how to Deserialize BSON Object

[mirkojpn87]

hi.
i have a couple Bson serialized Databases with C# and MongoDB library.
under C# i'm able to deserialize it like this :

static void Main(string[] args)
    {
        foreach (string file in Directory.EnumerateFiles(Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location), "*.bson"))
        {
            byte[] contents =
                File.ReadAllBytes(file);

            Databases cl = BsonSerializer.Deserialize<Databases>(contents);
            Console.WriteLine(cl._databases["001"]._date.ToString());
        }
    }

    private class Databases
    {
        public Dictionary<string, SampleClass> _databases;
    }

i'm looking to do the same in C++ is possible?

[nlohmann]

Yes, this should be possible. For the conversion of user-defined types (like Databases in your case), see https://json.nlohmann.me/features/arbitrary_types/. Anything related to BSON is documented here: https://json.nlohmann.me/features/binary_formats/bson/

[mirkojpn87]

Hi.
i'm working on it...but i have some troubles to figure out how to make it works.

what i have is this

what i'm missing out?

[gregmarr]

It doesn't look like you've implemented to_json for EventCondition.

[mirkojpn87]

since i'm not going to use everytime the same class ( that in this case is EventCondition) but a lot of other, i have to implement to_json for every class that i'm going to use?

[nlohmann]

Yes

[gregmarr]

Until C++ gets static reflection and code generation in C++23 or later, there is no way for the library to automatically (de-)serialize a class that doesn't have that function.