.Net核心Web每个控制器不同的JSON外壳

Question

我们正在尝试将一个旧的API迁移到当前的.Net核心Web中。当前API使用camelCasing返回JSON，但是我们的旧API使用PascalCasing，我们不想更新客户端。

是否有任何方法来指定我们希望每个控制器使用哪种序列化策略，而不是跨服务使用全局策略？

Answer 1

是的，您可以通过在控制器上使用属性来实现它。见下面的样本：

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
public class CustomJsonFormatter : ActionFilterAttribute
{
    private readonly string formatName = string.Empty;
    public CustomJsonFormatter(string _formatName)
    {
        formatName = _formatName;
    }

    public override void OnActionExecuted(ActionExecutedContext context)
    {
        if (context == null || context.Result == null)
        {
            return;
        }

        var settings = JsonSerializerSettingsProvider.CreateSerializerSettings();

        if (formatName == "camel")
        {
            settings.ContractResolver = new Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver();
        }            
        else
        {
            settings.ContractResolver = new Newtonsoft.Json.Serialization.DefaultContractResolver();
        }

        var formatter = new JsonOutputFormatter(settings, ArrayPool<Char>.Shared);

        (context.Result as Microsoft.AspNetCore.Mvc.OkObjectResult).Formatters.Add(formatter);
    }
}

这是你的控制器：

[CustomJsonFormatter("camel")]
[Route("api/[controller]")]
public class ValuesController : Controller
{
    // GET: api/values
    [HttpGet]
    public IActionResult Get()
    {
        Car car = new Car { Color = "red", Make = "Nissan" };

        return Ok(car);
    }        
}

Answer 2

我已经为OkObjectResult做了一个扩展方法，以便能够选择我不希望camel案例序列化行为的位置。你可以这样使用它：

OkObjectResult(yourResponseObject).PreventCamelCase();

以下是扩展方法：

public static OkObjectResult PreventCamelCase(this OkObjectResult response)
{
    var settings = JsonSerializerSettingsProvider.CreateSerializerSettings();
    settings.ContractResolver = new Newtonsoft.Json.Serialization.DefaultContractResolver();

    var formatter = new JsonOutputFormatter(settings, ArrayPool<Char>.Shared);
    response.Formatters.Add(formatter);
    return response;
}