deserializeMsgPack method throws exception while using with ASP.NET Core

[anuraj]

I am using msgpack.js with Message Pack implementation in C# for ASP.NET Core. But I am getting an error like this.

Here is the code.

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc().AddMvcOptions(option =>
    {
        option.OutputFormatters.Clear();
        option.OutputFormatters.Add(new MessagePackOutputFormatter(StandardResolver.Instance));
        option.InputFormatters.Clear();
        option.InputFormatters.Add(new MessagePackInputFormatter(StandardResolver.Instance));
    }).SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
}

And here is the client code.

<script src="jquery-3.3.1.min.js"></script>
<script src="msgpack.js"></script>
<script>
    $(function () {
        $.get("/api/person", function (data) {
            console.log(deserializeMsgPack(data));
        });
    });
</script>

I am using it in a Web API project, and returning default values controller.

[ygoe]

Can you please also log the content of data and its type (typeof(data))? This doesn't look like a byte array which it's supposed to be.

[anuraj]

It is a complex object. But I tried with simple string, that also not working.

[HttpGet("{id}")]
public ActionResult<string> Get(int id)
{
    return "value";
}

Here is the response header.

[ygoe]

The thing is, the deserializeMsgPack function expects a byte array to be passed in. A byte array consists only of bytes. A byte is an integer value in the range of 0 to 255. All of these values are handled in the code. If something else occurs, then it's not a byte array. And chances are that it needs further conversion to be deserialisable.

I'll have to create a sample project and try out myself what's happening there. I can't make any more assumptions without investigating live code.

Here's code from where I use this library. It processes data received from a WebSocket client.

function onMessage(event) {
    let array = new Uint8Array(event.data);
    let obj = deserialize(array);
}

event.data is already a binary array and is then converted into a Uint8Array. Maybe you need to do something similar.

[anuraj]

Okay. Let me try.

[ygoe]

Any news here? I can't create a demo project because the type MessagePackOutputFormatter cannot be found anywhere. Can you maybe provide a minimal test case for this? I only know about ASP.NET Core 2.1, you seem to use 2.2. Maybe I'll have to wait a bit to run your example.

[anuraj]

Oops, my bad. I am able to resolve it. Full details here - https://dotnetthoughts.net/using-message-pack-with-asp-net-core/. Thank you for your response 👍