JsonStringToMessage fail if there is "bytes" member in proto file

[s894330]

What version of protobuf and what language are you using?
Version: v3.6.1
Language: C++

What operating system (Linux, Windows, ...) and version?
Ubuntu 1404.5
What runtime / compiler are you using (e.g., python version or gcc version)
g++ 4.8.4
What did you do?
Steps to reproduce the behavior:

1. Create simple test.proto like bellow

syntax = "proto2";
package tutorial;
message MyMessage {
  optional bytes msg_id = 1;  //this will cause JsonStringToMessage fail 
//  optional uint32 msg_id = 1;
}

2. Create simple test.cc like bellow

#include <iostream>
#include <string>
#include "google/protobuf/util/json_util.h"
#include "test.pb.h"

using google::protobuf::util::JsonStringToMessage;
using namespace std;

int main(int argc, char* argv[]) {
  GOOGLE_PROTOBUF_VERIFY_VERSION;

  const string test_msg = "{\"msg_id\":\"1\"}";
  tutorial::MyMessage message;

  if (JsonStringToMessage(test_msg, &message).ok()) {
      cout << "parse ok, id: " << message.msg_id() <<  endl;
  } else {
      cout << "Failed to parse msg from json" << endl;
  }
  google::protobuf::ShutdownProtobufLibrary();

  return 0;
}

3. compile and execute it
4. See error "Failed to parse msg from json"

What did you expect to see
If everything OK, we will see "parse ok, id: 1"
What did you see instead?
I see error "Failed to parse msg from json"

error_example.zip

[s894330]

If I change the proto member "msg_id" 's type from bytes to uint32, it will execute success。
So please help to double check to see if this is bug or not

thank you very much :-)

[s894330]

I use MessageToJsonString first to see what is the real output when set msg_id to "1"
And I see it is encoded to "MQ=="
And also, this string "MQ==" can be passed by JsonStringToMessage()

#include <iostream>
#include <string>
#include "google/protobuf/util/json_util.h"
#include "test.pb.h"

using google::protobuf::util::MessageToJsonString;
using google::protobuf::util::JsonStringToMessage;
using google::protobuf::util::JsonPrintOptions;
using namespace std;

int main(int argc, char* argv[]) {
  GOOGLE_PROTOBUF_VERIFY_VERSION;

  tutorial::MyMessage message, message2;
  message.set_msg_id("1");
  string msg;
  string json = "{\"msg_id\":\"MQ==\"}";
  JsonPrintOptions options;
  options.preserve_proto_field_names = true;
  if (MessageToJsonString(message, &msg, options).ok()) {
      cout << "Json msg: " << msg << endl;
  } else {
      cout << "failed to message to jsonstring" << endl;
  }


  cout << "json string: " << json << endl;
  if (JsonStringToMessage(json, &message2).ok()) {
	cout << "id: " << message2.msg_id() << endl;
  } else {
	cout << "failled to jsonstring to message" << endl;
  }

  google::protobuf::ShutdownProtobufLibrary();

  return 0;
}

I think this is a special mechanism in the protobuf when convert string to bytes

If I want to implement this special mechanism by my self without using protobuf. i.e. I can generate acceptable Json message byte string (from byte[]) which can let JsonStringToMessage() pass.
How can I do that in C#?

thank you :-)

[s894330]

After further study, I realize the encode which protobuf used for bytes is base64
And I can use " System.Convert.ToBase64String()" in C# to convert string for JsonStringToMessage()'s input

I think this is not bug, so I will go to close this issue, thank you

[joye92]

If string directly converts to proto bytes , could the result be error?