app-cloudep-trade-service/internal/lib/mongo/custom_mongo_decimal.go

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package mongo
import (
"fmt"
"reflect"
"github.com/shopspring/decimal"
"go.mongodb.org/mongo-driver/bson/bsoncodec"
"go.mongodb.org/mongo-driver/bson/bsonrw"
"go.mongodb.org/mongo-driver/bson/primitive"
)
type MgoDecimal struct{}
var (
_ bsoncodec.ValueEncoder = &MgoDecimal{}
_ bsoncodec.ValueDecoder = &MgoDecimal{}
)
func (dc *MgoDecimal) EncodeValue(_ bsoncodec.EncodeContext, w bsonrw.ValueWriter, value reflect.Value) error {
// TODO 待確認是否有非decimal.Decimal type而導致error的場景
dec, ok := value.Interface().(decimal.Decimal)
if !ok {
return fmt.Errorf("value %v to encode is not of type decimal.Decimal", value)
}
// Convert decimal.Decimal to primitive.Decimal128.
primDec, err := primitive.ParseDecimal128(dec.String())
if err != nil {
return fmt.Errorf("converting decimal.Decimal %v to primitive.Decimal128 error: %w", dec, err)
}
return w.WriteDecimal128(primDec)
}
func (dc *MgoDecimal) DecodeValue(_ bsoncodec.DecodeContext, r bsonrw.ValueReader, value reflect.Value) error {
primDec, err := r.ReadDecimal128()
if err != nil {
return fmt.Errorf("reading primitive.Decimal128 from ValueReader error: %w", err)
}
// Convert primitive.Decimal128 to decimal.Decimal.
dec, err := decimal.NewFromString(primDec.String())
if err != nil {
return fmt.Errorf("converting primitive.Decimal128 %v to decimal.Decimal error: %w", primDec, err)
}
// set as decimal.Decimal type
value.Set(reflect.ValueOf(dec))
return nil
}