500 Internal Server Error instead of 400 bad request

I have a request that has a property called HouseNumber which is optional.

public class SearchRequest
{
    public string? Prefix { get; set; }
    public string? Surname { get; set; } = null!;
    public DateTime? DateOfBirth { get; set; }
    public string? PostalCode { get; set; } = null!;
    public int? HouseNumber { get; set; }

}

When I send a request like below, which houseNumber is a string instead of int

{
  "prefix": "sample prefix",
  "surname": "my surname",
  "postalCode": "1111SR",
  "houseNumber": "SR55"
}

I got this exception with a 500 Internal Server error.

System.Text.Json.JsonException: The JSON value could not be converted to System.Nullable`1[System.Int32]. Path: $.houseNumber | LineNumber: 5 | BytePositionInLine: 23.
 ---> System.FormatException: Either the JSON value is not in a supported format, or is out of bounds for an Int32.
   at System.Text.Json.ThrowHelper.ThrowFormatException(NumericType numericType)
   at System.Text.Json.Utf8JsonReader.GetInt32WithQuotes()
   at System.Text.Json.Serialization.Converters.NullableConverter`1.ReadNumberWithCustomHandling(Utf8JsonReader& reader, JsonNumberHandling numberHandling, JsonSerializerOptions options)
   at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   at System.Text.Json.Serialization.Metadata.JsonPropertyInfo`1.ReadJsonAndSetMember(Object obj, ReadStack& state, Utf8JsonReader& reader)
   at System.Text.Json.Serialization.Converters.ObjectDefaultConverter`1.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   at System.Text.Json.Serialization.JsonConverter`1.ReadCore(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
   --- End of inner exception stack trace ---
   at System.Text.Json.ThrowHelper.ReThrowWithPath(ReadStack& state, Utf8JsonReader& reader, Exception ex)
   at System.Text.Json.Serialization.JsonConverter`1.ReadCore(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
   at System.Text.Json.Serialization.JsonConverter`1.ReadCoreAsObject(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
   at System.Text.Json.JsonSerializer.ReadCore[TValue](Utf8JsonReader& reader, JsonTypeInfo jsonTypeInfo, ReadStack& state)
   at System.Text.Json.JsonSerializer.ContinueDeserialize[TValue](ReadBufferState& bufferState, JsonReaderState& jsonReaderState, ReadStack& readStack, JsonTypeInfo jsonTypeInfo)
   at System.Text.Json.JsonSerializer.ReadFromStreamAsync[TValue](Stream utf8Json, JsonTypeInfo jsonTypeInfo, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Http.HttpRequestJsonExtensions.ReadFromJsonAsync(HttpRequest request, Type type, JsonSerializerOptions options, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Http.HttpRequestJsonExtensions.ReadFromJsonAsync(HttpRequest request, Type type, JsonSerializerOptions options, CancellationToken cancellationToken)
   at FastEndpoints.RequestBinder`1.BindJsonBody(HttpRequest httpRequest, JsonSerializerContext serializerCtx, CancellationToken cancellation)
   at FastEndpoints.RequestBinder`1.BindAsync(BinderContext ctx, CancellationToken cancellation)
   at FastEndpoints.Endpoint`2.ExecAsync(CancellationToken ct)
   at FastEndpoints.Endpoint`2.ExecAsync(CancellationToken ct)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)

I think since the input is not valid it should be 400 bad request, Am I right? or I’m missing something

[dj-nitehawk]

thanks for pushing me to look in to it 😉

[itsoli91]

Thank you!