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package dynamodb
import (
"errors"
"fmt"
"log"
simplejson "github.com/bitly/go-simplejson"
)
func (t *Table) FetchPartialResults(query ScanQuery) ([]map[string]*Attribute, StartKey, error) {
jsonResponse, err := t.Server.queryServer(target("Scan"), query)
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) FetchResultCallbackIterator(query ScanQuery, cb func(map[string]*Attribute) error) error {
for {
results, lastEvaluatedKey, err := t.FetchPartialResults(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 (t *Table) ScanPartial(attributeComparisons []AttributeComparison, exclusiveStartKey StartKey) ([]map[string]*Attribute, StartKey, error) {
return t.ParallelScanPartialLimit(attributeComparisons, exclusiveStartKey, 0, 0, 0)
}
func (t *Table) ScanPartialLimit(attributeComparisons []AttributeComparison, exclusiveStartKey StartKey, limit int64) ([]map[string]*Attribute, StartKey, error) {
return t.ParallelScanPartialLimit(attributeComparisons, exclusiveStartKey, 0, 0, limit)
}
func (t *Table) ParallelScanPartial(attributeComparisons []AttributeComparison, exclusiveStartKey StartKey, segment, totalSegments int) ([]map[string]*Attribute, StartKey, error) {
return t.ParallelScanPartialLimit(attributeComparisons, exclusiveStartKey, segment, totalSegments, 0)
}
func (t *Table) ParallelScanPartialLimit(attributeComparisons []AttributeComparison, exclusiveStartKey StartKey, segment, totalSegments int, limit int64) ([]map[string]*Attribute, StartKey, error) {
q := NewQuery(t)
q.AddScanFilter(attributeComparisons)
if exclusiveStartKey != nil {
q.AddExclusiveStartKey(exclusiveStartKey)
}
if totalSegments > 0 {
q.AddParallelScanConfiguration(segment, totalSegments)
}
if limit > 0 {
q.AddLimit(limit)
}
return t.FetchPartialResults(q)
}
func (t *Table) FetchResults(query ScanQuery) ([]map[string]*Attribute, error) {
results, _, err := t.FetchPartialResults(query)
return results, err
}
func (t *Table) Scan(attributeComparisons []AttributeComparison) ([]map[string]*Attribute, error) {
q := NewQuery(t)
q.AddScanFilter(attributeComparisons)
return t.FetchResults(q)
}
func (t *Table) ParallelScan(attributeComparisons []AttributeComparison, segment int, totalSegments int) ([]map[string]*Attribute, error) {
q := NewQuery(t)
q.AddScanFilter(attributeComparisons)
q.AddParallelScanConfiguration(segment, totalSegments)
return t.FetchResults(q)
}
func (t *Table) ScanCallbackIterator(attributeComparisons []AttributeComparison, cb func(map[string]*Attribute) error) error {
q := NewQuery(t)
q.AddScanFilter(attributeComparisons)
return t.FetchResultCallbackIterator(q, cb)
}
func parseKey(t *Table, s map[string]interface{}) *Key {
k := &Key{}
hk := t.Key.KeyAttribute
if v, ok := s[hk.Name].(map[string]interface{}); ok {
switch hk.Type {
case TYPE_NUMBER, TYPE_STRING, TYPE_BINARY:
if key, ok := v[hk.Type].(string); ok {
k.HashKey = key
} else {
log.Printf("type assertion to string failed for : %s\n", hk.Type)
return nil
}
default:
log.Printf("invalid primary key hash type : %s\n", hk.Type)
return nil
}
} else {
log.Printf("type assertion to map[string]interface{} failed for : %s\n", hk.Name)
return nil
}
if t.Key.HasRange() {
rk := t.Key.RangeAttribute
if v, ok := s[rk.Name].(map[string]interface{}); ok {
switch rk.Type {
case TYPE_NUMBER, TYPE_STRING, TYPE_BINARY:
if key, ok := v[rk.Type].(string); ok {
k.RangeKey = key
} else {
log.Printf("type assertion to string failed for : %s\n", rk.Type)
return nil
}
default:
log.Printf("invalid primary key range type : %s\n", rk.Type)
return nil
}
} else {
log.Printf("type assertion to map[string]interface{} failed for : %s\n", rk.Name)
return nil
}
}
return k
}
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