WebApi OData实体集/密钥/导航/密钥支持

Question

我正在研究在WebApi中使用odata.到目前为止这么好,我喜欢它比wcf数据服务更灵活.

但是当我尝试在模型中使用虚拟IQueryable属性时遇到问题.

所以例如我有这些模型类:

public class MainItem
{
    public int Id { get; set;}
    public virtual IEnumerable<SubItem> SubItems { get; set;}
}

而我的MainItemsController看起来像这样

public class MainItemsController : EntitySetController<MainItem, int>
{
    [Queryable]
    public override IQueryable<MainItem> Get()
    {
        return SomeMainItemIQueryable();
    }

    public override GetEntityByKey(int key) 
    {
        return SingleMainItem(key);
    }

    [Queryable]
    public IQueryable GetSubItems(int key)
    {
        return SomeSubItemIQueryable(SingleMainItem(key));
    }
}

我在以下网址上得到了正确的结果:/ odata/MainItems/odata/MainItems(1)/ odata/MainItems(1)/ SubItems

但当我尝试做/ odata/MainItems(1)/ SubItems(1)

我收到此错误此服务不支持"〜/ entityset/key/navigation/key"形式的OData请求

我很乐意将此调用以及/ odata/MainItems(1)/ SubItems重定向到SubItemsController.

我可以通过制作一个自定义的ODataPathHandler来做到这一点,但这不是正确的做法.

Answer 1

那就对了.您不需要自定义路径处理程序.它代表了我们理解的有效OData URL,并且可以将其解析为ODataPath.您需要的是自定义路由约定.路由约定将ODataPath映射到控制器和操作.默认情况下,我们仅提供处理WCF DS客户端生成的URL的基本路由约定.看起来您正在使用我们没有路由约定的URL.写一个很简单.例,

public class ContainmentRoutingConvention : IODataRoutingConvention
{
    public string SelectAction(ODataPath odataPath, HttpControllerContext controllerContext, ILookup<string, HttpActionDescriptor> actionMap)
    {
        IEdmEntitySet entitySet = odataPath.EntitySet;

        if (odataPath.PathTemplate == "~/entityset/key/navigation")
        {
            controllerContext.RouteData.Values["key"] = (odataPath.Segments[1] as KeyValuePathSegment).Value;
            return "Get" + entitySet.Name;
        }
        else if (odataPath.PathTemplate == "~/entityset/key/navigation/key")
        {
            controllerContext.RouteData.Values["key1"] = (odataPath.Segments[1] as KeyValuePathSegment).Value;
            controllerContext.RouteData.Values["key2"] = (odataPath.Segments[3] as KeyValuePathSegment).Value;
            return "Get" + entitySet.ElementType.Name;
        }

        return null;
    }

    public string SelectController(ODataPath odataPath, HttpRequestMessage request)
    {
        if (odataPath.PathTemplate == "~/entityset/key/navigation" ||
            odataPath.PathTemplate == "~/entityset/key/navigation/key")
        {
            IEdmNavigationProperty navigationProperty = (odataPath.Segments[2] as NavigationPathSegment).NavigationProperty;
            IEdmEntitySet entitySet = odataPath.EntitySet; // the target entity set, which would be 'SubItems';

            return entitySet.Name;
        }

        return null;
    }
}

这只会处理你提到的两个网址.应该很容易扩展以支持其他网址.

处理〜/ entityset/key/navigation的动作的签名将是IEnumerable<Order> GetOrders(int key)和url~/entityset/key/navigation/key一样,它将是Order GetOrder(int key1, int key2).