OData with multiple keys

I am using the Microsoft.OData 6.11.0 package and I would like API users to be able to use one of three properties (DB primary key, username, or external ID) as a key for the data type representing people. The formats for properties vary so much that they can be easily distinguished. I have set up OData model like this:

ODataModelBuilder builder = new ODataConventionModelBuilder();
builder.EntitySet<Person>("Person");
config.MapODataServiceRoute(
    routeName: "ODataRoute",
    routePrefix: "OData",
    model: builder.GetEdmModel());

      

        
        
        
      

    

In the controller I have:

[EnableQuery]
public SingleResult<Person> Get([FromODataUri] String key) {/*...*/}

[EnableQuery(PageSize = 100)]
public IQueryable<Widget> WidgetsFromPerson([FromODataUri] String key) {/*...*/}

      

        
        
        
      

    

which takes a guess where the id is given and returns the data accordingly. These works:

GET http://localhost/app/OData/Person(1234)
GET http://localhost/app/OData/Person(999999999)
GET http://localhost/app/OData/Person(1234)/Widgets
GET http://localhost/app/OData/Person(999999999)/Widgets

      

        
        
        
      

    

They get me a 404.

GET http://localhost/app/OData/Person('username')
GET http://localhost/app/OData/Person('username')/Widgets

      

        
        
        
      

    

If I cannot do this, is there an alternative syntax I can use to get the username by username, and also widgets for that person by username?

Metadata returned through the API includes the following:

<edmx:Edmx Version="4.0" xmlns:edmx="http://docs.oasis-open.org/odata/ns/edmx">
  <edmx:DataServices>
    <Schema Namespace="MyModel" xmlns="http://docs.oasis-open.org/odata/ns/edm">
      <EntityType Name="AbstractPerson" Abstract="true">
        <Key>
          <PropertyRef Name="PersonId" />
        </Key>
        <Property Name="PersonId" Type="Edm.Int32" Nullable="false" />
      </EntityType>
      <EntityType Name="Person" BaseType="MyModel.Person">
        <Property Name="UserName" Type="Edm.String" />
        <NavigationProperty Name="Widgets" Type="Collection(MyModel.Widget)" />
      </EntityType>
    </Schema>
  </edmx:DataServices>
</edmx:Edmx>

      

        
        
        
      

    

Thank!