Swagger with vendor extension at API/controller level

Question

I got an Asp.Net web api project with some controllers, enabled swagger doc with swagger-Net. I have been searching for how to enable vendor extensions or custom swagger doc fields which I can set for each API level. I'm successful at settting vendor extension at swagger doc level/swaggerDoc.Info level. But I can't go further to set them at API level. Any help would be extremely grateful!

I tried adding vendor extensions to swaggerDoc.Info and it works great. But I don't know how to add vendor extension to API level (PathItem) which can be set or ediited for individual APIs. Basically I want to enable setting of a vendor extension x-dev at API level.

[HttpGet]
[x-dev("Myself")]
public async Task<User> GetAllUsers(){
.....................
}

Answer 1

Okay, I found a way.

Suppose I want to add a vendor extension "Squad" to each operation,

first create an Attribute which will be used whenever we want to attribute a particular squad to an operation.

public class SquadAttribute : Attribute

{

    public string squadName;

    public SquadAttribute(string squadName)

    {

       this.squadName = squadName;

    }

 }

then in SwaggerConfig.cs add operation filter which will add our attribute as a vendor extension to operations.

public class SquadOperationFilter : IOperationFilter
    {
        public void Apply(Operation operation, SchemaRegistry schemaRegistry, ApiDescription apiDescription)
        {
            var sq = apiDescription.GetControllerAndActionAttributes<SquadAttribute>().FirstOrDefault();
            if (sq != null)
            {
                operation.vendorExtensions.Add("x-SquadName", sq.squadName);
                
            }
        }
    }

finally in swagger.config, Apply operationfilter.

c.OperationFilter<SquadOperationFilter>();

Now you can add squad attribute for any openApi operation like this :

[HttpGet]

["Settings"]

[Squad("DevSquad")]

public async Task GetAllSettings()

{

...............................

...............................

}