Allow Content Security Policy logging.

[malylemire1]

It would be nice to have nicely displayed page for content security policy errors.

For now I use something like this

[HttpPost("~/cspreport")]
       public IActionResult CspReport([FromBody] CspReportRequest request)
       {
           this.LogParams((nameof(CspReportRequest), request));

           HttpContext.RaiseError(new ContentSecurityPolicyException(request));

           return Ok();
       }
   }

   [Serializable]
   public class ContentSecurityPolicyException : Exception
   {
       /// <summary>
       /// Default constructor.
       /// </summary>
       public ContentSecurityPolicyException(CspReportRequest request)
           : base($"Content Security Policy: {request.CspReport.DocumentUri} ({request.CspReport.ViolatedDirective})")
       {
       }
   }

   public class CspReportRequest
   {
       [JsonProperty(PropertyName = "csp-report")]
       public CspReport CspReport { get; set; }
   }
   public class CspReport
   {
       [JsonProperty(PropertyName = "document-uri")]
       public string DocumentUri { get; set; }

       [JsonProperty(PropertyName = "referrer")]
       public string Referrer { get; set; }

       [JsonProperty(PropertyName = "violated-directive")]
       public string ViolatedDirective { get; set; }

       [JsonProperty(PropertyName = "effective-directive")]
       public string EffectiveDirective { get; set; }

       [JsonProperty(PropertyName = "original-policy")]
       public string OriginalPolicy { get; set; }

       [JsonProperty(PropertyName = "blocked-uri")]
       public string BlockedUri { get; set; }

       [JsonProperty(PropertyName = "status-code")]
       public int StatusCode { get; set; }
   }

services.Configure<MvcOptions>(options =>
           {
               var formatter = options.InputFormatters.OfType<NewtonsoftJsonInputFormatter>().LastOrDefault();
               formatter.SupportedMediaTypes
                   .Add(MediaTypeHeaderValue.Parse("application/csp-report"));
           });