add form for codec (#1158)

* add form for http codec

encoding/form/proto_encode.go

@@ -0,0 +1,187 @@
+package form
+
+import (
+	"encoding/base64"
+	"fmt"
+	"net/url"
+	"reflect"
+	"strconv"
+	"strings"
+	"time"
+
+	"google.golang.org/genproto/protobuf/field_mask"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/types/known/durationpb"
+	"google.golang.org/protobuf/types/known/timestamppb"
+	"google.golang.org/protobuf/types/known/wrapperspb"
+)
+
+// EncodeMap encode proto message to url query.
+func EncodeMap(msg proto.Message) (url.Values, error) {
+	if msg == nil || (reflect.ValueOf(msg).Kind() == reflect.Ptr && reflect.ValueOf(msg).IsNil()) {
+		return url.Values{}, nil
+	}
+	u := make(url.Values)
+	err := encodeByField(u, "", msg.ProtoReflect())
+	if err != nil {
+		return nil, err
+	}
+	return u, nil
+}
+
+func encodeByField(u url.Values, path string, v protoreflect.Message) error {
+	for i := 0; i < v.Descriptor().Fields().Len(); i++ {
+		fd := v.Descriptor().Fields().Get(i)
+		var key string
+		var newPath string
+		if fd.HasJSONName() {
+			key = fd.JSONName()
+		} else {
+			key = fd.TextName()
+		}
+		if path == "" {
+			newPath = key
+		} else {
+			newPath = path + "." + key
+		}
+
+		if of := fd.ContainingOneof(); of != nil {
+			if f := v.WhichOneof(of); f != nil {
+				if f != fd {
+					continue
+				}
+			}
+			continue
+		}
+		switch {
+		case fd.IsList():
+			if v.Get(fd).List().Len() > 0 {
+				list, err := encodeRepeatedField(fd, v.Get(fd).List())
+				if err != nil {
+					return err
+				}
+				u[newPath] = list
+			}
+		case fd.IsMap():
+			if v.Get(fd).Map().Len() > 0 {
+				m, err := encodeMapField(fd, v.Get(fd).Map())
+				if err != nil {
+					return err
+				}
+				for k, value := range m {
+					u[fmt.Sprintf("%s[%s]", newPath, k)] = []string{value}
+				}
+			}
+		case (fd.Kind() == protoreflect.MessageKind) || (fd.Kind() == protoreflect.GroupKind):
+			value, err := encodeMessage(fd.Message(), v.Get(fd))
+			if err == nil {
+				u[newPath] = []string{value}
+				continue
+			}
+			err = encodeByField(u, newPath, v.Get(fd).Message())
+			if err != nil {
+				return err
+			}
+		default:
+			value, err := encodeField(fd, v.Get(fd))
+			if err != nil {
+				return err
+			}
+			u[newPath] = []string{value}
+		}
+	}
+
+	return nil
+}
+
+func encodeRepeatedField(fieldDescriptor protoreflect.FieldDescriptor, list protoreflect.List) ([]string, error) {
+	var values []string
+	for i := 0; i < list.Len(); i++ {
+		value, err := encodeField(fieldDescriptor, list.Get(i))
+		if err != nil {
+			return nil, err
+		}
+		values = append(values, value)
+	}
+
+	return values, nil
+}
+
+func encodeMapField(fieldDescriptor protoreflect.FieldDescriptor, mp protoreflect.Map) (map[string]string, error) {
+	m := make(map[string]string)
+	mp.Range(func(k protoreflect.MapKey, v protoreflect.Value) bool {
+		key, err := encodeField(fieldDescriptor.MapValue(), k.Value())
+		if err != nil {
+			return false
+		}
+		value, err := encodeField(fieldDescriptor.MapValue(), v)
+		if err != nil {
+			return false
+		}
+		m[key] = value
+		return true
+	})
+
+	return m, nil
+}
+
+func encodeField(fieldDescriptor protoreflect.FieldDescriptor, value protoreflect.Value) (string, error) {
+	switch fieldDescriptor.Kind() {
+	case protoreflect.BoolKind:
+		return strconv.FormatBool(value.Bool()), nil
+	case protoreflect.EnumKind:
+		if fieldDescriptor.Enum().FullName() == "google.protobuf.NullValue" {
+			return "null", nil
+		}
+		desc := fieldDescriptor.Enum().Values().ByNumber(value.Enum())
+		return string(desc.Name()), nil
+	case protoreflect.StringKind:
+		return value.String(), nil
+	case protoreflect.BytesKind:
+		return base64.URLEncoding.EncodeToString(value.Bytes()), nil
+	case protoreflect.MessageKind, protoreflect.GroupKind:
+		return encodeMessage(fieldDescriptor.Message(), value)
+	default:
+		return fmt.Sprintf("%v", value.Interface()), nil
+	}
+}
+
+// marshalMessage marshals the fields in the given protoreflect.Message.
+// If the typeURL is non-empty, then a synthetic "@type" field is injected
+// containing the URL as the value.
+func encodeMessage(msgDescriptor protoreflect.MessageDescriptor, value protoreflect.Value) (string, error) {
+	switch msgDescriptor.FullName() {
+	case "google.protobuf.Timestamp":
+		t, ok := value.Interface().(*timestamppb.Timestamp)
+		if !ok {
+			return "", nil
+		}
+		return t.AsTime().Format(time.RFC3339Nano), nil
+	case "google.protobuf.Duration":
+		d, ok := value.Interface().(*durationpb.Duration)
+		if !ok {
+			return "", nil
+		}
+		return d.AsDuration().String(), nil
+	case "google.protobuf.BytesValue":
+		b, ok := value.Interface().(*wrapperspb.BytesValue)
+		if !ok {
+			return "", nil
+		}
+		return base64.StdEncoding.EncodeToString(b.Value), nil
+	case "google.protobuf.DoubleValue", "google.protobuf.FloatValue", "google.protobuf.Int64Value", "google.protobuf.Int32Value",
+		"google.protobuf.UInt64Value", "google.protobuf.UInt32Value", "google.protobuf.BoolValue", "google.protobuf.StringValue":
+		fd := msgDescriptor.Fields()
+		v := value.Message().Get(fd.ByName(protoreflect.Name("value"))).Message()
+		return fmt.Sprintf("%v", v.Interface()), nil
+	case "google.protobuf.FieldMask":
+		m, ok := value.Interface().(*field_mask.FieldMask)
+		if !ok {
+			return "", nil
+		}
+		return strings.Join(m.Paths, ","), nil
+	default:
+		return "", fmt.Errorf("unsupported message type: %q", string(msgDescriptor.FullName()))
+	}
+}