model validation for webapi

Model validation in ASP.NET Core MVC and Razor Pages

ModelStateInvalidFilter Class

webapi:Create web APIs with ASP.NET Core

Automatic HTTP 400 responses

The [ApiController] attribute makes model validation errors automatically trigger an HTTP 400 response. Consequently, the following code is unnecessary in an action method:

C#Copy

 

if (!ModelState.IsValid)
{
    return BadRequest(ModelState);
}

ASP.NET Core MVC uses the ModelStateInvalidFilter action filter to do the preceding check.

Default BadRequest response

With a compatibility version of 2.1, the default response type for an HTTP 400 response is SerializableError. The following request body is an example of the serialized type:

JSONCopy

 

{
  "": [
    "A non-empty request body is required."
  ]
}

With a compatibility version of 2.2 or later, the default response type for an HTTP 400 response is ValidationProblemDetails. The following request body is an example of the serialized type:

JSONCopy

 

{
  "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "traceId": "|7fb5e16a-4c8f23bbfc974667.",
  "errors": {
    "": [
      "A non-empty request body is required."
    ]
  }
}

The ValidationProblemDetails type:

• Provides a machine-readable format for specifying errors in web API responses.
• Complies with the RFC 7807 specification.

Log automatic 400 responses

See How to log automatic 400 responses on model validation errors (aspnet/AspNetCore.Docs #12157).

Customizing automatic HTTP 400 error response in ASP.NET Core Web APIs

 

 

//中间件定义
    public class ValidatorActionFilter : IActionFilter
    {
        public void OnActionExecuting(ActionExecutingContext filterContext)
        {
            if (!filterContext.ModelState.IsValid)
            {
                var result = new OAProxyOPResult();
                var invalidExceptionContent = ConstructErrorMessages(filterContext.ModelState);
                var exception = new OAProxyException(Base.OAProxyOpResultCode.ParameterInvalid, JsonConvert.SerializeObject(invalidExceptionContent));
                result.Result = exception.ResultCode;
                result.ResultContent = exception;
                filterContext.Result = new JsonResult(result);
                //filterContext.Result = new BadRequestObjectResult(filterContext.ModelState);
            }
        }

        private Dictionary<string, string[]> ConstructErrorMessages(ModelStateDictionary modelState)
        {
            var errorsResult = new Dictionary<string, string[]>();
            foreach (var keyModelStatePair in modelState)
            {
                var key = keyModelStatePair.Key;
                var errors = keyModelStatePair.Value.Errors;
                if (errors != null && errors.Count > 0)
                {
                    if (errors.Count == 1)
                    {
                        var errorMessage = GetErrorMessage(errors[0]);
                        errorsResult.Add(key, new[] { errorMessage });
                    }
                    else
                    {
                        var errorMessages = new string[errors.Count];
                        for (var i = 0; i < errors.Count; i++)
                        {
                            errorMessages[i] = GetErrorMessage(errors[i]);
                        }

                        errorsResult.Add(key, errorMessages);
                    }
                }
            }
            return errorsResult;
        }

        string GetErrorMessage(ModelError error)
        {
            return string.IsNullOrEmpty(error.ErrorMessage) ? "The input was not valid." : error.ErrorMessage;
        }

        public void OnActionExecuted(ActionExecutedContext filterContext)
        {

        }

　　

            //startup中添加
            services.AddControllers(config =>
            {
                config.Filters.Add(typeof(ValidatorActionFilter));

            })

　　

 https://stackoverflow.com/questions/49646688/custom-middleware-for-input-validation