Swagger Operation Filter to handle FormData

FormDataOperationFilter.cs

// Usage:
// 1. Install-Package MultipartDataMediaFormatter.V2
// 2. Alter Swagger Config
//    c.OperationFilter<FormDataOperationFilter>();
// 3. Annotate method you want to expose with multipart/form-data with [SwaggerMultipartAnnotatorAttribute]

public class FormDataOperationFilter : IOperationFilter
{
    public void Apply(Operation operation, SchemaRegistry schemaRegistry, ApiDescription apiDescription)
    {
        bool isMultipart = apiDescription.ActionDescriptor.GetCustomAttributes<SwaggerMultipartAnnotatorAttribute>().Any();

        if (isMultipart)
        {
            operation.consumes.Add("multipart/form-data");

            var parameters = new List<Parameter>();

            operation.parameters = parameters;

            foreach (var p in apiDescription.ActionDescriptor.GetParameters())
            {
                bool isFromBody = p.GetCustomAttributes<FromBodyAttribute>().Any();

                if (isFromBody)
                {
                    var properties = p.ParameterType.GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.SetProperty);

                    foreach (var prop in properties)
                    {
                        string type;

                        if (prop.PropertyType.Equals(typeof(HttpFile)))
                        {
                            type = "file";
                        } else
                        {
                            var registry = schemaRegistry.GetOrRegister(prop.PropertyType);
                            type = registry.type;
                        }

                        bool isRequired = prop.GetCustomAttributes<RequiredAttribute>().Any();

                        parameters.Add(
                            new Parameter
                            {
                                name = ToCamelCase(prop.Name),
                                @in = "formData",
                                type = type,
                                required = isRequired,
                            });
                    }
                } else
                {
                    var registry = schemaRegistry.GetOrRegister(p.ParameterType);

                    parameters.Add(new Parameter
                    {
                        name = p.ParameterName,
                        @in = "query",
                        type = registry.type,
                        required = !p.IsOptional,
                    });
                }
            }
        }
    }

    private static string ToCamelCase(string value)
    {
        if (string.IsNullOrEmpty(value))
            return value;

        return value.Substring(0, 1).ToLowerInvariant() + value.Substring(1);
    }
}

SwaggerMultipartAnnotatorAttribute.cs

[AttributeUsage(AttributeTargets.Method)]
public class SwaggerMultipartAnnotatorAttribute : Attribute
{
}