move common code to pkg

pkg/errors.go

@@ -0,0 +1,6 @@
+package pkg
+
+var (
+	SQLSTATE_25P02 = "25P02"
+	SQLSTATE_23505 = "23505"
+)

pkg/go.mod

@@ -0,0 +1,3 @@
+module pkg
+
+go 1.25.2

pkg/handlers.go

@@ -0,0 +1,36 @@
+package pkg
+
+import (
+	"encoding/json"
+	"net/http"
+	"strconv"
+)
+
+type (
+	BaseHandler struct{}
+)
+
+func (bh *BaseHandler) ToJSON(w http.ResponseWriter, statusCode int, data any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(statusCode)
+	json.NewEncoder(w).Encode(data)
+}
+
+func (bh *BaseHandler) ParamToInt(param string, defaultValue ...int) int {
+	if param == "" {
+		if len(defaultValue) > 0 {
+			return defaultValue[0]
+		}
+		return 0
+	}
+
+	value, err := strconv.Atoi(param)
+	if err != nil {
+		if len(defaultValue) > 0 {
+			return defaultValue[0]
+		}
+		return 0
+	}
+
+	return value
+}