reflect code

reflectcode.go

// old 
func getPreferredProductRefIdsFromContactProgress(contactProgress models.ContactProgress) []int {
	if !contactProgress.IsEmpty() {
		enterInfo := contactProgress.EnterInfo
		enterInfoMap := make(map[string]interface{})
		json.Unmarshal([]byte(enterInfo), &enterInfoMap)
		if enterInfoMap["product_ref_ids"] != nil {
			value := reflect.ValueOf(enterInfoMap["product_ref_ids"])
			fmt.Println(value.Kind(), enterInfoMap["product_ref_ids"])
			var rawData string
			var productRefId []int

			if value.Kind() == reflect.String {
				rawData = enterInfoMap["product_ref_ids"].(string)
				rawData = strings.Replace(rawData, "\"", "", -1)
				json.Unmarshal([]byte(rawData), &productRefId)
			} else {
				for i := 0; i < value.Len(); i++ {
					str := value.Index(i).Interface().(string)
					refId, _ := strconv.Atoi(str)
					productRefId = append(productRefId, refId)
				}
			}
			return productRefId

		}
	}
	return
}

// new 

func getPreferredProductRefIdsFromContactProgress(contactProgress models.ContactProgress) ([]int, error) {

	if contactProgress.IsEmpty() {
		return nil, nil
	}

	// generate the map for parsing the initial json document
	enterInfo := make(map[string]interface{})

	err := json.Unmarshal([]byte(contactProgress.EnterInfo), &enterInfo)

	// parse the document, get the error
	if err != nil {
		return nil, err
	}

	// get the value of the enterInfo["product_ref_ids"]
	// and the 'ok' value to know whatever the key exists
	productRefIDs, ok := enterInfo["product_ref_ids"]

	if !ok {
		return nil, errors.New("no product_ref_ids key found in JSON")
	}

	return parseProductRefIDs(productRefIDs)
}

func parseProductRefIDs(productRefIDs interface{}) ([]int, error) {
	var productRefIDsSlice []int
	// detect productRefIDs type
	// sometimes has string or slice
	v := reflect.ValueOf(productRefIDs)

	switch v.Kind() {

	case reflect.String:
		// remove " symbol if exits
		cleanProductRefIDs := strings.Replace(productRefIDs.(string), "\"", "", -1)

		// parse the product_ref_ids valus as JSON and capture this error
		err := json.Unmarshal([]byte(cleanProductRefIDs), &productRefIDsSlice)

		if err != nil {
			return nil, err
		}

		// create an []int with 0 items in it,
		// but enought memory allocated to hold the number of elements in productRefIDsSlice
		ids := make([]int, 0, len(productRefIDsSlice))

		for _, id := range productRefIDsSlice {
			ids = append(ids, id)
		}

		// return the result ids slice
		return ids, nil

	case reflect.Slice:

		// create an []int with 0 items in it.
		ids := make([]int, 0, v.Len())

		for i := 0; i < v.Len(); i++ {
			// get string id item in v
			idStr := v.Index(i).Interface().(string)

			id, _ := strconv.Atoi(idStr)

			ids = append(ids, id)
		}
		// return ids result ids slice
		return ids, nil

	default:
		return nil, nil
	}
}