Dictionary in protocol buffers

Is there any way to serialize a diction开发者_JAVA技巧ary using protocol buffers, or I'll have to use Thrift if I need that?

For future answer seekers, ProtoBuf now supports Maps natively:

message MapMessage
{
    map<string, string> MyMap = 1;
}

Protobuf specification now supports dictionaries (maps) natively.

Original answer

People typically write down the dictionary as a list of key-value pairs, and then rebuild the dictionary on the other end.

message Pair {
   string key = 1;
   string value = 2;
}

message Dictionary {
   repeated Pair pairs = 1;
}

You can check the ProtoText package.

Assume you want to serialize a dict person_dict to a pre-defined PersonBuf protobuf object defined in personbuf_pb2 module.

In this case, to use ProtoText,

import ProtoText
from personbuf_pb2 import PersonBuf

obj = PersonBuf()
obj.update(person_dict)

I firstly comment the @Flassari 's answer as it is really convenient.

However, in my case, I needed map<Type, repeated AnyModel> where :

enum Type {
    Undefined = 0;
    Square = 1;
    Circle = 2;
}

message AnyModel {
    string Name = 1;
}

Here I just want to return a dictionary that, for each type, contain a list of AnyModel

However, I didn't find a better workaround than the one proposed by @JesperE so I did the following: (as you can't use enum as key in map)

message MyRPCBodyCall {
    map<string, AnyModels> Models = 1;
}

enum Type {
    Undefined = 0;
    Square = 1;
    Circle = 2;
}

message AnyModel {
    string Name = 1;
}

message AnyModelArray {
    repeated AnyModel AnyModels = 1;
}

Here I convert from/to string my enum using my chosen code languages from both server/client side

So both approaches are actually valid answers IMO, depends on your requirements.