在 ASP.NET Core MVC 中自定义响应序列化

Customizing response serialization in ASP.NET Core MVC(在 ASP.NET Core MVC 中自定义响应序列化)

问题描述

是否可以自定义在 ASP.NET Core MVC 中将类型序列化为响应的方式?

Is it possible to customize the way types are serialized to the response in ASP.NET Core MVC?

在我的特定用例中，我有一个结构 AccountId，它简单地包裹着一个 Guid:

In my particular use case I've got a struct, AccountId, that simply wraps around a Guid:

public readonly struct AccountId
{
    public Guid Value { get; }

    // ... 
}

当我从动作方法返回它时，不出所料，它会序列化为以下内容:

When I return it from an action method, unsurprisingly, it serializes to the following:

{ "value": "F6556C1D-1E8A-4D25-AB06-E8E244067D04" }

相反，我想自动解开 Value 以便它序列化为纯字符串:

Instead, I'd like to automatically unwrap the Value so it serializes to a plain string:

"F6556C1D-1E8A-4D25-AB06-E8E244067D04"

可以配置 MVC 来实现这一点吗?

Can MVC be configured to achieve this?

推荐答案

您可以使用 自定义转换器.

在你的情况下，它看起来像这样:

In your case, it would look like this:

[JsonConverter(typeof(AccountIdConverter))]
public readonly struct AccountId
{
    public Guid Value { get; }

    // ... 
}

public class AccountIdConverter : JsonConverter
{
    public override bool CanConvert(Type objectType)
        => objectType == typeof(AccountId);

    // this converter is only used for serialization, not to deserialize
    public override bool CanRead => false;

    // implement this if you need to read the string representation to create an AccountId
    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        => throw new NotImplementedException();

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        if (!(value is AccountId accountId))
            throw new JsonSerializationException("Expected AccountId object value.");

        // custom response 
        writer.WriteValue(accountId.Value);
    }
}

如果您不想使用 JsonConverter 属性，可以在 ConfigureServices 中添加转换器(需要 Microsoft.AspNetCore.Mvc.Formatters.Json):

public void ConfigureServices(IServiceCollection services)
{
    services
        .AddMvc()
        .AddJsonOptions(options => {
            options.SerializerSettings.Converters.Add(new AccountIdConverter());
        });
}