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couchdoc_conv.go
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/
couchdoc_conv.go
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/*
Copyright IBM Corp. All Rights Reserved.
SPDX-License-Identifier: Apache-2.0
*/
package statecouchdb
import (
"bytes"
"encoding/json"
"strings"
"unicode/utf8"
"github.com/hyperledger/fabric/core/ledger/kvledger/txmgmt/statedb"
"github.com/hyperledger/fabric/core/ledger/kvledger/txmgmt/version"
"github.com/hyperledger/fabric/core/ledger/util/couchdb"
"github.com/pkg/errors"
)
const (
binaryWrapper = "valueBytes"
idField = "_id"
revField = "_rev"
versionField = "~version"
deletedField = "_deleted"
)
type keyValue struct {
key string
*statedb.VersionedValue
}
type jsonValue map[string]interface{}
func tryCastingToJSON(b []byte) (isJSON bool, val jsonValue) {
var jsonVal map[string]interface{}
err := json.Unmarshal(b, &jsonVal)
return err == nil, jsonValue(jsonVal)
}
func castToJSON(b []byte) (jsonValue, error) {
var jsonVal map[string]interface{}
err := json.Unmarshal(b, &jsonVal)
err = errors.Wrap(err, "error unmarshalling json data")
return jsonVal, err
}
func (v jsonValue) checkReservedFieldsNotPresent() error {
for fieldName := range v {
if fieldName == versionField || strings.HasPrefix(fieldName, "_") {
return errors.Errorf("field [%s] is not valid for the CouchDB state database", fieldName)
}
}
return nil
}
func (v jsonValue) removeRevField() {
delete(v, revField)
}
func (v jsonValue) toBytes() ([]byte, error) {
jsonBytes, err := json.Marshal(v)
err = errors.Wrap(err, "error marshalling json data")
return jsonBytes, err
}
func couchDocToKeyValue(doc *couchdb.CouchDoc) (*keyValue, error) {
// initialize the return value
var returnValue []byte
var err error
// create a generic map unmarshal the json
jsonResult := make(map[string]interface{})
decoder := json.NewDecoder(bytes.NewBuffer(doc.JSONValue))
decoder.UseNumber()
if err = decoder.Decode(&jsonResult); err != nil {
return nil, err
}
// verify the version field exists
if _, fieldFound := jsonResult[versionField]; !fieldFound {
return nil, errors.Errorf("version field %s was not found", versionField)
}
key := jsonResult[idField].(string)
// create the return version from the version field in the JSON
returnVersion, returnMetadata, err := decodeVersionAndMetadata(jsonResult[versionField].(string))
if err != nil {
return nil, err
}
// remove the _id, _rev and version fields
delete(jsonResult, idField)
delete(jsonResult, revField)
delete(jsonResult, versionField)
// handle binary or json data
if doc.Attachments != nil { // binary attachment
// get binary data from attachment
for _, attachment := range doc.Attachments {
if attachment.Name == binaryWrapper {
returnValue = attachment.AttachmentBytes
}
}
} else {
// marshal the returned JSON data.
if returnValue, err = json.Marshal(jsonResult); err != nil {
return nil, err
}
}
return &keyValue{key, &statedb.VersionedValue{
Value: returnValue,
Metadata: returnMetadata,
Version: returnVersion},
}, nil
}
func keyValToCouchDoc(kv *keyValue, revision string) (*couchdb.CouchDoc, error) {
type kvType int32
const (
kvTypeDelete = iota
kvTypeJSON
kvTypeAttachment
)
key, value, metadata, version := kv.key, kv.Value, kv.Metadata, kv.Version
jsonMap := make(jsonValue)
var kvtype kvType
switch {
case value == nil:
kvtype = kvTypeDelete
// check for the case where the jsonMap is nil, this will indicate
// a special case for the Unmarshal that results in a valid JSON returning nil
case json.Unmarshal(value, &jsonMap) == nil && jsonMap != nil:
kvtype = kvTypeJSON
if err := jsonMap.checkReservedFieldsNotPresent(); err != nil {
return nil, err
}
default:
// create an empty map, if the map is nil
if jsonMap == nil {
jsonMap = make(jsonValue)
}
kvtype = kvTypeAttachment
}
verAndMetadata, err := encodeVersionAndMetadata(version, metadata)
if err != nil {
return nil, err
}
// add the (version + metadata), id, revision, and delete marker (if needed)
jsonMap[versionField] = verAndMetadata
jsonMap[idField] = key
if revision != "" {
jsonMap[revField] = revision
}
if kvtype == kvTypeDelete {
jsonMap[deletedField] = true
}
jsonBytes, err := jsonMap.toBytes()
if err != nil {
return nil, err
}
couchDoc := &couchdb.CouchDoc{JSONValue: jsonBytes}
if kvtype == kvTypeAttachment {
attachment := &couchdb.AttachmentInfo{}
attachment.AttachmentBytes = value
attachment.ContentType = "application/octet-stream"
attachment.Name = binaryWrapper
attachments := append([]*couchdb.AttachmentInfo{}, attachment)
couchDoc.Attachments = attachments
}
return couchDoc, nil
}
// couchSavepointData data for couchdb
type couchSavepointData struct {
BlockNum uint64 `json:"BlockNum"`
TxNum uint64 `json:"TxNum"`
}
func encodeSavepoint(height *version.Height) (*couchdb.CouchDoc, error) {
var err error
var savepointDoc couchSavepointData
// construct savepoint document
savepointDoc.BlockNum = height.BlockNum
savepointDoc.TxNum = height.TxNum
savepointDocJSON, err := json.Marshal(savepointDoc)
if err != nil {
err = errors.Wrap(err, "failed to marshal savepoint data")
logger.Errorf("%+v", err)
return nil, err
}
return &couchdb.CouchDoc{JSONValue: savepointDocJSON, Attachments: nil}, nil
}
func decodeSavepoint(couchDoc *couchdb.CouchDoc) (*version.Height, error) {
savepointDoc := &couchSavepointData{}
if err := json.Unmarshal(couchDoc.JSONValue, &savepointDoc); err != nil {
err = errors.Wrap(err, "failed to unmarshal savepoint data")
logger.Errorf("%+v", err)
return nil, err
}
return &version.Height{BlockNum: savepointDoc.BlockNum, TxNum: savepointDoc.TxNum}, nil
}
func validateValue(value []byte) error {
isJSON, jsonVal := tryCastingToJSON(value)
if !isJSON {
return nil
}
return jsonVal.checkReservedFieldsNotPresent()
}
func validateKey(key string) error {
if !utf8.ValidString(key) {
return errors.Errorf("invalid key [%x], must be a UTF-8 string", key)
}
if strings.HasPrefix(key, "_") {
return errors.Errorf("invalid key [%s], cannot begin with \"_\"", key)
}
if key == "" {
return errors.New("invalid key. Empty string is not supported as a key by couchdb")
}
return nil
}
// removeJSONRevision removes the "_rev" if this is a JSON
func removeJSONRevision(jsonValue *[]byte) error {
jsonVal, err := castToJSON(*jsonValue)
if err != nil {
logger.Errorf("Failed to unmarshal couchdb JSON data: %+v", err)
return err
}
jsonVal.removeRevField()
if *jsonValue, err = jsonVal.toBytes(); err != nil {
logger.Errorf("Failed to marshal couchdb JSON data: %+v", err)
}
return err
}