chore: custom error

internal/handlers/restutil/params.go

@@ -0,0 +1,24 @@
+package restutil
+
+import (
+	"fmt"
+	"net/http"
+	"strconv"
+)
+
+func IntParam(r *http.Request, key string) (val int, err error) {
+	str := r.URL.Query().Get(key)
+	if str == "" {
+		return
+	}
+
+	val, err = strconv.Atoi(str)
+	if err != nil {
+		err = WrappErr(
+			err,
+			ErrorTypeValidation,
+			fmt.Sprintf("failed to parse query parameter '%s': not an int", key),
+		)
+	}
+	return
+}