In EntityFrameworkDocumentMaterializer<T> and in EntityFrameworkToManyRelatedResourceDocumentMaterializer<TPrimaryResource, TRelated> there are methods like this.

        private IQueryable<TResource> Filter<TResource>(Expression<Func<TResource, bool>> predicate,
            params Expression<Func<TResource, object>>[] includes) where TResource : class
        {
            IQueryable<TResource> query = DbContext.Set<TResource>();
            if (includes != null && includes.Any())
                query = includes.Aggregate(query, (current, include) => current.Include(include));

            if (predicate != null)
                query = query.Where(predicate);

            return query.AsQueryable();
        }

It seems to me there is an implication on includes but I don't unterstand exactly what should happend and where the includes should be filled in. At the moment query = includes.Aggregate(query, (current, include) => current.Include(include)); is never hit because includes are never filled.

Thanks for some suggestions.

@spike83 You're right - somehow that capability got lost at some point. Both related resource materializer classes should add something like the following:

protected virtual Expression<Func<TResource, object>>[] GetIncludes()
{
    return new Expression<Func<TResource, object>>[] {};
}

to allow overriding classes to specify navigation properties to include.

@csantero ok if I got it right the GetIncludes method you suggested is not directly related to the includes in the resulting document. It's for eager loading...? since queryable.Include() adds joins to resulting linq to entities sql statement.
So I added the method you suggested and also added a default implementation wich eager loads relations specified by the URL parameter &include=.

I think it's almost done.

@spike83 let me know when you're done and I'll take a closer look for review.

For my needs it works like a charm. So I'm done. Please have a strict look what is missing and can be improved before merge. I also enabled the epic github new feature Allow edits from maintainers ;-)
Thanks.

@spike83, thanks, this is great!