55283d3c91
`resolver` isn't suitable name for the package with NeoFS name system functionality. Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
117 lines
3.4 KiB
Go
117 lines
3.4 KiB
Go
package ns
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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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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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"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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cid "github.com/nspcc-dev/neofs-sdk-go/container/id"
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)
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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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// client is a core implementation of internal NNS.neoClient which is used by NNS.Dial.
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type client neoclient.WSClient
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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.WSClient)(x).InvokeFunction(contract, method, prm, nil)
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}
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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.NewWS(context.Background(), address, neoclient.Options{})
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if err != nil {
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return fmt.Errorf("create neo client: %w", err)
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}
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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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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 + ".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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})
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if err != nil {
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return nil, fmt.Errorf("invoke NNS contract: %w", err)
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}
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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, fmt.Errorf("convert stack item to %s", stackitem.ArrayT)
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}
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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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// 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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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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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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}
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}
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return nil, errNotFound
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}
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