Swagger UI Web Api documentation Present enums as

Question

Is there a way to display all enums as their string value in swagger instead of their int value?

I want to be able to submit POST actions and put enums according to their string value without having to look at the enum every time.

I tried DescribeAllEnumsAsStrings but the server then receives strings instead of the enum value which is not what we're looking for.

Has anyone solved this?

Edit:

public class Letter 
{
    [Required]
    public string Content {get; set;}

    [Required]
    [EnumDataType(typeof(Priority))]
    public Priority Priority {get; set;}
}


public class LettersController : ApiController
{
    [HttpPost]
    public IHttpActionResult SendLetter(Letter letter)
    {
        // Validation not passing when using DescribeEnumsAsStrings
        if (!ModelState.IsValid)
            return BadRequest("Not valid")

        ..
    }

    // In the documentation for this request I want to see the string values of the enum before submitting: Low, Medium, High. Instead of 0, 1, 2
    [HttpGet]
    public IHttpActionResult GetByPriority (Priority priority)
    {

    }
}


public enum Priority
{
    Low, 
    Medium,
    High
}

Answer 1

if anyone is interested i have modified the code to work with

.NET CORE 3 and Swagger V5

    public class SwaggerAddEnumDescriptions : IDocumentFilter
{
    public void Apply(OpenApiDocument swaggerDoc, DocumentFilterContext context)
    {
        // add enum descriptions to result models
        foreach (var property in swaggerDoc.Components.Schemas.Where(x => x.Value?.Enum?.Count > 0))
        {
            IList<IOpenApiAny> propertyEnums = property.Value.Enum;
            if (propertyEnums != null && propertyEnums.Count > 0)
            {
                property.Value.Description += DescribeEnum(propertyEnums, property.Key);
            }
        }

        // add enum descriptions to input parameters
        foreach (var pathItem in swaggerDoc.Paths.Values)
        {
            DescribeEnumParameters(pathItem.Operations, swaggerDoc);
        }
    }

    private void DescribeEnumParameters(IDictionary<OperationType, OpenApiOperation> operations, OpenApiDocument swaggerDoc)
    {
        if (operations != null)
        {
            foreach (var oper in operations)
            {
                foreach (var param in oper.Value.Parameters)
                {
                    var paramEnum = swaggerDoc.Components.Schemas.FirstOrDefault(x => x.Key == param.Name);
                    if (paramEnum.Value != null)
                    {
                        param.Description += DescribeEnum(paramEnum.Value.Enum, paramEnum.Key);
                    }
                }
            }
        }
    }

    private Type GetEnumTypeByName(string enumTypeName)
    {
        return AppDomain.CurrentDomain
            .GetAssemblies()
            .SelectMany(x => x.GetTypes())
            .FirstOrDefault(x => x.Name == enumTypeName);
    }

    private string DescribeEnum(IList<IOpenApiAny> enums, string proprtyTypeName)
    {
        List<string> enumDescriptions = new List<string>();
        var enumType = GetEnumTypeByName(proprtyTypeName);
        if (enumType == null)
            return null;

        foreach (OpenApiInteger enumOption in enums)
        {
            int enumInt = enumOption.Value;

            enumDescriptions.Add(string.Format("{0} = {1}", enumInt, Enum.GetName(enumType, enumInt)));
        }

        return string.Join(", ", enumDescriptions.ToArray());
    }
}

Answer 2

I just did this and it works fine!

Startup.cs

services.AddSwaggerGen(c => {
  c.DescribeAllEnumsAsStrings();
});

Model.cs

public enum ColumnType {
  DATE = 0
}

swagger.json

type: {
  enum: ["DATE"],
  type: "string"
}

I hope this helps you how it helped me!

Answer 3

write code inside Startup.cs

services.AddSwaggerGen(c => {
      c.DescribeAllEnumsAsStrings();
    });

Answer 4

ASP.NET Core 3.1

To generate enums as strings using Newtonsoft JSON you must explicitly add Newtonsoft support by adding AddSwaggerGenNewtonsoftSupport() as follows:

services.AddMvc()
    ...
    .AddNewtonsoftJson(opts =>
    {
        opts.SerializerSettings.Converters.Add(new StringEnumConverter());
    });


services.AddSwaggerGen(...);
services.AddSwaggerGenNewtonsoftSupport(); //

This is available via a new package, Swashbuckle.AspNetCore.Newtonsoft. It looks like everything else works fine without this package apart from enum converter support.

Answer 5

.Net Core 3.0

   using Newtonsoft.Json.Converters;

 services
    .AddMvc(options =>
    {
     options.EnableEndpointRouting = false;
     })
    .AddNewtonsoftJson(options => options.SerializerSettings.Converters.Add(new StringEnumConverter()))

Answer 6

From the docs:

httpConfiguration
    .EnableSwagger(c => 
        {
            c.SingleApiVersion("v1", "A title for your API");

            c.DescribeAllEnumsAsStrings(); // this will do the trick
        });

Also, if you want this behavior only on a particular type and property, use the StringEnumConverter:

public class Letter 
{
    [Required]
    public string Content {get; set;}

    [Required]
    [EnumDataType(typeof(Priority))]
    [JsonConverter(typeof(StringEnumConverter))]
    public Priority Priority {get; set;}
}