ASP.NET Core返回带有状态码的JSON [英] ASP.NET Core return JSON with status code

问题描述

我正在寻找在.NET Core Web API控制器中以HTTP状态代码返回JSON的正确方法.我曾经这样使用它:

I'm looking for the correct way to return JSON with a HTTP status code in my .NET Core Web API controller. I use to use it like this:

public IHttpActionResult GetResourceData()
{
    return this.Content(HttpStatusCode.OK, new { response = "Hello"});
}

这是在4.6 MVC应用程序中，但是现在有了.NET Core，我似乎没有这个IHttpActionResult我有了ActionResult并像这样使用:

This was in a 4.6 MVC application but now with .NET Core I don't seem to have this IHttpActionResult I have ActionResult and using like this:

public ActionResult IsAuthenticated()
{
    return Ok(Json("123"));
}

但是来自服务器的响应很奇怪，如下图所示:

But the response from the server is weird, as in the image below:

我只希望Web API控制器像在Web API 2中一样返回带有HTTP状态代码的JSON.

I just want the Web API controller to return JSON with a HTTP status code like I did in Web API 2.

推荐答案

以JsonResult响应的最基本的版本是:

The most basic version responding with a JsonResult is:

// GET: api/authors
[HttpGet]
public JsonResult Get()
{
    return Json(_authorRepository.List());
}

但是，这不能解决您的问题，因为您不能显式处理自己的响应代码.

However, this isn't going to help with your issue because you can't explicitly deal with your own response code.

控制状态结果的方法是，您需要返回一个ActionResult，然后在其中可以利用StatusCodeResult类型.

The way to get control over the status results, is you need to return a ActionResult which is where you can then take advantage of the StatusCodeResult type.

例如:

// GET: api/authors/search?namelike=foo
[HttpGet("Search")]
public IActionResult Search(string namelike)
{
    var result = _authorRepository.GetByNameSubstring(namelike);
    if (!result.Any())
    {
        return NotFound(namelike);
    }
    return Ok(result);
}

请注意，以上两个示例均来自Microsoft文档提供的出色指南:格式化响应数据

Note both of these above examples came from a great guide available from Microsoft Documentation: Formatting Response Data

我经常遇到的问题是，我希望对我的WebAPI进行更精细的控制，而不是仅仅使用VS中新项目"模板中的默认配置.

The issue I come across quite often is that I wanted more granular control over my WebAPI rather than just go with the defaults configuration from the "New Project" template in VS.

让我们确保您掌握了一些基础知识...

Let's make sure you have some of the basics down...

为了使您的ASP.NET Core WebAPI在完全控制状态码的情况下响应JSON序列化对象，应首先确保在ConfigureServices方法中包括了AddMvc()服务.通常在Startup.cs中找到.

In order to get your ASP.NET Core WebAPI to respond with a JSON Serialized Object along full control of the status code, you should start off by making sure that you have included the AddMvc() service in your ConfigureServices method usually found in Startup.cs.

请注意，AddMvc()将自动包括JSON的输入/输出格式化程序以及对其他请求类型的响应.

It's important to note thatAddMvc() will automatically include the Input/Output Formatter for JSON along with responding to other request types.

如果您的项目需要完全控制，并且您想严格定义服务，例如您的WebAPI如何处理包括application/json在内的各种请求类型，而不响应其他请求类型(例如标准的浏览器请求)，您可以使用以下代码手动进行定义:

If your project requires full control and you want to strictly define your services, such as how your WebAPI will behave to various request types including application/json and not respond to other request types (such as a standard browser request), you can define it manually with the following code:

public void ConfigureServices(IServiceCollection services)
{
    // Build a customized MVC implementation, without using the default AddMvc(), instead use AddMvcCore().
    // https://github.com/aspnet/Mvc/blob/dev/src/Microsoft.AspNetCore.Mvc/MvcServiceCollectionExtensions.cs

    services
        .AddMvcCore(options =>
        {
            options.RequireHttpsPermanent = true; // does not affect api requests
            options.RespectBrowserAcceptHeader = true; // false by default
            //options.OutputFormatters.RemoveType<HttpNoContentOutputFormatter>();

            //remove these two below, but added so you know where to place them...
            options.OutputFormatters.Add(new YourCustomOutputFormatter()); 
            options.InputFormatters.Add(new YourCustomInputFormatter());
        })
        //.AddApiExplorer()
        //.AddAuthorization()
        .AddFormatterMappings()
        //.AddCacheTagHelper()
        //.AddDataAnnotations()
        //.AddCors()
        .AddJsonFormatters(); // JSON, or you can build your own custom one (above)
}

您会注意到，我还提供了一种添加您自己的自定义输入/输出格式器的方法，以防您可能想响应其他序列化格式(protobuf，thrift等).

You will notice that I have also included a way for you to add your own custom Input/Output formatters, in the event you may want to respond to another serialization format (protobuf, thrift, etc).

上面的代码大部分是AddMvc()方法的重复.但是，我们通过定义每个服务来自己实现每个默认"服务，而不是使用带有模板的预装服务.我已经在代码块中添加了存储库链接，或者您可以签出AddMvc()

The chunk of code above is mostly a duplicate of the AddMvc() method. However, we are implementing each "default" service on our own by defining each and every service instead of going with the pre-shipped one with the template. I have added the repository link in the code block, or you can check out AddMvc() from the GitHub repository..

请注意，有些指南将尝试通过撤消"默认值来解决此问题，而不是仅仅不首先实现它.如果考虑到这一点，我们现在正在使用Open来源，这是多余的工作，错误的代码，坦率地说是一个旧习惯，很快就会消失.

我将向您展示一个非常简单的方法，以使您的问题得到解决.

I'm going to show you a really straight-forward one just to get your question sorted.

public class FooController
{
    [HttpPost]
    public async Task<IActionResult> Create([FromBody] Object item)
    {
        if (item == null) return BadRequest();

        var newItem = new Object(); // create the object to return
        if (newItem != null) return Ok(newItem);

        else return NotFound();
    }
}

---

步骤3:检查您的Content-Type和Accept

您需要确保正确设置请求中的Content-Type和Accept标头.对于您的情况(JSON)，您需要将其设置为application/json.

---

Step 3: Check your Content-Type and Accept

You need to make sure that your Content-Type and Accept headers in your request are set properly. In your case (JSON), you will want to set it up to be application/json.

如果您希望您的WebAPI默认作为JSON响应，则无论请求标头指定什么内容，您都可以采用几种方式进行.

If you want your WebAPI to respond as JSON as default, regardless of what the request header is specifying you can do that in a couple ways.

方法1 如我之前推荐的文章中所述(格式化响应数据)，您可以在控制器/操作级别强制使用特定格式.我个人不喜欢这种方法...但是这里是为了完整性:

Way 1 As shown in the article I recommended earlier (Formatting Response Data) you could force a particular format at the Controller/Action level. I personally don't like this approach... but here it is for completeness:

强制使用特定格式如果您想限制特定操作的响应格式，则可以应用 [生产]过滤器. [生产]过滤器指定响应 特定操作(或控制器)的格式.像大多数过滤器一样， 可以在操作，控制器或全局范围内应用.

Forcing a Particular Format If you would like to restrict the response formats for a specific action you can, you can apply the [Produces] filter. The [Produces] filter specifies the response formats for a specific action (or controller). Like most Filters, this can be applied at the action, controller, or global scope.

[Produces("application/json")]
public class AuthorsController

[Produces]过滤器将强制执行 AuthorsController返回JSON格式的响应，即使其他 为应用程序配置了格式化程序，并提供了客户端 Accept标头，要求使用其他可用格式.

The [Produces] filter will force all actions within the AuthorsController to return JSON-formatted responses, even if other formatters were configured for the application and the client provided an Accept header requesting a different, available format.

方法2 我的首选方法是使WebAPI以请求的格式响应所有请求.但是，如果它不接受请求的格式，则后备为默认格式(即JSON)

Way 2 My preferred method is for the WebAPI to respond to all requests with the format requested. However, in the event that it doesn't accept the requested format, then fall-back to a default (ie. JSON)

首先，您需要在选项中进行注册(如前所述，我们需要重做默认行为)

First, you'll need to register that in your options (we need to rework the default behavior, as noted earlier)

options.RespectBrowserAcceptHeader = true; // false by default

最后，只需简单地对服务构建器中定义的格式器列表进行重新排序，Web主机将默认使用您位于列表顶部(即位置0)的格式器.

Finally, by simply re-ordering the list of the formatters that were defined in the services builder, the web host will default to the formatter you position at the top of the list (ie position 0).

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