How to pass Array to OData function in ASP.NET Web API implementation?

Question

The specification of OData V4 states that it MUST be possible: https://issues.oasis-open.org/browse/ODATA-636.

"Complex types and arrays can only be passed to functions through parameter aliases"

When I'm trying to pass an array with OData parameter aliases an exception occurs.

/TestEntities/NS.TestFunction(ArrayHere=@p)?@p=[1,2,3]

Results in:

Unable to cast object of type 'EdmValidCoreModelPrimitiveType' to type 'Microsoft.OData.Edm.IEdmStructuredType

The interesting thing is that the metadata document is correctly composed for such cases:

<Function Name="TestFunction" IsBound="true">
  <Parameter Name="bindingParameter" Type="Collection(NS.TestEntity)"/>
  <Parameter Name="ArrayHere" Type="System.Int32[]"/>
  <ReturnType Type="Collection(NS.TestEntity)"/>
</Function>

Is it possible with ASP.NET MVC Web API 2 OData to pass an array to OData function in query string?

UPDATE:

Here is the code to build the EDM model and the controller.

 var builder = new ODataConventionModelBuilder();

 builder.Namespace = "NS";

 builder.EntitySet<TestEntity>("TestEntities");

 builder.EntityType<TestEntity>().Collection
    .Function("TestFunction")
    .ReturnsCollectionFromEntitySet<TestEntity>("TestEntities")
    .Parameter<int[]>("ArrayHere");

Controller:

public class TestEntitiesController : ODataController
{
    public IEnumerable<TestEntity> TestFunction(int[] arrayHere)
    {
        throw new NotImplementedException();
    }
}

Marking parameter with [FromODataUri] does not solve the problem.

UPDATE 2:

Here is the stack trace:

at Microsoft.OData.Core.UriParser.TypePromotionUtils.CanConvertTo(SingleValueNode sourceNodeOrNull, IEdmTypeReference sourceReference, IEdmTypeReference targetReference)
at Microsoft.OData.Core.UriParser.Parsers.MetadataBindingUtils.ConvertToTypeIfNeeded(SingleValueNode source, IEdmTypeReference targetTypeReference)
at Microsoft.OData.Core.UriParser.Parsers.FunctionCallBinder.BindSegmentParameters(ODataUriParserConfiguration configuration, IEdmOperation functionOrOpertion, ICollection`1 segmentParameterTokens)
at Microsoft.OData.Core.UriParser.Parsers.ODataPathParser.TryBindingParametersAndMatchingOperation(String identifier, String parenthesisExpression, IEdmType bindingType, ODataUriParserConfiguration configuration, ICollection`1& boundParameters, IEdmOperation& matchingOperation)
at Microsoft.OData.Core.UriParser.Parsers.ODataPathParser.TryCreateSegmentForOperation(ODataPathSegment previousSegment, String identifier, String parenthesisExpression)
at Microsoft.OData.Core.UriParser.Parsers.ODataPathParser.CreateNextSegment(String text)
at Microsoft.OData.Core.UriParser.Parsers.ODataPathParser.ParsePath(ICollection`1 segments)
at Microsoft.OData.Core.UriParser.Parsers.ODataPathFactory.BindPath(ICollection`1 segments, ODataUriParserConfiguration configuration)
at Microsoft.OData.Core.UriParser.ODataUriParser.ParsePathImplementation()
at Microsoft.OData.Core.UriParser.ODataUriParser.Initialize()
at System.Web.OData.Routing.DefaultODataPathHandler.Parse(IEdmModel model, String serviceRoot, String odataPath, Boolean enableUriTemplateParsing)
at System.Web.OData.Routing.DefaultODataPathHandler.Parse(IEdmModel model, String serviceRoot, String odataPath)
at System.Web.OData.Routing.ODataPathRouteConstraint.Match(HttpRequestMessage request, IHttpRoute route, String parameterName, IDictionary`2 values, HttpRouteDirection routeDirection)
at System.Web.Http.Routing.HttpRoute.ProcessConstraint(HttpRequestMessage request, Object constraint, String parameterName, HttpRouteValueDictionary values, HttpRouteDirection routeDirection)
at System.Web.Http.Routing.HttpRoute.ProcessConstraints(HttpRequestMessage request, HttpRouteValueDictionary values, HttpRouteDirection routeDirection)
at System.Web.Http.Routing.HttpRoute.GetRouteData(String virtualPathRoot, HttpRequestMessage request)
at System.Web.Http.WebHost.Routing.HttpWebRoute.GetRouteData(HttpContextBase httpContext)

Answer 1

Assuming you're using OData V4 you need to use CollectionParameter when registering the function and you're missing the [FromODataUri] on the arrayHere parameter. Also, try it with IEnumerable<int> instead of an array.

var builder = new ODataConventionModelBuilder();

 builder.Namespace = "NS";

 builder.EntitySet<TestEntity>("TestEntities");

 builder.EntityType<TestEntity>().Collection
    .Function("TestFunction")
    .ReturnsCollectionFromEntitySet<TestEntity>("TestEntities")
    .CollectionParameter<int>("ArrayHere");

With the function in the controller like this...

[HttpGet]
public async Task<IHttpActionResult> TestFunction([FromODataUri] IEnumerable<int> ArrayHere)
{
    // Do stuff
}

Now you can make a request such as...

http://yourRestService/API/TestEntities/NS.TestFunction(ArrayHere=[1,2,3])

As a note, you can also accept an array of complex types as well. You'll have to url encode the json for the array and use a parameter alias so you'll end up with something like this...

 builder.EntityType<TestEntity>().Collection
    .Function("TestFunction2")
    .ReturnsCollectionFromEntitySet<TestEntity>("TestEntities")
    .CollectionParameter<person>("ArrayHere");

and

[HttpGet]
public async Task<IHttpActionResult> TestFunction2([FromODataUri] IEnumerable<person> ArrayHere)
{
    // Do stuff
}

http://yourRestService/API/TestEntities/NS.TestFunction2(ArrayHere=@ArrayData)?@ArrayData=%5B%7B%22FirstName%22%3A%22Bob%22%2C+%22LastName%22%3A%22Dole%22%7D%2C%7B%22FirstName%22%3A%22Bill%22%2C+%22LastName%22%3A%22Clinton%22%7D%5D

Answer 2

I don't know which version of OData you're currently using, but here's a solution I've implemented which works for v4 and passing in simple arrays to an OData Action Method

In your WebConfig.cs

ODataModelBuilder builder = new ODataConventionModelBuilder();
builder.EntitySet<TestEntity>("TestEntities");

builder.Namespace = "NS";

builder.EntityType<TestEntity>()
        .Action("TestAction")
    .CollectionParameter<string>("ArrayHere");    

And your controller method here

[HttpPost]
public async Task<IHttpActionResult> TestAction([FromODataUri] int key, ODataActionParameters parameters)
{
    // Do your thing here..
    var invites = parameters["ArrayHere"] as IEnumerable<string>;
}

The resulting API endpoint request should look something like the following:

POST http://localhost/odata/TestEntities(1)/NS.TestAction HTTP/1.1
Content-type: application/json
Host: localhost:49255
Content-Length: 37

{"ArrayHere":["hello", "world"]}    

I went down this particular problem a few times and couldn't make it work for an OData function. I dug a little bit deeper and found the CollectionParameter<>() method which sorted everything out. I didn't go back and try it with a Function as I didn't really see the need. I hope this helps you out