Fix for aws#2920

feature/dynamodb/attributevalue/decode.go

@@ -2,6 +2,8 @@ package attributevalue
 
 import (
 	"encoding"
+	"encoding/base64"
+	"encoding/json"
 	"fmt"
 	"reflect"
 	"strconv"
@@ -1049,3 +1051,117 @@ func defaultDecodeTimeS(v string) (time.Time, error) {
 func defaultDecodeTimeN(v string) (time.Time, error) {
 	return decodeUnixTime(v)
 }
+
+func parseAttributeValue(raw map[string]json.RawMessage) (types.AttributeValue, error) {
+	for k, v := range raw {
+		switch k {
+		case "SS":
+			var ss []string
+			if err := json.Unmarshal(v, &ss); err != nil {
+				return nil, err
+			}
+			return &types.AttributeValueMemberSS{Value: ss}, nil
+		case "NS":
+			var ns []string
+			if err := json.Unmarshal(v, &ns); err != nil {
+				return nil, err
+			}
+			return &types.AttributeValueMemberNS{Value: ns}, nil
+		case "B":
+			var b64 string
+			if err := json.Unmarshal(v, &b64); err != nil {
+				return nil, err
+			}
+			decoded, err := base64.StdEncoding.DecodeString(b64)
+			if err != nil {
+				return nil, fmt.Errorf("failed to decode base64 for B: %w", err)
+			}
+			return &types.AttributeValueMemberB{Value: decoded}, nil
+		case "BS":
+			var bs []string
+			if err := json.Unmarshal(v, &bs); err != nil {
+				return nil, err
+			}
+
+			decodedBS := make([][]byte, len(bs))
+			for i, b64 := range bs {
+				decoded, err := base64.StdEncoding.DecodeString(b64)
+				if err != nil {
+					return nil, fmt.Errorf("failed to decode base64 for BS: %w", err)
+				}
+				decodedBS[i] = decoded
+			}
+			return &types.AttributeValueMemberBS{Value: decodedBS}, nil
+		case "S":
+			var s string
+			if err := json.Unmarshal(v, &s); err != nil {
+				return nil, err
+			}
+			return &types.AttributeValueMemberS{Value: s}, nil
+		case "N":
+			var n string
+			if err := json.Unmarshal(v, &n); err != nil {
+				return nil, err
+			}
+			return &types.AttributeValueMemberN{Value: n}, nil
+		case "BOOL":
+			var b bool
+			if err := json.Unmarshal(v, &b); err != nil {
+				return nil, err
+			}
+			return &types.AttributeValueMemberBOOL{Value: b}, nil
+		case "NULL":
+			return &types.AttributeValueMemberNULL{Value: true}, nil
+		case "L":
+			var list []map[string]json.RawMessage
+			if err := json.Unmarshal(v, &list); err != nil {
+				return nil, err
+			}
+			var attrList []types.AttributeValue
+			for _, item := range list {
+				attr, err := parseAttributeValue(item)
+				if err != nil {
+					return nil, err
+				}
+				attrList = append(attrList, attr)
+			}
+			return &types.AttributeValueMemberL{Value: attrList}, nil
+		case "M":
+			var m map[string]map[string]json.RawMessage
+			if err := json.Unmarshal(v, &m); err != nil {
+				return nil, err
+			}
+			attrMap := make(map[string]types.AttributeValue)
+			for mk, mv := range m {
+				attr, err := parseAttributeValue(mv)
+				if err != nil {
+					return nil, err
+				}
+				attrMap[mk] = attr
+			}
+			return &types.AttributeValueMemberM{Value: attrMap}, nil
+		default:
+			return nil, fmt.Errorf("unsupported type: %s", k)
+		}
+	}
+	return nil, fmt.Errorf("empty attribute value")
+}
+
+func UnmarshalDynamoDBFromJSON(jsonStr []byte) (map[string]types.AttributeValue, error) {
+	var raw map[string]map[string]json.RawMessage
+	err := json.Unmarshal(jsonStr, &raw)
+	if err != nil {
+		return nil, err
+	}
+
+	result := make(map[string]types.AttributeValue)
+	for key, value := range raw {
+		attr, err := parseAttributeValue(value)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse key %s: %w", key, err)
+		}
+		result[key] = attr
+	}
+
+	return result, nil
+}

feature/dynamodb/attributevalue/decode_test.go

@@ -1,6 +1,7 @@
 package attributevalue
 
 import (
+	"encoding/base64"
 	"fmt"
 	"reflect"
 	"strconv"
@@ -1344,3 +1345,97 @@ func TestUnmarshalIndividualSetValues(t *testing.T) {
 		t.Errorf("expect value match\n%s", diff)
 	}
 }
+
+func TestUnmarshalDynamoDBJSON(t *testing.T) {
+	msg1 := "Dynamo"
+	msg2 := "DynamoDB"
+
+	bin1 := make([]byte, base64.StdEncoding.EncodedLen(len(msg1)))
+	bin2 := make([]byte, base64.StdEncoding.EncodedLen(len(msg2)))
+
+	base64.StdEncoding.Encode(bin1, []byte(msg1))
+	base64.StdEncoding.Encode(bin2, []byte(msg2))
+
+	actual, err := UnmarshalDynamoDBFromJSON(
+		[]byte(fmt.Sprintf(`{
+		"Name": {"S": "Alice"},
+		"Age": {"N": "30"},
+		"IsActive": {"BOOL": true},
+		"Metadata": {"M": {"Key": {"S": "Value"}}},
+		"Tags": {"L": [{"S": "tag1"}, {"S": "tag2"}]},
+		"StringSet": {"SS": ["one", "two", "three"]},
+		"NumberSet": {"NS": ["10", "20", "30"]},
+		"Binary": {"B": "%s"},
+		"BinarySet": {"BS": ["%s", "%s"]}
+	}`, bin1, bin1, bin2),
+		))
+	if err != nil {
+		t.Fatalf("expect no error, got %v", err)
+	}
+
+	if diff := cmpDiff(
+		&types.AttributeValueMemberS{Value: "Alice"},
+		actual["Name"]); diff != "" {
+		t.Errorf("expect value match\n%s", diff)
+	}
+
+	if diff := cmpDiff(
+		&types.AttributeValueMemberN{Value: "30"},
+		actual["Age"]); diff != "" {
+		t.Errorf("expect value match\n%s", diff)
+	}
+
+	if diff := cmpDiff(
+		&types.AttributeValueMemberBOOL{Value: true},
+		actual["IsActive"]); diff != "" {
+		t.Errorf("expect value match\n%s", diff)
+	}
+
+	if diff := cmpDiff(
+		&types.AttributeValueMemberM{
+			Value: map[string]types.AttributeValue{
+				"Key": &types.AttributeValueMemberS{Value: "Value"},
+			},
+		},
+		actual["Metadata"]); diff != "" {
+		t.Errorf("expect value match\n%s", diff)
+	}
+
+	if diff := cmpDiff(
+		&types.AttributeValueMemberL{Value: []types.AttributeValue{
+			&types.AttributeValueMemberS{Value: "tag1"},
+			&types.AttributeValueMemberS{Value: "tag2"},
+		},
+		},
+		actual["Tags"]); diff != "" {
+		t.Errorf("expect value match\n%s", diff)
+	}
+
+	if diff := cmpDiff(
+		&types.AttributeValueMemberSS{Value: []string{"one", "two", "three"}},
+		actual["StringSet"]); diff != "" {
+		t.Errorf("expect value match\n%s", diff)
+	}
+	if diff := cmpDiff(
+		&types.AttributeValueMemberNS{Value: []string{"10", "20", "30"}},
+		actual["NumberSet"]); diff != "" {
+		t.Errorf("expect value match\n%s", diff)
+	}
+
+	if diff := cmpDiff(
+		&types.AttributeValueMemberB{Value: []byte(msg1)},
+		actual["Binary"]); diff != "" {
+		t.Errorf("expect value match\n%s", diff)
+	}
+
+	if diff := cmpDiff(
+		&types.AttributeValueMemberBS{Value: [][]byte{
+			[]byte(msg1),
+			[]byte(msg2),
+		},
+		},
+		actual["BinarySet"]); diff != "" {
+		t.Errorf("expect value match\n%s", diff)
+	}
+
+}