I have a json object sent from a mobile application, looks like this:
{
"product_id": "0123456789",
"name": "PRODUCT_NAME",
"manufacturer": "PRODUCT_MANUFACTURER",
"image_url": "IMAGE_URL",
"additional_info": "",
"store_id": "STORE_ID",
"store_name": "STORE_NAME",
"owner_id": "OWNER_ID",
"quantities": {
"1000": 10.0,
"1500": 12.0,
}
}
The key value in quantities is a for example, can be grams, and the value is a representes a price.
So for example, 1000 grams of rice will cost 10$, and 1500 grams of rice will cost 12.0$ (as a sale or something)
I have a Model Object in my Go code, that has the quantities filed as map[int]float32
I'm trying to find a way to insert this map into a PostgreSQL database I have, but can't figure out how.
This is my Go Model:
type Product struct {
ID string
UUID string
Name string
Manufacturer string
ImageURL string
AdditionalInfo string
StoreID string
StoreName string
OwnerID string
Quantities map[int]float32
}
I read about JSONB but won't it return a json when I retrieve the data? I need it to return a map[int]float32 and not json.
You need to implement driver.Valuer and sql.Scanner interface for save as JSONB
The driver.Valuer interface, such that it marshals the object into a JSON byte slice that can be understood by the database.
The sql.Scanner interface, such that it unmarshals a JSON byte slice from the database into the struct fields.
And for json Marshal you need to convert map[int]float32 into map[string]float32
type cusjsonb map[int]float32
// Returns the JSON-encoded representation
func (a cusjsonb) Value() (driver.Value, error) {
// Convert to map[string]float32 from map[int]float32
x := make(map[string]float32)
for k, v := range a {
x[strconv.FormatInt(int64(k), 10)] = v
}
// Marshal into json
return json.Marshal(x)
}
// Decodes a JSON-encoded value
func (a *cusjsonb) Scan(value interface{}) error {
b, ok := value.([]byte)
if !ok {
return errors.New("type assertion to []byte failed")
}
// Unmarshal from json to map[string]float32
x := make(map[string]float32)
if err := json.Unmarshal(b, &x); err != nil {
return err
}
// Convert to map[int]float32 from map[string]float32
*a = make(cusjsonb, len(x))
for k, v := range x {
if ki, err := strconv.ParseInt(k, 10, 32); err != nil {
return err
} else {
(*a)[int(ki)] = v
}
}
return nil
}