{"id":4241,"date":"2020-10-19T21:58:36","date_gmt":"2020-10-20T04:58:36","guid":{"rendered":"https:\/\/devblogs.microsoft.com\/odata\/?p=4241"},"modified":"2021-09-29T13:51:47","modified_gmt":"2021-09-29T20:51:47","slug":"asp-net-odata-8-0-preview-for-net-5","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/odata\/asp-net-odata-8-0-preview-for-net-5\/","title":{"rendered":"ASP.NET Core OData 8.0 Preview for .NET 5"},"content":{"rendered":"

Recently, OData team released the 8.0.0 preview version of ASP.NET Core OData on nuget.org<\/a>. It is the first version of OData supporting .NET 5, especially for ASP.NET Core 5. This version includes some breaking changes, such as model builder separation, namespace changes and configuration changes etc. Most importantly, the routing mechanism is changed a lot comparing to the previous 7.x version.<\/p>\n

This post is intended to introduce such changes using a basic tutorial about how to build OData service through ASP.NET Core OData 8.0 preview package. Besides, we are looking for requirements of features and reports of any bugs, issues that we can fix before the general availability. Please don’t hesitate to file any kind of issues at ASP.NET Core OData Github Repo<\/a>.<\/p>\n

Let us get started.<\/p>\n

OData Service in practical<\/h2>\n

The basic flow to create OData service using ASP.NET Core OData 8.0 preview is same as the flow introduced in ASP.NET Core OData now Available<\/a>. Please refer to that post for other details not listed in this post.<\/p>\n

Create application<\/h3>\n

Visual Studio 2019 preview is necessary to create the ASP.NET Core 5.0 web application. So, let’s select “ASP.NET Core Web Application<\/strong>” project template in the following dialog to create the skeleton of the ASP.NET Core OData service.<\/p>\n

<\/p>\n

In the following “Create a new ASP.NET Core web application<\/strong>” dialog, select “API<\/strong>” and un-check the \u201cConfigure for HTTPs<\/strong>\u201d for simplicity to create the application.\nBe noticed, ASP.NET Core 5.0 is selected as the target platform.<\/p>\n

<\/p>\n

As mentioned, ASP.NET Core OData 8.0 is a Nuget package. Let’s use Nuget Package Manager<\/strong> to install it. In the below dialog, use “nuget.org<\/strong>” as package source, search and select “Microsoft.AspNetCore.OData<\/strong>” package, check “Include prerelease<\/strong>” and select 8.0.0-preview version to install.<\/p>\n

<\/p>\n

EF Core<\/a> is also used in this post, so do the same process as above to install “Microsoft.EntityFrameworkCore.InMemory<\/strong>” (so far, it’s 5.0.0-rc.2) and its dependencies (for simplicity, we use In Memory data source also).<\/p>\n

Build Entity Data Model<\/h3>\n

We re-use the C# class models in Add the Model class section<\/a> of ASP.NET Core OData now Available to build the Entity Data Model (EDM).<\/p>\n

We can copy\/paste the “GetEdmModel()<\/strong>” method at Build the Edm Model<\/a> into “Startup<\/strong>” class in the new project.<\/p>\n

Be noted, the ASP.NET Core OData 8 preview depends on an individual OData model builder nuget package. The individual OData model builder has the same functionality as it in the existing Web API OData except the namespace. Please find more details about the OData model builder from OData Model Builder now Available<\/a>.<\/p>\n

Register the OData Services<\/strong><\/h3>\n

There is a big configuration change comparing to the previous ASP.NET Core OData version. In the previous 7.5 Web API OData version, we have “AddOData()<\/strong>” to register the mandatory services ahead to provide OData functionality and “MapODataRoute(…)<\/strong>” to register the single OData route based on the given OData Edm model. For example:<\/p>\n

public class Startup\r\n{\r\n    public void ConfigureServices(IServiceCollection services)\r\n    {\r\n        services.AddRouting();\r\n        services.AddOData();\r\n    }\r\n\r\n    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)\r\n    {\r\n        app.UseRouting();\r\n        app.UseEndpoints(endpoints =>\r\n        {\r\n            endpoints.MapODataRoute(\"odata\", \"odata\", GetEdmModel());\r\n        });\r\n    }\r\n\r\n    private static IEdmModel GetEdmModel()\r\n    {\r\n        \/\/ \u2026\r\n    }\r\n}\r\n<\/pre>\n
In the 8.0 preview, the configuration is changed. Where, “AddOData()<\/strong>” is kept, meanwhile “MapODataRoute(…)<\/strong>” is gone. “AddOData()<\/strong>” accepts a delegate to do the configuration on ODataOptions<\/strong>. For example, We can register Edm model, setup the query configuration by calling methods on ODataOptions<\/strong>. Below is the new configuration in 8.0 preview: [AddModel<\/strong> is renamed as AddRouteComponents<\/strong> in 8.0.]<\/p>\n
public class Startup\r\n{\r\n    public void ConfigureServices(IServiceCollection services)\r\n    {\r\n        services.AddDbContext<BookStoreContext>(opt => opt.UseInMemoryDatabase(\"BookLists\"));\r\n        services.AddControllers();\r\n        services.AddOData(opt => opt.AddModel(\"odata\", GetEdmModel()));\r\n    }\r\n\r\n    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)\r\n    {\r\n        app.UseRouting();\r\n        app.UseEndpoints(endpoints =>\r\n        {\r\n            endpoints.MapControllers();\r\n        });\r\n    }\r\n\r\n    private static IEdmModel GetEdmModel()\r\n    {\r\n        \/\/ \u2026\r\n    }\r\n}\r\n<\/pre>\n
Run and test<\/h3>\n
Let’s re-use the “BooksController<\/strong>” and “PressesController<\/strong>” from the ASP.NET Core OData now Available<\/a> and put them into the project. Now, the OData service is ready to test.<\/p>\n
For example, we can query a single book as by sending HTTP GET<\/em><\/strong> request at\u00a0“http:\/\/localhost:5000\/odata\/Books(1)<\/strong>“, the response has the following payload:<\/p>\n
{\r\n  \"@odata.context\":\u00a0\"http:\/\/localhost:5000\/odata\/$metadata#Books\/$entity\",\r\n  \"Id\":\u00a01,\r\n  \"ISBN\":\u00a0\"978-0-321-87758-1\",\r\n  \"Title\":\u00a0\"Essential\u00a0C#5.0\",\r\n  \"Author\":\u00a0\"Mark\u00a0Michaelis\",\r\n  \"Price\":\u00a059.99,\r\n  \"Location\":\u00a0{\r\n    \"City\":\u00a0\"Redmond\",\r\n    \"Street\":\u00a0\"156TH\u00a0AVE\u00a0NE\"\r\n  }\r\n}\r\n<\/pre>\n
That’s it.<\/p>\n
Multiple models<\/h2>\n
It’s easy to config multiple models in one OData service. Below is the sample codes that configures two models using different prefixes.<\/p>\n
IEdmModel model1 = GetEdmModel1();\r\nIEdmModel model2 = GetEdmModel2();\r\nservices.AddOData(opt => opt.AddModel(\"v1\", model1).AddModel(\"v2\", model2));\r\n<\/pre>\n
Where, “v1<\/strong>” and “v2<\/strong>” are the prefixes used before the OData path. It should be unique in one OData service.<\/p>\n
In this configuration, we can call the service using following request Uri:<\/p>\n