/
mapped.go
98 lines (94 loc) · 2.97 KB
/
mapped.go
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package ddb
import (
"encoding/json"
"fmt"
"github.com/aws/aws-sdk-go-v2/service/dynamodb/types"
ddbv1 "github.com/crewlinker/protoc-gen-dynamodb/proto/ddb/v1"
"google.golang.org/protobuf/encoding/protojson"
)
// UnmarshalMappedMessage decodes the dynamodb representation of a map of messages
func UnmarshalMappedMessage[K comparable, T any, TP ProtoMessage[T]](m types.AttributeValue, fv func(s string) (K, error), os ...Option) (xm map[K]TP, err error) {
opts := applyOptions(os...)
switch opts.embedEncoding {
case ddbv1.Encoding_ENCODING_JSON:
var outer map[string]json.RawMessage
if err := jsonUnmarshal(m, &outer); err != nil {
return nil, fmt.Errorf("failed to unmarshal outer map: %w", err)
}
xm = make(map[K]TP)
for k, b := range outer {
kv, err := fv(k)
if err != nil {
return nil, fmt.Errorf("failed to unmarshal map key: %w", err)
}
var mv TP = new(T)
if err := protojson.Unmarshal(b, mv); err != nil {
return nil, fmt.Errorf("failed to unmarshal mapped message '%s': %w", k, err)
}
xm[kv] = mv
}
return
case ddbv1.Encoding_ENCODING_DYNAMO:
xm = make(map[K]TP)
mm, ok := m.(*types.AttributeValueMemberM)
if !ok {
return nil, fmt.Errorf("failed to unmarshal mapped field: no map attribute provided")
}
for k, v := range mm.Value {
kv, err := fv(k)
if err != nil {
return nil, fmt.Errorf("failed to unmarshal map key: %w", err)
}
if _, ok := v.(*types.AttributeValueMemberNULL); ok {
xm[kv] = nil // set explicit nil
continue
}
var mv TP = new(T)
if err = UnmarshalMessage(v, mv, os...); err != nil {
return nil, fmt.Errorf("failed to unmarshal message map value: %w", err)
}
xm[kv] = mv
}
return
default:
return nil, errEmbedEncoding()
}
}
// MarshalMappedMessage takes a map of messages and marshals it to a dynamodb representation
func MarshalMappedMessage[K comparable, T any, TP ProtoMessage[T]](x map[K]TP, os ...Option) (types.AttributeValue, error) {
opts := applyOptions(os...)
switch opts.embedEncoding {
case ddbv1.Encoding_ENCODING_JSON:
outer := make(map[string]json.RawMessage, len(x))
for k, v := range x {
kv, err := marshalMapKey(k)
if err != nil {
return nil, fmt.Errorf("failed to marshal map key: %w", err)
}
if outer[kv], err = protojson.Marshal(v); err != nil {
return nil, fmt.Errorf("failed to marshal mapped message '%s': %w", kv, err)
}
}
return jsonMarshal(outer)
case ddbv1.Encoding_ENCODING_DYNAMO:
m := &types.AttributeValueMemberM{Value: make(map[string]types.AttributeValue)}
for k, v := range x {
kv, err := marshalMapKey(k)
if err != nil {
return nil, fmt.Errorf("failed to marshal map key: %w", err)
}
if v == nil {
m.Value[kv] = &types.AttributeValueMemberNULL{Value: true}
continue
}
mv, err := MarshalMessage(v, os...)
if err != nil {
return nil, fmt.Errorf("failed to marshal mapped message: %w", err)
}
m.Value[kv] = mv
}
return m, nil
default:
return nil, errEmbedEncoding()
}
}