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package dynamodb
import (
"errors"
"fmt"
simplejson "github.com/bitly/go-simplejson"
)
type Query interface {
Marshal() ([]byte, error)
}
type ScanQuery interface {
Query
AddExclusiveStartKey(key StartKey) error
AddExclusiveStartTableName(table string) error
}
func (t *Table) Query(attributeComparisons []AttributeComparison) ([]map[string]*Attribute, error) {
q := NewQuery(t)
q.AddKeyConditions(attributeComparisons)
return RunQuery(q, t)
}
func (t *Table) QueryOnIndex(attributeComparisons []AttributeComparison, indexName string) ([]map[string]*Attribute, error) {
q := NewQuery(t)
q.AddKeyConditions(attributeComparisons)
q.AddIndex(indexName)
return RunQuery(q, t)
}
func (t *Table) LimitedQuery(attributeComparisons []AttributeComparison, limit int64) ([]map[string]*Attribute, error) {
q := NewQuery(t)
q.AddKeyConditions(attributeComparisons)
q.AddLimit(limit)
return RunQuery(q, t)
}
func (t *Table) LimitedQueryOnIndex(attributeComparisons []AttributeComparison, indexName string, limit int64) ([]map[string]*Attribute, error) {
q := NewQuery(t)
q.AddKeyConditions(attributeComparisons)
q.AddIndex(indexName)
q.AddLimit(limit)
return RunQuery(q, t)
}
func (t *Table) CountQuery(attributeComparisons []AttributeComparison) (int64, error) {
q := NewQuery(t)
q.AddKeyConditions(attributeComparisons)
q.AddSelect("COUNT")
jsonResponse, err := t.Server.queryServer(target("Query"), q)
if err != nil {
return 0, err
}
json, err := simplejson.NewJson(jsonResponse)
if err != nil {
return 0, err
}
itemCount, err := json.Get("Count").Int64()
if err != nil {
return 0, err
}
return itemCount, nil
}
func (t *Table) QueryTable(q Query) ([]map[string]*Attribute, StartKey, error) {
jsonResponse, err := t.Server.queryServer(target("Query"), q)
if err != nil {
return nil, nil, err
}
json, err := simplejson.NewJson(jsonResponse)
if err != nil {
return nil, nil, err
}
itemCount, err := json.Get("Count").Int()
if err != nil {
message := fmt.Sprintf("Unexpected response %s", jsonResponse)
return nil, nil, errors.New(message)
}
results := make([]map[string]*Attribute, itemCount)
for i, _ := range results {
item, err := json.Get("Items").GetIndex(i).Map()
if err != nil {
message := fmt.Sprintf("Unexpected response %s", jsonResponse)
return nil, nil, errors.New(message)
}
results[i] = parseAttributes(item)
}
var lastEvaluatedKey StartKey
if lastKeyMap := json.Get("LastEvaluatedKey").MustMap(); lastKeyMap != nil {
lastEvaluatedKey = lastKeyMap
}
return results, lastEvaluatedKey, nil
}
func (t *Table) QueryCallbackIterator(attributeComparisons []AttributeComparison, cb func(map[string]*Attribute) error) error {
q := NewQuery(t)
q.AddKeyConditions(attributeComparisons)
return t.QueryTableCallbackIterator(q, cb)
}
func (t *Table) QueryOnIndexCallbackIterator(attributeComparisons []AttributeComparison, indexName string, cb func(map[string]*Attribute) error) error {
q := NewQuery(t)
q.AddKeyConditions(attributeComparisons)
q.AddIndex(indexName)
return t.QueryTableCallbackIterator(q, cb)
}
func (t *Table) LimitedQueryCallbackIterator(attributeComparisons []AttributeComparison, limit int64, cb func(map[string]*Attribute) error) error {
q := NewQuery(t)
q.AddKeyConditions(attributeComparisons)
q.AddLimit(limit)
return t.QueryTableCallbackIterator(q, cb)
}
func (t *Table) LimitedQueryOnIndexCallbackIterator(attributeComparisons []AttributeComparison, indexName string, limit int64, cb func(map[string]*Attribute) error) error {
q := NewQuery(t)
q.AddKeyConditions(attributeComparisons)
q.AddIndex(indexName)
q.AddLimit(limit)
return t.QueryTableCallbackIterator(q, cb)
}
func (t *Table) QueryTableCallbackIterator(query ScanQuery, cb func(map[string]*Attribute) error) error {
for {
results, lastEvaluatedKey, err := t.QueryTable(query)
if err != nil {
return err
}
for _, item := range results {
if err := cb(item); err != nil {
return err
}
}
if lastEvaluatedKey == nil {
break
}
query.AddExclusiveStartKey(lastEvaluatedKey)
}
return nil
}
func RunQuery(q Query, t *Table) ([]map[string]*Attribute, error) {
result, _, err := t.QueryTable(q)
if err != nil {
return nil, err
}
return result, err
}
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