Using System.Text.Json deserialization issues

[talfirevic]

I've set up System.Text.Json as a default serialized by implementing ISerializer and I'm having issues with a basic use case - store and retrieve an entity.

this is the relevant part of the CustomSerializer

 public string ToJson(object? document)
    {
        return JsonSerializer.Serialize(document);
    }

    public T FromJson<T>(Stream stream)
    {
        return JsonSerializer.Deserialize<T>(stream);
    }

Storing an object invokes ToJson, and it works as intended.

Querying that same entity gets the item from the database, but when FromJson<T> is invoked, deserialization breaks because the string starts with 0x01 for some odd reason.

I'm missing something very obvious, aren't I?

P.S. when the object is being stored, the serializer does not produce a JSON string with 0x01 at the beginning, it only happens when I retrieve the object from the database.

[Hawxy]

Is there a reason you're implementing this yourself? There's already built in support for STJ and it handles this particular problem.

[talfirevic]

@Hawxy , I'm aware this is already implemented. I plan on using a different serializer (likely MessagePack) when I get the time to deal with the whole serialization topic in the app.

By "this particular problem" were you referring to the 0x01 thing or STJ serialization in general?

[Hawxy]

I plan on using a different serializer (likely MessagePack)

I'm not sure how that would work. Marten uses jsonb selectors and thus serializing to encoded MessagePack would break a lot of functionality.

By "this particular problem" were you referring to the 0x01 thing or STJ serialization in general?

The 0x01 problem. Marten's STJ serializer has a custom stream implementation that skips the control character:
https://github.com/JasperFx/marten/blob/64598221e07050a8d1d82ef855011994e094260a/src/Marten/Services/SystemTextJsonSerializer.cs

[jeremydmiller]

@talfirevic MessagePack would never work for the document storage. That would completely break the Linq support.

[jeremydmiller]

I'm switching this to a discussion as there's not anything to "fix" in Marten itself.

@talfirevic My advice is to just use the built in STJ serialization strategy here that was built to be able to support Linq querying.