refactor: new persistence, more SQL, less ORM

persistence/helpers.go

@@ -0,0 +1,62 @@
+package persistence
+
+import (
+	"encoding/json"
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+func toSqlArgs(rec interface{}) (map[string]interface{}, error) {
+	// Convert to JSON...
+	b, err := json.Marshal(rec)
+	if err != nil {
+		return nil, err
+	}
+
+	// ... then convert to map
+	var m map[string]interface{}
+	err = json.Unmarshal(b, &m)
+	r := make(map[string]interface{}, len(m))
+	for f, v := range m {
+		r[toSnakeCase(f)] = v
+	}
+	return r, err
+}
+
+var matchFirstCap = regexp.MustCompile("(.)([A-Z][a-z]+)")
+var matchAllCap = regexp.MustCompile("([a-z0-9])([A-Z])")
+
+func toSnakeCase(str string) string {
+	snake := matchFirstCap.ReplaceAllString(str, "${1}_${2}")
+	snake = matchAllCap.ReplaceAllString(snake, "${1}_${2}")
+	return strings.ToLower(snake)
+}
+
+func ToStruct(m map[string]interface{}, rec interface{}, fieldNames []string) error {
+	var r = make(map[string]interface{}, len(m))
+	for _, f := range fieldNames {
+		v, ok := m[f]
+		if !ok {
+			return fmt.Errorf("invalid field '%s'", f)
+		}
+		r[toCamelCase(f)] = v
+	}
+	// Convert to JSON...
+	b, err := json.Marshal(r)
+	if err != nil {
+		return err
+	}
+
+	// ... then convert to struct
+	err = json.Unmarshal(b, &rec)
+	return err
+}
+
+var matchUnderscore = regexp.MustCompile("_([A-Za-z])")
+
+func toCamelCase(str string) string {
+	return matchUnderscore.ReplaceAllStringFunc(str, func(s string) string {
+		return strings.ToUpper(strings.Replace(s, "_", "", -1))
+	})
+}