How best to pass AdditionalParameters in request?

Great library guys.

I didn’t know where else to ask this, hopefully this is semi-appropriate… I’m trying to send column level custom filter data (date ranges, lookups, etc) back to the server.

I see that IDataTablesRequest can take an AdditionalParameters dictionary, but I’m not sure exactly how to structure my object on the client or where to pass it in. ajax.data perhaps? I’d love to see an example.

Thanks in advance for the help

[ronnieoverby]

In my aspnet core project, I just did this:

// some.js
$('#myTable').DataTable({
    serverSide: true,
    ajax: {
        url: '/someAjaxUrl',
        data: function (d) {
            d.appJson = JSON.stringify({
                someNumber: 123,
                someString: "hello",
                someNumbers: [1,2,3]
            });
        }
    },
    // other stuff
});

// Startup.cs
services.RegisterDataTables(ctx =>
{
    var appJson = ctx.ValueProvider.GetValue("appJson").FirstValue ?? "{}";
    return JsonConvert.DeserializeObject<IDictionary<string, object>>(appJson);
}, true);


// DataTablesExts.cs
public static class DataTablesExts
{
    public static T Get<T>(this IDataTablesRequest request, string key)
    {
        var obj = request.AdditionalParameters[key];
        return Convert<T>(obj);
    }

    public static bool TryGet<T>(this IDataTablesRequest request, string key, out T value)
    {
        if (request.AdditionalParameters.TryGetValue(key, out object obj))
        {
            value = Convert<T>(obj);
            return true;                
        }

        value = default(T);
        return false;
    }

    private static readonly JToken JNull = JToken.Parse("null");
    private static T Convert<T>(object obj)
    {
        T AsNull() => JNull.ToObject<T>();

        if (obj == null)
            return AsNull();

        if (obj is T tobj)
            return tobj;

        if (obj is JToken jt)
            return jt.ToObject<T>();

        try
        {
            return JToken.FromObject(obj).ToObject<T>();
        }
        catch (FormatException) when (obj is string s && string.IsNullOrWhiteSpace(s))
        {
            return AsNull();
        }
    }
}


// SomeController.cs or SomePage.cshtml.cs
public async Task<DataTablesJsonResult> OnGetQueryAsync(IDataTablesRequest request)
{
    var someNumber = request.Get<int>("someNumber");
    var someString = request.Get<string>("someString");
    var someNumbers = request.Get<int[]>("someNumbers");
    // do other work here....
}

Not the best thing in the world, but damn, I just wanted to get on with building my app.

[ALMMa]

@danielearrighi Thanks!

That sounds interesting. The only downside I can think of if the multiple .Where, which could be replaced by a single (faster compiling/running) statement.

I’ll sure give that a try. Maybe provide an automatic binder (with some automatic request parameters parsing) and a manual binder (with override capability to solve complex cases, like nested objects).

I just need to test, however, on POST. Dunno for sure right now but in some cases, after parsing body element, you cannot read values again. I have to double check that on all AspNet Core, MVC and WebApi to make sure that parsing parameters automatically won’t break the main request params binding (eg: draw, columns, etc).