1 // Copyright 2016 Google Inc. All rights reserved. 2 // Use of this source code is governed by the Apache 2.0 3 // license that can be found in the LICENSE file. 4 5 package datastore 6 7 import "golang.org/x/net/context" 8 9 // Datastore kinds for the metadata entities. 10 const ( 11 namespaceKind = "__namespace__" 12 kindKind = "__kind__" 13 propertyKind = "__property__" 14 ) 15 16 // Namespaces returns all the datastore namespaces. 17 func Namespaces(ctx context.Context) ([]string, error) { 18 // TODO(djd): Support range queries. 19 q := NewQuery(namespaceKind).KeysOnly() 20 keys, err := q.GetAll(ctx, nil) 21 if err != nil { 22 return nil, err 23 } 24 // The empty namespace key uses a numeric ID (==1), but luckily 25 // the string ID defaults to "" for numeric IDs anyway. 26 return keyNames(keys), nil 27 } 28 29 // Kinds returns the names of all the kinds in the current namespace. 30 func Kinds(ctx context.Context) ([]string, error) { 31 // TODO(djd): Support range queries. 32 q := NewQuery(kindKind).KeysOnly() 33 keys, err := q.GetAll(ctx, nil) 34 if err != nil { 35 return nil, err 36 } 37 return keyNames(keys), nil 38 } 39 40 // keyNames returns a slice of the provided keys' names (string IDs). 41 func keyNames(keys []*Key) []string { 42 n := make([]string, 0, len(keys)) 43 for _, k := range keys { 44 n = append(n, k.StringID()) 45 } 46 return n 47 } 48 49 // KindProperties returns all the indexed properties for the given kind. 50 // The properties are returned as a map of property names to a slice of the 51 // representation types. The representation types for the supported Go property 52 // types are: 53 // "INT64": signed integers and time.Time 54 // "DOUBLE": float32 and float64 55 // "BOOLEAN": bool 56 // "STRING": string, []byte and ByteString 57 // "POINT": appengine.GeoPoint 58 // "REFERENCE": *Key 59 // "USER": (not used in the Go runtime) 60 func KindProperties(ctx context.Context, kind string) (map[string][]string, error) { 61 // TODO(djd): Support range queries. 62 kindKey := NewKey(ctx, kindKind, kind, 0, nil) 63 q := NewQuery(propertyKind).Ancestor(kindKey) 64 65 propMap := map[string][]string{} 66 props := []struct { 67 Repr []string `datastore:"property_representation"` 68 }{} 69 70 keys, err := q.GetAll(ctx, &props) 71 if err != nil { 72 return nil, err 73 } 74 for i, p := range props { 75 propMap[keys[i].StringID()] = p.Repr 76 } 77 return propMap, nil 78 } 79
