/
queries.go
92 lines (70 loc) · 1.61 KB
/
queries.go
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package datastore
import (
"context"
"errors"
"cloud.google.com/go/datastore"
"google.golang.org/api/iterator"
)
func KeysQuery(ctx context.Context, client *datastore.Client, query *datastore.Query) ([]*datastore.Key, *datastore.Cursor, error) {
it := client.Run(ctx, query)
keys := make([]*datastore.Key, 0)
for {
key, err := it.Next(nil)
if errors.Is(err, iterator.Done) {
break
}
if err != nil {
return keys, nil, err
}
keys = append(keys, key)
}
cursor, err := it.Cursor()
if err != nil {
return keys, nil, err
}
return keys, &cursor, nil
}
func ListQuery(
ctx context.Context,
client *datastore.Client,
query *datastore.Query,
generator func() interface{},
) ([]interface{}, *datastore.Cursor, error) {
it := client.Run(ctx, query)
entities := make([]interface{}, 0)
for {
entity := generator()
_, err := it.Next(entity)
if errors.Is(err, iterator.Done) {
break
}
if _, ok := err.(*datastore.ErrFieldMismatch); ok {
entities = append(entities, entity)
continue
}
if err != nil {
return entities, nil, err
}
entities = append(entities, entity)
}
cursor, err := it.Cursor()
if err != nil {
return entities, nil, err
}
return entities, &cursor, nil
}
func Exists(ctx context.Context, client *datastore.Client, namespace string, kind string, key *datastore.Key) (bool, error) {
query := datastore.
NewQuery(kind).
KeysOnly().
Filter("__key__ =", key).
Limit(1)
if namespace != "" {
query = query.Namespace(namespace)
}
keys, _, err := KeysQuery(ctx, client, query)
if err != nil {
return false, err
}
return len(keys) > 0, nil
}