Intercept webapi json formatting errors

问题:

I'd like to have a way to intercept the exception that occurs when you send in malformed json to a webapi endpoint, so that I can return a semantic error code as opposed to just 500. (e.g. "Fix your broken JSON or go to hell")

回答1:

You can create your custom validation filter attribute by deriving from ActionFilterAttribute:

public class ValidationFilterAttribute : ActionFilterAttribute {     public override void OnActionExecuting(HttpActionContext actionContext)     {         if (!actionContext.ModelState.IsValid)         {             actionContext.Response = actionContext                                      .Request                                      .CreateErrorResponse(HttpStatusCode.BadRequest,                                                           actionContext.ModelState);         }     } } 

Now, you may either decorate your actions with it:

[HttpGet] [ValidationFilter()] public string DoSomethingCool() 

or register it globally via your config:

config.Filters.Add(new ValidationFilterAttribute()); 

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