C#•2mo ago

✅ .NET 8 enum to string serialization throws an exception

Hello, Following the docs, a custom JsonSerializerContext is applied on the controllers, yet an exception is thrown.

c#
public sealed record GetLinkMetricsRequest
{
    [FromRoute]
    public string Id { get; set; }
    
    [FromQuery]
    public TimePeriodUnit? TimeUnit { get; set; } = TimePeriodUnit.Day;
    
    [FromQuery]
    public int? Units { get; set; }
}

[JsonSourceGenerationOptions(UseStringEnumConverter = true)]
[JsonSerializable(typeof(GetLinkMetricsRequest))]
public partial class TimePeriodUnitJsonContext : JsonSerializerContext;


// applied to the Controllers
var options = new JsonSerializerOptions
{
    TypeInfoResolver = JsonTypeInfoResolver.Combine(ContextA.Default, ContextB.Default, ContextC.Default);
};

c#
public sealed record GetLinkMetricsRequest
{
    [FromRoute]
    public string Id { get; set; }
    
    [FromQuery]
    public TimePeriodUnit? TimeUnit { get; set; } = TimePeriodUnit.Day;
    
    [FromQuery]
    public int? Units { get; set; }
}

[JsonSourceGenerationOptions(UseStringEnumConverter = true)]
[JsonSerializable(typeof(GetLinkMetricsRequest))]
public partial class TimePeriodUnitJsonContext : JsonSerializerContext;


// applied to the Controllers
var options = new JsonSerializerOptions
{
    TypeInfoResolver = JsonTypeInfoResolver.Combine(ContextA.Default, ContextB.Default, ContextC.Default);
};

The exception:

An unexpected error occurred. See the inner exception for details. System.NotSupportedException: JsonTypeInfo metadata for type 'AnalyticsService.Api..' was not provided by TypeInfoResolver of type 'System.Text.Json.Serialization.Metadata.JsonTypeInfoResolverWithAddedModifiers'. If using source generation, ensure that all root types passed to the serializer have been annotated with 'JsonSerializableAttribute', along with any types that might be serialized polymorphically.

An unexpected error occurred. See the inner exception for details. System.NotSupportedException: JsonTypeInfo metadata for type 'AnalyticsService.Api..' was not provided by TypeInfoResolver of type 'System.Text.Json.Serialization.Metadata.JsonTypeInfoResolverWithAddedModifiers'. If using source generation, ensure that all root types passed to the serializer have been annotated with 'JsonSerializableAttribute', along with any types that might be serialized polymorphically.

I have followed the docs: https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/source-generation#combine-source-generators https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/source-generation#blanket-policy

How to use source generation in System.Text.Json - .NET

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9 Replies

Pobiega•2mo ago

'AnalyticsService.Api..' doesn't strike me as a valid type identifier especially that double dot at the end is mighty suspicious whats the fully qualified name for GetLinkMetricsRequest?

CoreOP•2mo ago

sorry, I had no idea that's relevant

c#
'AnalyticsService.Api.Features.LinkMetrics.Models.GetLinkMetricsResult`1[AnalyticsService.Api.Features.LinkMetrics.Models.LinkClicksByDateResult]'

c#
'AnalyticsService.Api.Features.LinkMetrics.Models.GetLinkMetricsResult`1[AnalyticsService.Api.Features.LinkMetrics.Models.LinkClicksByDateResult]'

Pobiega•2mo ago

ok so its in that namespace at least but that seems to be a generic version? GetLinkMetricsResult<T>

CoreOP•2mo ago

That's being returned, specifically GetLinkMetricsResult<LinkClicksByDateResult>

c#
public class GetLinkMetricsResult<T>
{
    public IEnumerable<T> Metrics { get; set; } = null!;
}

public class LinkClicksByDateResult : ILinkMetricsResult
{
    public int Clicks { get; set; }
    public LocalDate Date { get; set; }
}

c#
public class GetLinkMetricsResult<T>
{
    public IEnumerable<T> Metrics { get; set; } = null!;
}

public class LinkClicksByDateResult : ILinkMetricsResult
{
    public int Clicks { get; set; }
    public LocalDate Date { get; set; }
}

But there is no enum being used here and it is the response

Pobiega•2mo ago

but that type is what the serializer cant serialize thats the error you are getting meaning it (probably) handles the request fine, its the result thats failing

CoreOP•2mo ago

Yes, the result is failing the request is serialized

Pobiega•2mo ago

okay, so add the result type to your serializer context?

CoreOP•2mo ago

Now it works, thank you, I still don't understand what has the response to do with the serializer $close

MODiX•2mo ago

If you have no further questions, please use /close to mark the forum thread as answered

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✅ .NET 8 enum to string serialization throws an exception