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- package proxy
-
- import (
- "github.com/pkg/errors"
-
- "github.com/tendermint/go-wire/data"
- "github.com/tendermint/iavl"
-
- "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"
- )
-
- // 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 data.Bytes, height int64, proof iavl.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, iavl.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 %d: %d", 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
- }
-
- if len(resp.Value) > 0 {
- // The key was found, construct a proof of existence.
- eproof, err := iavl.ReadKeyExistsProof(resp.Proof)
- if err != nil {
- return nil, nil, errors.Wrap(err, "Error reading proof")
- }
-
- // 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{resp}, eproof, nil
- }
-
- // The key wasn't found, construct a proof of non-existence.
- var aproof *iavl.KeyAbsentProof
- aproof, err = iavl.ReadKeyAbsentProof(resp.Proof)
- if err != nil {
- return nil, nil, errors.Wrap(err, "Error reading proof")
- }
- // 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{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) (empty lite.Commit, err 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
- }
- commit := client.CommitFromResult(cresp)
-
- // validate downloaded checkpoint with our request and trust store.
- if commit.Height() != h {
- return empty, certerr.ErrHeightMismatch(h, commit.Height())
- }
- err = cert.Certify(commit)
- return commit, nil
- }
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