我们知道Asp.net Core是支持输出为Json格式的。同时也支持输出为xml格式。只要我们正确的配置。并在Request时指定正确的Accept，即可根据不同的Header来输出不同的格式.
前几天看Jessite4.0读其日志，又看到这段文字
所有连接加 .json 或 .xml 或增加 __ajax=json 参数，或增加 __ajax=xml 参数，则自动返回 json 或 xml 数据，而不返回视图于是在想，我们能不能提供下Asp.net Core中这种功能。最笨的办法，当然是在每个API返回时，判断下有没有这个参数。话说回来，既然是每个请教都需要判断，那么，最简单的办法是不是使用Middleware？
实现原理就是，对请求中是否有类似于_ajax参数进行判断，有之后，根据参数值选用不同的Accept.
实现
????public class SerializationMiddleware ???{ ????????private readonly RequestDelegate _next; ????????private readonly SerializationOption _option; ?????????public SerializationMiddleware(RequestDelegate next,SerializationOption option) ???????{ ???????????_next = next; ???????????_option = option; ????????} ????????public async Task InvokeAsync(HttpContext context) ???????{ ???????????var servalue = context.Request.Query[_option.QueryName]; ????????????if (_option.SerializeJson && !string.IsNullOrEmpty(servalue)) ???????????{ ???????????????if (servalue == "json") ???????????????{ ???????????????????context.Request.ContentType = "application/json"; ???????????????????context.Request.Headers["Accept"]= "application/json"; ???????????????} ???????????????if (servalue == "xml") ???????????????{ ????????????????????context.Request.ContentType = "text/xml, application/xml"; ???????????????????context.Request.Headers["Accept"] = " application/xml,text/xml"; ????????????????} ???????????} ??????????????await _next.Invoke(context); ???????} ???} ?/// <summary>/// 序列化选项/// 是否序化Json/Xml/// </summary>public class SerializationOption{ ???public string QueryName { get; set; } = "queryType"; ???public bool SerializeJson { get; set; } = false; ???public bool SerializeXml { get; set; } = false;} ?当我们完成SerializationMiddleware，我们可以将调用包装下
????????public static IMvcBuilder AddSerialization(this IMvcBuilder builder) ???????{ ????????????return builder.AddXmlSerializerFormatters(); ????????} ?????????public static IApplicationBuilder UseSerialization(this IApplicationBuilder builder,SerializationOption option) ???????{ ????????????return builder.UseMiddleware<SerializationMiddleware>(option); ????????}我们在Startup.cs中使用
//先是在ConfigureServices(IServiceCollection services)services.AddMvc(options => ???????????{ ???????????????//options.RespectBrowserAcceptHeader = true; // false by default ???????????????options.OutputFormatters.Add(new XmlSerializerOutputFormatter()); ???????????}) ???????????.AddSerialization(); //在Configure(IApplicationBuilder app, IHostingEnvironment env) app.UseSerialization(new SerializationOption { SerializeJson = true, SerializeXml = true });后续
我们当然可以将SerializationOption做成IOtion<>形式的，可以在其它地方查看其值。只是感觉上并没有多大的意义
使Asp.net Core同时支持输出Json/Xml
原文地址：https://www.cnblogs.com/startewho/p/8856497.html