如何从 RequestFilter 中访问 ServiceStack 的 Service.Db 实例？

Question

我有一个 C# ServiceStack RequestFilter...

public class VerifyRequestedSystemsAttribute : Attribute, IHasRequestFilter
{
    IHasRequestFilter IHasRequestFilter.Copy()
    {
        return this;
    }


    public void RequestFilter(IRequest req, IResponse res, object requestDto)
    {
        var systemIds = RetrieveSystemIds(requestDto);

        Db.Select...? //How do I make Db available for use?
    }

    private List<int> RetrieveSystemIds(object requestDto)
    {
        // Find the properties on the requestDto having the RequestedSystemIds attribute
        var type = requestDto.GetType();
        var properties = type.GetPublicProperties();
        foreach (var systemIds in
                    from p in properties
                    where p.HasAttribute<RequestedSystemsAttribute>() && p.PropertyType == typeof(List<int>) && p.CanRead && p.CanWrite
                    select p.GetValue(requestDto, null)
                        as List<int>)
            return systemIds;

        return new List<int>();
    }


    // The lowest priority means it will run first, before other custom attributes
    public int Priority { get { return 0; } }
}

你能看到吗 - 在 RequestFilter 方法中我想查询数据库，但我无权访问 Service.Db 实例。

获取 Service.Db 实例的正确方法是什么？我应该改用 ServiceRunner 吗？

Answer 1

IOC 依赖项也被注入到过滤器属性中，因此您可以添加请求过滤器属性所需的依赖项的公共属性，例如：

public class VerifyRequestedSystemsAttribute : Attribute, IHasRequestFilter
{
    public IDbConnectionFactory DbFactory { get; set; }

    private List<int> RetrieveSystemIds(object requestDto)
    {
        using (var db = DbFactory.OpenConnection())
        {
            //...
        }
    }
}