我很难从WCF数据服务迁移到Web API odata v4。我被困在以下问题上:

odata Web api似乎不支持@ odata.bind。

我找到以下链接:
https://github.com/OData/WebApi/issues/158
有人建议实现一个自己的ODataEntityDeserializer派生类,如下所示:

public class ExtendedODataEntityDeserializer : ODataEntityDeserializer
{
    public ExtendedODataEntityDeserializer(ODataDeserializerProvider deserializerProvider) : base(deserializerProvider)
    {
    }

    public override void ApplyNavigationProperty(
        object entityResource,
        ODataNavigationLinkWithItems navigationLinkWrapper,
        IEdmEntityTypeReference entityType,
        ODataDeserializerContext readContext)
    {
        base.ApplyNavigationProperty(entityResource, navigationLinkWrapper, entityType, readContext);

        foreach (var childItem in navigationLinkWrapper.NestedItems)
        {
            var entityReferenceLink = childItem as ODataEntityReferenceLinkBase;

            if (entityReferenceLink != null)
            {
                var navigationPropertyName = navigationLinkWrapper.NavigationLink.Name;
                Uri referencedEntityUrl = entityReferenceLink.EntityReferenceLink.Url;

                if (!referencedEntityUrl.IsAbsoluteUri)
                {
                    referencedEntityUrl = new Uri(readContext.Request.RequestUri, referencedEntityUrl);
                }

                var linkedEntities = (Model.LinkedEntityCollection)entityResource;
                linkedEntities.Add(navigationPropertyName, referencedEntityUrl);
            }
        }
    }
}

LinkedEntityCollection是我的实体类的基类,它充当字典(MyEntity : LinkedEntityCollection实现很简单)。
public class ExtendedODataDeserializerProvider : ODataDeserializerProvider
{
    private static ExtendedODataDeserializerProvider _instance = null;

    private ExtendedODataDeserializerProvider()
    {
        _instance = this;
    }

    public static ExtendedODataDeserializerProvider Instance
    {
        get { return _instance ?? new ExtendedODataDeserializerProvider(); }
    }

    public override ODataEdmTypeDeserializer GetEdmTypeDeserializer(Microsoft.OData.Edm.IEdmTypeReference edmType)
    {
        return DefaultODataDeserializerProvider.Instance.GetEdmTypeDeserializer(edmType);
    }

    public override ODataDeserializer GetODataDeserializer(Microsoft.OData.Edm.IEdmModel model, Type type, System.Net.Http.HttpRequestMessage request)
    {
        return new ExtendedODataEntityDeserializer(DefaultODataDeserializerProvider.Instance);
    }
}

在http配置中注册:
public static void Register(HttpConfiguration config)
{
    ODataModelBuilder builder = new ODataConventionModelBuilder();

    // registering entities: builder.EntitySet<T>("EntityName") ...

    ODataBatchHandler batchHandler = new DefaultODataBatchHandler(new HttpServer(config));
    batchHandler.MessageQuotas.MaxOperationsPerChangeset = 10;
    batchHandler.MessageQuotas.MaxPartsPerBatch = 10;

    var odataFormatters = ODataMediaTypeFormatters.Create(DefaultODataSerializerProvider.Instance, ExtendedODataDeserializerProvider.Instance);

    config.Formatters.Clear();
    config.Formatters.AddRange(odataFormatters);

    config.MapODataServiceRoute(routeName: "Central", routePrefix: "Odata", model: builder.GetEdmModel(), batchHandler: batchHandler);
}

但是,如果您确实使用此技巧,则会失去在实体之间创建链接的功能,如此aritcle中所述:http://www.asp.net/web-api/overview/odata-support-in-aspnet-web-api/odata-v4/entity-relations-in-odata-v4

不会解析“@ odata.id”,假定它是函数ODataEntityDeserializer.Read中的实体。也许我根本就缺少这里的东西,因为我对Web api相当陌生(config.Formatters.Clear()似乎有点苛刻)。还是有其他解决方法来支持@ odata.bind?

是否有可能在不久的将来实现此功能?

更新

我让我的黑客工作了。问题是我应该从ExtendedODataDeserializerProvider而不是DefaultODataDeserializerProvider导出ODataDeserializerProvider并相应地返回反序列化器:
public override ODataDeserializer GetODataDeserializer(
     Microsoft.OData.Edm.IEdmModel model,
     Type type,
     System.Net.Http.HttpRequestMessage request)
{
    if (type == typeof(ODataActionParameters) ||
        type == typeof(ODataUntypedActionParameters) ||
        type == typeof(Uri))
    {
        return base.GetODataDeserializer(model, type, request);
    }

    return new ExtendedODataEntityDeserializer(DefaultODataDeserializerProvider.Instance);
 }

所以剩下的问题是:何时在ASP.NET WebAPI ODATA中获得@ odata.bind支持?

最佳答案

试图回答



vnext存储库中似乎与此有关。但是,该问题被标记为影响很小。
https://github.com/OData/WebApi/milestones/vNext,因此无法知道何时实现此功能。

关于c# - 在ASP.NET Web API中支持@ odata.bind(发布期间链接到现有实体),我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/30871984/

10-12 12:41
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