如何正确确定变量 google.protobuf.Any 的类型？

huangapple
go评论117阅读模式
英文:

How to correctly determine the type of variable google.protobuf.Any?

问题

请告诉我这段代码中有什么问题，为什么变量的类型无法确定，传递的url类型是google.protobuf.Any？

  1. package main
  3. import (
  4. 	"fmt"
  6. 	"google.golang.org/protobuf/reflect/protoreflect"
  7. 	"google.golang.org/protobuf/reflect/protoregistry"
  8. )
  10. func main() {
  11. 	var res protoregistry.MessageTypeResolver = protoregistry.GlobalTypes
  12. 	typeUrl := "type.googleapis.com/google.protobuf.StringValue"
  13. 	fmt.Println(protoreflect.FullName(typeUrl))
  14. 	msgType, err := protoregistry.GlobalTypes.FindMessageByName(protoreflect.FullName("google.protobuf.StringValue"))
  15. 	if err != nil {
  16. 		fmt.Println(err)
  17. 	}
  18. 	fmt.Println(msgType)
  20. 	msgType, err = res.FindMessageByURL(typeUrl)
  21. 	if err != nil {
  22. 		fmt.Println(err)
  23. 	}
  24. 	fmt.Println(msgType)
  25. }

proto: not found

proto: not found

英文:

Please tell me what is wrong in this code, why the type is not determined for the variable, for the transmitted url type google.protobuf.Any?

  1. package main
  3. import (
  4. 	"fmt"
  6. 	"google.golang.org/protobuf/reflect/protoreflect"
  7. 	"google.golang.org/protobuf/reflect/protoregistry"
  8. )
  10. func main() {
  11. 	var res protoregistry.MessageTypeResolver = protoregistry.GlobalTypes
  12. 	typeUrl := "type.googleapis.com/google.protobuf.StringValue"
  13. 	fmt.Println(protoreflect.FullName(typeUrl))
  14. 	msgType, err := protoregistry.GlobalTypes.FindMessageByName(protoreflect.FullName("google.protobuf.StringValue"))
  15. 	if err != nil {
  16. 		fmt.Println(err)
  17. 	}
  18. 	fmt.Println(msgType)
  20. 	msgType, err = res.FindMessageByURL(typeUrl)
  21. 	if err != nil {
  22. 		fmt.Println(err)
  23. 	}
  24. 	fmt.Println(msgType)
  25. }

proto: not found
<nil>
proto: not found
<nil>

答案1

得分: 1

错误是protoregistry.NotFound，因为在protoregistry.GlobalTypes中没有注册消息类型。

要注册google.protobuf.Any，您应该导入包google.golang.org/protobuf/types/known/anypb。并且google.protobuf.Any是由该包的init函数注册的（请参阅源代码）。

要注册google.protobuf.StringValue，您应该导入包google.golang.org/protobuf/types/known/wrapperspb。

这是更新后的演示代码，用于查找google.protobuf.StringValue的消息字节：

  1. package main
  3. import (
  4. 	"fmt"
  6. 	"google.golang.org/protobuf/reflect/protoregistry"
  7.     // 仅导入该包以产生副作用（初始化）。
  8.     // 请参阅https://go.dev/ref/spec#Import_declarations。
  9. 	_ "google.golang.org/protobuf/types/known/anypb"
  10. 	_ "google.golang.org/protobuf/types/known/wrapperspb"
  11. )
  13. func main() {
  14. 	res := protoregistry.GlobalTypes
  15. 	fmt.Println("NumMessages:", res.NumMessages())
  17. 	msgType, err := protoregistry.GlobalTypes.FindMessageByName("google.protobuf.StringValue")
  18. 	if err != nil {
  19. 		fmt.Println(err)
  20. 	}
  21. 	fmt.Println(msgType)
  23. 	msgType, err = res.FindMessageByURL("type.googleapis.com/google.protobuf.StringValue")
  24. 	if err != nil {
  25. 		fmt.Println(err)
  26. 	}
  27. 	fmt.Println(msgType)
  28. }
英文:

The error is protoregistry.NotFound because there are not message types got registered in protoregistry.GlobalTypes.

To register google.protobuf.Any, you should import the package google.golang.org/protobuf/types/known/anypb. And google.protobuf.Any is registered by the init function of that package (see the source code).

To register google.protobuf.StringValue, you should import the package google.golang.org/protobuf/types/known/wrapperspb.

Here is the updated demo that finds the message byte of google.protobuf.StringValue:

  1. package main
  3. import (
  4. 	&quot;fmt&quot;
  6. 	&quot;google.golang.org/protobuf/reflect/protoregistry&quot;
  7.     // importing the package solely for its side-effects (initialization).
  8.     // See https://go.dev/ref/spec#Import_declarations.
  9. 	_ &quot;google.golang.org/protobuf/types/known/anypb&quot;
  10. 	_ &quot;google.golang.org/protobuf/types/known/wrapperspb&quot;
  11. )
  13. func main() {
  14. 	res := protoregistry.GlobalTypes
  15. 	fmt.Println(&quot;NumMessages:&quot;, res.NumMessages())
  17. 	msgType, err := protoregistry.GlobalTypes.FindMessageByName(&quot;google.protobuf.StringValue&quot;)
  18. 	if err != nil {
  19. 		fmt.Println(err)
  20. 	}
  21. 	fmt.Println(msgType)
  23. 	msgType, err = res.FindMessageByURL(&quot;type.googleapis.com/google.protobuf.StringValue&quot;)
  24. 	if err != nil {
  25. 		fmt.Println(err)
  26. 	}
  27. 	fmt.Println(msgType)
  28. }

huangapple
  • 本文由 发表于 2023年3月24日 01:18:16
  • 转载请务必保留本文链接：https://go.coder-hub.com/75826138.html
  • go
  • protobuf-go
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