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package proxy
import (
"github.com/pkg/errors"
cmn "github.com/tendermint/tendermint/libs/common"
"github.com/tendermint/tendermint/lite"
"github.com/tendermint/tendermint/lite/client"
certerr "github.com/tendermint/tendermint/lite/errors"
rpcclient "github.com/tendermint/tendermint/rpc/client"
ctypes "github.com/tendermint/tendermint/rpc/core/types"
)
// KeyProof represents a proof of existence or absence of a single key.
// Copied from iavl repo. TODO
type KeyProof interface {
// Verify verfies the proof is valid. To verify absence,
// the value should be nil.
Verify(key, value, root []byte) error
// Root returns the root hash of the proof.
Root() []byte
// Serialize itself
Bytes() []byte
}
// GetWithProof will query the key on the given node, and verify it has
// a valid proof, as defined by the certifier.
//
// If there is any error in checking, returns an error.
// If val is non-empty, proof should be KeyExistsProof
// If val is empty, proof should be KeyMissingProof
func GetWithProof(key []byte, reqHeight int64, node rpcclient.Client,
cert lite.Certifier) (
val cmn.HexBytes, height int64, proof KeyProof, err error) {
if reqHeight < 0 {
err = errors.Errorf("Height cannot be negative")
return
}
_resp, proof, err := GetWithProofOptions("/key", key,
rpcclient.ABCIQueryOptions{Height: int64(reqHeight)},
node, cert)
if _resp != nil {
resp := _resp.Response
val, height = resp.Value, resp.Height
}
return val, height, proof, err
}
// GetWithProofOptions is useful if you want full access to the ABCIQueryOptions
func GetWithProofOptions(path string, key []byte, opts rpcclient.ABCIQueryOptions,
node rpcclient.Client, cert lite.Certifier) (
*ctypes.ResultABCIQuery, KeyProof, error) {
_resp, err := node.ABCIQueryWithOptions(path, key, opts)
if err != nil {
return nil, nil, err
}
resp := _resp.Response
// make sure the proof is the proper height
if resp.IsErr() {
err = errors.Errorf("Query error for key %d: %d", key, resp.Code)
return nil, nil, err
}
if len(resp.Key) == 0 || len(resp.Proof) == 0 {
return nil, nil, ErrNoData()
}
if resp.Height == 0 {
return nil, nil, errors.New("Height returned is zero")
}
// AppHash for height H is in header H+1
commit, err := GetCertifiedCommit(resp.Height+1, node, cert)
if err != nil {
return nil, nil, err
}
_ = commit
return &ctypes.ResultABCIQuery{Response: resp}, nil, nil
/* // TODO refactor so iavl stuff is not in tendermint core
// https://github.com/tendermint/tendermint/issues/1183
if len(resp.Value) > 0 {
// The key was found, construct a proof of existence.
proof, err := iavl.ReadKeyProof(resp.Proof)
if err != nil {
return nil, nil, errors.Wrap(err, "Error reading proof")
}
eproof, ok := proof.(*iavl.KeyExistsProof)
if !ok {
return nil, nil, errors.New("Expected KeyExistsProof for non-empty value")
}
// Validate the proof against the certified header to ensure data integrity.
err = eproof.Verify(resp.Key, resp.Value, commit.Header.AppHash)
if err != nil {
return nil, nil, errors.Wrap(err, "Couldn't verify proof")
}
return &ctypes.ResultABCIQuery{Response: resp}, eproof, nil
}
// The key wasn't found, construct a proof of non-existence.
proof, err := iavl.ReadKeyProof(resp.Proof)
if err != nil {
return nil, nil, errors.Wrap(err, "Error reading proof")
}
aproof, ok := proof.(*iavl.KeyAbsentProof)
if !ok {
return nil, nil, errors.New("Expected KeyAbsentProof for empty Value")
}
// Validate the proof against the certified header to ensure data integrity.
err = aproof.Verify(resp.Key, nil, commit.Header.AppHash)
if err != nil {
return nil, nil, errors.Wrap(err, "Couldn't verify proof")
}
return &ctypes.ResultABCIQuery{Response: resp}, aproof, ErrNoData()
*/
}
// GetCertifiedCommit gets the signed header for a given height
// and certifies it. Returns error if unable to get a proven header.
func GetCertifiedCommit(h int64, node rpcclient.Client, cert lite.Certifier) (lite.Commit, error) {
// FIXME: cannot use cert.GetByHeight for now, as it also requires
// Validators and will fail on querying tendermint for non-current height.
// When this is supported, we should use it instead...
rpcclient.WaitForHeight(node, h, nil)
cresp, err := node.Commit(&h)
if err != nil {
return lite.Commit{}, err
}
commit := client.CommitFromResult(cresp)
// validate downloaded checkpoint with our request and trust store.
if commit.Height() != h {
return lite.Commit{}, certerr.ErrHeightMismatch(h, commit.Height())
}
if err = cert.Certify(commit); err != nil {
return lite.Commit{}, err
}
return commit, nil
}