, nil)
n.nnsContract = nnsContract.Hash
return nil
}
// ResolveContainerName looks up for NNS TXT records for the given container name
// by calling `resolve` method of NNS contract. Returns the first record which represents
// valid container ID in a string format. Otherwise, returns an error.
//
// ResolveContainerName MUST NOT be called before successful Dial.
//
// See also https://docs.neo.org/docs/en-us/reference/nns.html.
func (n *NNS) ResolveContainerName(name string) (cid.ID, error) {
arr, err := unwrap.Array(n.invoker.Call(n.nnsContract, "resolve",
name+".container", int64(nns.TXT),
))
if err != nil {
return cid.ID{}, fmt.Errorf("contract invocation: %w", err)
}
var id cid.ID
for i := range arr {
bs, err := arr[i].TryBytes()
if err != nil {
return cid.ID{}, fmt.Errorf("convert array item to byte slice: %w", err)
}
err = id.DecodeString(string(bs))
if err == nil {
return id, nil
}
}
return cid.ID{}, errNotFound
}