1// Copyright 2019 Google LLC 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15package datastore 16 17import ( 18 "encoding/base64" 19 "strings" 20 21 "cloud.google.com/go/datastore/internal/gaepb" 22 "github.com/golang/protobuf/proto" 23) 24 25// decodeGAEKey attempts to decode the given encoded key generated by the 26// GAE Datastore package (google.golang.org/appengine/datastore), returning nil 27// if the key couldn't be decoded. 28func decodeGAEKey(encoded string) *Key { 29 // Re-add padding. 30 if m := len(encoded) % 4; m != 0 { 31 encoded += strings.Repeat("=", 4-m) 32 } 33 34 b, err := base64.URLEncoding.DecodeString(encoded) 35 if err != nil { 36 return nil 37 } 38 ref := new(gaepb.Reference) 39 if err := proto.Unmarshal(b, ref); err != nil { 40 return nil 41 } 42 return gaeProtoToKey(ref) 43} 44 45// gaeProtoToKey accepts a GAE Datastore key and converts it to a Cloud Datastore key. 46// This is adapted from the "protoToKey" function in the appengine/datastore package. 47// 48// NOTE(cbro): this is a lossy operation, as GAE Datastore keys include the project/app ID, 49// but Cloud Datastore keys do not. 50func gaeProtoToKey(r *gaepb.Reference) *Key { 51 namespace := r.GetNameSpace() 52 var k *Key 53 for _, e := range r.Path.Element { 54 k = &Key{ 55 Kind: e.GetType(), 56 Name: e.GetName(), 57 ID: e.GetId(), 58 Parent: k, 59 Namespace: namespace, 60 } 61 } 62 if !k.valid() { 63 return nil 64 } 65 return k 66} 67