How to customize all response in .Net Core?

Question

Im using .Net Core to write a json api server, so I need customize all response to like:

public class Result {
    public int Code { get; set; }
    public string Message { get; set; }
    public object Data { get; set; }
}

as

{
    "code": 1,
    "message": "success",
    "data": ...
}

For some response(or exception), I can using IResultFilter(or IExceptionFilter) to format the response body:

public class ResultFilter : IResultFilter {
    public void OnResultExecuted(ResultExecutedContext context) {
    }

    public void OnResultExecuting(ResultExecutingContext context) {
        context.Result = new JsonResult(new Result());
    }
}

But in some case(like 400, 404 and 415), it would not be enter the Filter and will return directily.

I was try to use Middleware, but it could not hold them too.

So I want to catch all error and format it like ExceptionFilter, how can I do?

Answer 1

ExceptionFilter can only handle server-side exceptions. Do you find that the case can't be enter the Filter are all 4xx error, They are all client-side exceptions, So you can use UseStatusCodePages to handle these exceptions:

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseStatusCodePages(async statusCodeContext =>
{
    // using static System.Net.Mime.MediaTypeNames;
    statusCodeContext.HttpContext.Response.ContentType = "application/json";

    switch (statusCodeContext.HttpContext.Response.StatusCode)
    {
        
            await statusCodeContext.HttpContext.Response.WriteAsync(
                JsonConvert.SerializeObject(result415)
        );
            
            break;
        case 404:
            var result = new Result {
                Code = 404,
                Message = "Not Found",
                Data = "......"
            };
            await statusCodeContext.HttpContext.Response.WriteAsync(
                JsonConvert.SerializeObject(result)
        ) ;
            break;
    }

});
//......