integrate request builder into HTTP client for googleapis support (#159)

builder/helpers.go

@@ -0,0 +1,114 @@
+package builder
+
+import (
+	"encoding/base64"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"google.golang.org/protobuf/reflect/protoreflect"
+)
+
+// findFieldByPath resolves a dot-separated field path in a protobuf message and returns the protoreflect value and its descriptor.
+func findFieldByPath(msg protoreflect.Message, fieldPath string) (protoreflect.Value, protoreflect.FieldDescriptor, bool) {
+	var (
+		current    = msg
+		parts      = strings.Split(fieldPath, ".")
+		partsCount = len(parts) - 1
+	)
+
+	for i, part := range parts {
+		fd, ok := findFieldByName(current, part)
+		if !ok {
+			return protoreflect.Value{}, nil, false
+		}
+
+		val := current.Get(fd)
+		if i == partsCount { // it's last part
+			return val, fd, true
+		}
+
+		if fd.Kind() != protoreflect.MessageKind {
+			return protoreflect.Value{}, nil, false
+		}
+		current = val.Message()
+	}
+
+	return protoreflect.Value{}, nil, false
+}
+
+// findFieldByName find a field name in a protobuf message and returns the protoreflect field descriptor.
+func findFieldByName(msg protoreflect.Message, fieldName string) (protoreflect.FieldDescriptor, bool) {
+	fields := msg.Descriptor().Fields()
+	for i := 0; i < fields.Len(); i++ {
+		fd := fields.Get(i)
+		if fd.JSONName() == fieldName {
+			return fd, true
+		}
+	}
+	return nil, false
+}
+
+// isZeroValue checks if protoreflect.Value is zero for the field.
+func isZeroValue(val protoreflect.Value, fd protoreflect.FieldDescriptor) bool {
+	if fd.IsList() {
+		return val.List().Len() == 0
+	}
+	if fd.IsMap() {
+		return val.Map().Len() == 0
+	}
+
+	switch fd.Kind() {
+	case protoreflect.StringKind:
+		return val.String() == ""
+	case protoreflect.BytesKind:
+		return len(val.Bytes()) == 0
+	case protoreflect.BoolKind:
+		return !val.Bool()
+	case protoreflect.Int32Kind, protoreflect.Sint32Kind, protoreflect.Sfixed32Kind,
+		protoreflect.Int64Kind, protoreflect.Sint64Kind, protoreflect.Sfixed64Kind:
+		return val.Int() == 0
+	case protoreflect.Uint32Kind, protoreflect.Fixed32Kind,
+		protoreflect.Uint64Kind, protoreflect.Fixed64Kind:
+		return val.Uint() == 0
+	case protoreflect.FloatKind, protoreflect.DoubleKind:
+		return val.Float() == 0
+	case protoreflect.EnumKind:
+		return val.Enum() == 0
+	case protoreflect.MessageKind:
+		return !val.Message().IsValid()
+	default:
+		return !val.IsValid()
+	}
+}
+
+// stringifyValue converts protoreflect.Value to string for path/query substitution.
+func stringifyValue(val protoreflect.Value, fd protoreflect.FieldDescriptor) (string, error) {
+	switch fd.Kind() {
+	case protoreflect.StringKind:
+		return val.String(), nil
+	case protoreflect.BytesKind:
+		return base64.StdEncoding.EncodeToString(val.Bytes()), nil
+	case protoreflect.BoolKind:
+		if val.Bool() {
+			return "true", nil
+		}
+		return "false", nil
+	case protoreflect.Int32Kind, protoreflect.Sint32Kind, protoreflect.Sfixed32Kind,
+		protoreflect.Int64Kind, protoreflect.Sint64Kind, protoreflect.Sfixed64Kind:
+		return fmt.Sprintf("%d", val.Int()), nil
+	case protoreflect.Uint32Kind, protoreflect.Fixed32Kind,
+		protoreflect.Uint64Kind, protoreflect.Fixed64Kind:
+		return fmt.Sprintf("%d", val.Uint()), nil
+	case protoreflect.FloatKind, protoreflect.DoubleKind:
+		return strconv.FormatFloat(val.Float(), 'g', -1, 64), nil
+	case protoreflect.EnumKind:
+		ed := fd.Enum().Values().ByNumber(val.Enum())
+		if ed != nil {
+			return string(ed.Name()), nil
+		}
+		return fmt.Sprintf("%d", val.Enum()), nil
+	default:
+		return "", fmt.Errorf("unsupported field kind: %s", fd.Kind())
+	}
+}