From a06f5353030563395f4b779c89c086f83124dac7 Mon Sep 17 00:00:00 2001
From: Vasiliy Tolstov <v.tolstov@unistack.org>
Date: Thu, 1 Apr 2021 00:30:15 +0300
Subject: [PATCH] util/reflect: add StructURLValues func

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>
---
 util/reflect/reflect.go      | 79 ++++++++++++++++++++++++++++++++++++
 util/reflect/reflect_test.go | 18 ++++++++
 2 files changed, 97 insertions(+)

diff --git a/util/reflect/reflect.go b/util/reflect/reflect.go
index 06cf1087..05659e82 100644
--- a/util/reflect/reflect.go
+++ b/util/reflect/reflect.go
@@ -173,6 +173,79 @@ func CopyFrom(a, b interface{}) {
 	}
 }
 
+func StructURLValues(src interface{}, pref string, tags []string) (url.Values, error) {
+	data := url.Values{}
+
+	sv := reflect.ValueOf(src)
+	if sv.Kind() == reflect.Ptr {
+		sv = sv.Elem()
+	}
+	if sv.Kind() != reflect.Struct {
+		return nil, ErrInvalidStruct
+	}
+
+	typ := sv.Type()
+	for idx := 0; idx < typ.NumField(); idx++ {
+		fld := typ.Field(idx)
+		val := sv.Field(idx)
+		if !val.CanSet() || len(fld.PkgPath) != 0 || !val.IsValid() {
+			continue
+		}
+
+		var t *tag
+		for _, tn := range tags {
+			ts, ok := fld.Tag.Lookup(tn)
+			if !ok {
+				continue
+			}
+
+			tp := strings.Split(ts, ",")
+			// special
+			switch tn {
+			case "protobuf": // special
+				t = &tag{key: tn, name: tp[3][5:], opts: append(tp[:3], tp[4:]...)}
+			default:
+				t = &tag{key: tn, name: tp[0], opts: tp[1:]}
+			}
+			if t.name != "" {
+				break
+			}
+		}
+
+		if t.name == "" {
+			// fallback to lowercase
+			t.name = strings.ToLower(fld.Name)
+		}
+		if pref != "" {
+			t.name = pref + "." + t.name
+		}
+
+		switch val.Kind() {
+		case reflect.Struct, reflect.Ptr:
+			if val.IsNil() {
+				continue
+			}
+			ndata, err := StructURLValues(val.Interface(), t.name, tags)
+			if err != nil {
+				return ndata, err
+			}
+			for k, v := range ndata {
+				data[k] = v
+			}
+		default:
+			switch val.Kind() {
+			case reflect.Slice:
+				for i := 0; i < val.Len(); i++ {
+					data.Add(t.name, fmt.Sprintf("%v", val.Index(i)))
+				}
+			default:
+				data.Set(t.name, fmt.Sprintf("%v", val))
+			}
+		}
+	}
+	return data, nil
+}
+
 // URLMap returns map of url query params
 func URLMap(query string) (map[string]interface{}, error) {
 	var (
@@ -624,3 +697,9 @@ func mergeSliceIface(a []interface{}, b []interface{}) []interface{} {
 	a = append(a, b...)
 	return a
 }
+
+type tag struct {
+	key  string
+	name string
+	opts []string
+}
diff --git a/util/reflect/reflect_test.go b/util/reflect/reflect_test.go
index 7b3e95ae..745943de 100644
--- a/util/reflect/reflect_test.go
+++ b/util/reflect/reflect_test.go
@@ -5,6 +5,24 @@ import (
 	"testing"
 )
 
+func TestStructURLValues(t *testing.T) {
+	type Str struct {
+		Name string `json:"name"`
+		Args []int  `json:"args"`
+		Str  *Str   `json:"str"`
+	}
+
+	val := &Str{Name: "test_name", Args: []int{1, 2, 3}, Str: &Str{Name: "nested_name"}}
+	data, err := StructURLValues(val, "", []string{"json"})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if data.Get("name") != "test_name" {
+		t.Fatalf("invalid data: %v", data)
+	}
+}
+
 func TestURLSliceVars(t *testing.T) {
 	u, err := url.Parse("http://localhost/v1/test/call/my_name?key=arg1&key=arg2&key=arg3")
 	if err != nil {