NSwag enum

https://github.com/RSuter/NJsonSchema/wiki/JsonSchemaGenerator#integer-vs-string-enumerations

Integer vs string enumerations

JSON Schema supports integer and string enumerations. In Json.NET, enums are serialized as integer by default. However you can mark a property with the JsonConverterAttribute so that it is serialized as string. NJsonSchema looks for these attributes and generates the enum JSON Schema respecting this attribute:

// Only this property is serialized as string
[JsonConverter(typeof(StringEnumConverter))]
public Gender Gender { get; set; }
 
// Always serialized as string
[JsonConverter(typeof(StringEnumConverter))]
public enum Gender
{
    ...
}

Also see Enums

https://stackoverflow.com/questions/36452468/swagger-ui-web-api-documentation-present-enums-as-strings

So I think I have a similar problem. I'm looking for swagger to generate enums along with the int -> string mapping. The API must accept the int. The swagger-ui matters less, what I really want is code generation with a "real" enum on the other side (android apps using retrofit in this case).

So from my research this ultimately seems to be a limit of the OpenAPI specification which Swagger uses. It's not possible to specify names and numbers for enums.

The best issue I've found to follow is https://github.com/OAI/OpenAPI-Specification/issues/681 which looks like a "maybe soon" but then Swagger would have to be updated, and in my case Swashbuckle as well.

For now my workaround has been to implement a document filter that looks for enums and populates the relevant description with the contents of the enum.

 GlobalConfiguration.Configuration
            .EnableSwagger(c =>
                {
                    c.DocumentFilter<SwaggerAddEnumDescriptions>();
 
                    //disable this
                    //c.DescribeAllEnumsAsStrings()

SwaggerAddEnumDescriptions.cs:

using System;
using System.Web.Http.Description;
using Swashbuckle.Swagger;
using System.Collections.Generic;
 
public class SwaggerAddEnumDescriptions : IDocumentFilter
{
    public void Apply(SwaggerDocument swaggerDoc, SchemaRegistry schemaRegistry, IApiExplorer apiExplorer)
    {
        // add enum descriptions to result models
        foreach (KeyValuePair<string, Schema> schemaDictionaryItem in swaggerDoc.definitions)
        {
            Schema schema = schemaDictionaryItem.Value;
            foreach (KeyValuePair<string, Schema> propertyDictionaryItem in schema.properties)
            {
                Schema property = propertyDictionaryItem.Value;
                IList<object> propertyEnums = property.@enum;
                if (propertyEnums != null && propertyEnums.Count > )
                {
                    property.description += DescribeEnum(propertyEnums);
                }
            }
        }
 
        // add enum descriptions to input parameters
        if (swaggerDoc.paths.Count > )
        {
            foreach (PathItem pathItem in swaggerDoc.paths.Values)
            {
                DescribeEnumParameters(pathItem.parameters);
 
                // head, patch, options, delete left out
                List<Operation> possibleParameterisedOperations = new List<Operation> { pathItem.get, pathItem.post, pathItem.put };
                possibleParameterisedOperations.FindAll(x => x != null).ForEach(x => DescribeEnumParameters(x.parameters));
            }
        }
    }
 
    private void DescribeEnumParameters(IList<Parameter> parameters)
    {
        if (parameters != null)
        {
            foreach (Parameter param in parameters)
            {
                IList<object> paramEnums = param.@enum;
                if (paramEnums != null && paramEnums.Count > )
                {
                    param.description += DescribeEnum(paramEnums);
                }
            }
        }
    }
 
    private string DescribeEnum(IList<object> enums)
    {
        List<string> enumDescriptions = new List<string>();
        foreach (object enumOption in enums)
        {
            enumDescriptions.Add(string.Format("{0} = {1}", (int)enumOption, Enum.GetName(enumOption.GetType(), enumOption)));
        }
        return string.Join(", ", enumDescriptions.ToArray());
    }
 
}

This results in something like the following on your swagger-ui so at least you can "see what you're doing":