[英]Configure input/output formatters on controllers with ASP.NET Core 2.1
I am in the process of rewriting an old ASP.NET WebAPI 2.1 project to ASP.NET Core MVC 2.1.我正在将旧的 ASP.NET WebAPI 2.1 项目重写为 ASP.NET Core MVC 2.1。 One of the problem I am facing is about porting the old behavior of the service which configure the input and output formatters through custom attributes whom implement IControllerConfiguration interface.
我面临的问题之一是移植服务的旧行为,这些行为通过实现 IControllerConfiguration 接口的自定义属性来配置输入和输出格式化程序。 I have not been able to find a replacement for this interface nor any alternative to configure formatters on controller-basis, other than injecting them at global level with the AddMvc(options) method.
除了使用 AddMvc(options) 方法在全局级别注入它们之外,我无法找到此接口的替代品,也找不到任何替代方案来配置基于控制器的格式化程序。
I haven't found anything that can be configured at the controller level, but I did find a solution that involves changes to each action where you need this functionality.我还没有找到任何可以在控制器级别进行配置的内容,但我确实找到了一个解决方案,该解决方案涉及对需要此功能的每个操作进行更改。 In my case I needed to customize the JSON serializer settings, which can be done like this for the output:
在我的情况下,我需要自定义 JSON 序列化器设置,可以像这样输出:
[HttpGet]
public IActionResult Get()
{
...
return Json(result, _serializerSettings);
}
and like this for input:像这样输入:
[HttpPost]
public IActionResult Post([FromBodyCustomSerializationSettings]MyPostDto postDto)
{
...
}
class FromBodyCustomSerializationSettingsAttribute : ModelBinderAttribute
{
public FromBodyCustomSerializationSettingsAttribute() : base(typeof(MyModelBinder))
{
BindingSource = BindingSource.Body;
}
}
class MyModelBinder : IModelBinder
{
private readonly BodyModelBinder _bodyModelBinder;
public MyModelBinder(IHttpRequestStreamReaderFactory readerFactory, ILoggerFactory loggerFactory, IOptions<MvcOptions> options, IOptions<MvcJsonOptions> jsonOptions, ArrayPool<char> charPool, ObjectPoolProvider objectPoolProvider)
{
var formatters = options.Value.InputFormatters.ToList();
int jsonFormatterIndex = formatters.FirstIndexOf(formatter => formatter is JsonInputFormatter);
JsonSerializerSettings myCustomSettings = ...
formatters[jsonFormatterIndex] = new JsonInputFormatter(loggerFactory.CreateLogger("MyCustomJsonFormatter"), myCustomSettings, charPool, objectPoolProvider, options.Value, jsonOptions.Value);
_bodyModelBinder = new BodyModelBinder(formatters, readerFactory, loggerFactory, options.Value);
}
public Task BindModelAsync(ModelBindingContext bindingContext)
{
return _bodyModelBinder.BindModelAsync(bindingContext);
}
}
Actually I found a way.其实我找到了办法。 I created an attribute which also implements IResultFilter and here is the OnResultExecuting method, where the magic happens:
我创建了一个也实现了 IResultFilter 的属性,这里是 OnResultExecuting 方法,魔法发生的地方:
public void OnResultExecuting(ResultExecutingContext context)
{
var objectResult = context.Result as ObjectResult;
if (objectResult != null)
{
var serializerSettings = new JsonSerializerSettings
{
ContractResolver = new DefaultContractResolver()
};
var jsonFormatter = new JsonOutputFormatter(
serializerSettings,
ArrayPool<char>.Shared);
objectResult.Formatters.Add(jsonFormatter);
}
}
Basically here I am injecting a custom JSON formatter in every object result, before it is sent to the client.基本上在这里,我在每个对象结果中注入一个自定义 JSON 格式化程序,然后再将其发送到客户端。 It appears (but I did not find any documentation about this) that in this way ASP.NET Core MVC prefers the injected formatter over the globally defined one.
看起来(但我没有找到任何关于此的文档),ASP.NET Core MVC 以这种方式更喜欢注入的格式化程序而不是全局定义的格式化程序。
I hopes it helps other because I was struggling on this...我希望它可以帮助其他人,因为我在这方面苦苦挣扎...
In order to be able to use @dcstraw's code in ASP .Net Core 3.1, I needed to modify MyModelBinder
implementation slightly:为了能够在 ASP .Net Core 3.1 中使用 @dcstraw 的代码,我需要稍微修改
MyModelBinder
实现:
class MyModelBinder : IModelBinder
{
private readonly BodyModelBinder _bodyModelBinder;
public MyModelBinder(IHttpRequestStreamReaderFactory readerFactory, ILoggerFactory loggerFactory, IOptions<MvcOptions> options, IOptions<MvcNewtonsoftJsonOptions> jsonOptions, ArrayPool<char> charPool, ObjectPoolProvider objectPoolProvider)
{
var formatters = options.Value.InputFormatters.ToList();
int jsonFormatterIndex = formatters.FindIndex(formatter => formatter is NewtonsoftJsonInputFormatter);
JsonSerializerSettings myCustomSettings = ...
formatters[jsonFormatterIndex] = new NewtonsoftJsonInputFormatter(loggerFactory.CreateLogger("MyCustomJsonFormatter"), myCustomSettings, charPool, objectPoolProvider, options.Value, jsonOptions.Value);
_bodyModelBinder = new BodyModelBinder(formatters, readerFactory, loggerFactory, options.Value);
}
public Task BindModelAsync(ModelBindingContext bindingContext)
{
return _bodyModelBinder.BindModelAsync(bindingContext);
}
}
Basically :基本上:
JsonInputFormatter
changes into NewtonsoftJsonInputFormatter
JsonInputFormatter
变成NewtonsoftJsonInputFormatter
MvcJsonOptions
changes into MvcNewtonsoftJsonOptions
MvcJsonOptions
更改为MvcNewtonsoftJsonOptions
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