如何从Azure函数返回JSON

本文关键字：返回 JSON 函数 Azure | 更新日期: 2023-09-27 18:02:25

我正在玩Azure函数。然而，我觉得我被一些非常简单的事情难住了。我试图找出如何返回一些基本的JSON。我不确定如何创建一些JSON并将其返回到我的请求。

从前，我会创建一个对象，填充它的属性，并序列化它。所以，我从这条路径开始:

#r "Newtonsoft.Json"
using System.Net;
public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)
{
    log.Info($"Running Function");    
    try {      
      log.Info($"Function ran");
      var myJSON = GetJson();
      // I want myJSON to look like:
      // {
      //   firstName:'John',
      //   lastName: 'Doe',
      //   orders: [
      //     { id:1, description:'...' },
      //     ...
      //   ]
      // }
      return ?;
    } catch (Exception ex) {
        // TODO: Return/log exception
        return null;
    }
}
public static ? GetJson() 
{
  var person = new Person();
  person.FirstName = "John";
  person.LastName = "Doe";
  person.Orders = new List<Order>();
  person.Orders.Add(new Order() { Id=1, Description="..." });
  ?
}
public class Person 
{
  public string FirstName { get; set; }
  public string LastName { get; set; }
  public List<Order> Orders { get; set; }
}
public class Order
{
  public int Id { get; set; }
  public string Description { get; set; }
}

但是，我现在完全被序列化和返回过程卡住了。我想我已经习惯了在ASP中返回JSON。. NET MVC，一切都是Action

如何从Azure函数返回JSON

下面是一个完整的Azure函数示例，它返回一个格式正确的JSON对象，而不是XML:

#r "Newtonsoft.Json"
using System.Net;
using Newtonsoft.Json;
using System.Text;
public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)
{
    var myObj = new {name = "thomas", location = "Denver"};
    var jsonToReturn = JsonConvert.SerializeObject(myObj);
    return new HttpResponseMessage(HttpStatusCode.OK) {
        Content = new StringContent(jsonToReturn, Encoding.UTF8, "application/json")
    };
}

在浏览器中导航到端点，您将看到:

{
  "name": "thomas",
  "location": "Denver"
}

最简单的方法可能是

public static async Task<IActionResult> Run(
    [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "/jsontestapi")] HttpRequest req,
    ILogger log)
{
    return new JsonResult(resultObject);
}

将内容类型设置为application/json，并在响应体中返回json。

您可以从

获取req
public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)

并使用

创建响应
return req.CreateResponse(HttpStatusCode.OK, json, "application/json");

或汇编System.Web.Http中的任何其他过载。

关于learn.microsoft.com的更多信息

看起来这可以通过使用"application/json"媒体类型来实现，而不需要显式地将Person与Newtonsoft.Json序列化。

这是完整的工作样本，结果Chrome为:

{"FirstName":"John","LastName":"Doe","Orders":[{"Id":1,"Description":"..."}]}

代码如下:

[FunctionName("StackOverflowReturnJson")]
    public static HttpResponseMessage Run([HttpTrigger("get", "post", Route = "StackOverflowReturnJson")]HttpRequestMessage req, TraceWriter log)
    {
        log.Info($"Running Function");
        try
        {
            log.Info($"Function ran");
            var myJSON = GetJson();  // Note: this actually returns an instance of 'Person' 
            // I want myJSON to look like:
            // {
            //   firstName:'John',
            //   lastName: 'Doe',
            //   orders: [
            //     { id:1, description:'...' },
            //     ...
            //   ]
            // }
            var response = req.CreateResponse(HttpStatusCode.OK, myJSON, JsonMediaTypeFormatter.DefaultMediaType); // DefaultMediaType = "application/json" does the 'trick'
            return response;
        }
        catch (Exception ex)
        {
            // TODO: Return/log exception
            return null;
        }
    }
    public static Person GetJson()
    {
        var person = new Person();
        person.FirstName = "John";
        person.LastName = "Doe";
        person.Orders = new List<Order>();
        person.Orders.Add(new Order() { Id = 1, Description = "..." });
        return person;
    }
    public class Person
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public List<Order> Orders { get; set; }
    }
    public class Order
    {
        public int Id { get; set; }
        public string Description { get; set; }
    }

JSON非常简单，Newtonsoft。Json库是一个特例。您可以通过在脚本文件的顶部添加以下内容来包含它:

#r "Newtonsoft.Json"
using Newtonsoft.Json;

则函数变为:

public static string GetJson() 
{
  var person = new Person();
  person.FirstName = "John";
  person.LastName = "Doe";
  person.Orders = new List<Order>();
  person.Orders.Add(new Order() { Id=1, Description="..." });
  return JsonConvert.SerializeObject(person);
}

您可以将方法签名更改为:

public static async Task<object> Run(HttpRequestMessage req, TraceWriter log)

我有一个类似的问题，这似乎是最受欢迎的帖子没有答案。在确定了节点的作用之后，下面的代码应该可以工作，并为您提供您所需要的东西。其他示例仍然返回字符串表示形式，而这将返回JSON。

请记住声明using System.Text;还要加上:

return JsonConvert.SerializeObject(person);

到GetJson函数。

    return new HttpResponseMessage(HttpStatusCode.OK)
       {
           Content = new StringContent(GetJson(), Encoding.UTF8, "application/json")
       };

#r "Newtonsoft.Json"
using System.Net;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json;
public static IActionResult Run(HttpRequest req, ILogger log)
{    
    (string name, string surname) = ("James", "Ozzy");
    return new ObjectResult(new { name, surname }) ;
 }

您可以创建所有者响应:

 var response = new HttpResponseMessage(HttpStatusCode.OK) { 
                Content = json
            };
 return new ObjectResult(response);

如果您既不使用Newtonsoft.Json也不使用System.Web.Http(如本答案)

var msg = new Msg("Hello, World");
var response = req.CreateResponse(HttpStatusCode.OK);
response.WriteAsJsonAsync(msg);
return response;
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