Is it possible to define a common route parameter that can be set at the top of document, and if used it is injected in all the required routes?

We have a set of routes that all share a common route value i.e. ~/user/{userId:guid}/....

Is it possible to setup the swagger document in such a way that there is a global user id field that when set applies its value to each route that has a /{userId:guid}/ segment? So that when you are using the UI you don't have to manually copy the user id into each operation?

Is it possible to define a common route parameter that can be set at the top of document, and if used it is injected in all the required routes?

We have a set of routes that all share a common route value i.e. ~/user/{userId:guid}/....

Is it possible to setup the swagger document in such a way that there is a global user id field that when set applies its value to each route that has a /{userId:guid}/ segment? So that when you are using the UI you don't have to manually copy the user id into each operation?

• c#
• swagger
• swagger-ui
• nswag

1 Answer 1

Yes, you can use IOperationFilter in Swagger to add a global route parameter. I’ve done something similar for API keys by setting them as required headers, and you can use the same approach for route parameters.

using Microsoft.OpenApi.Models;
using Swashbuckle.AspNetCore.SwaggerGen;

namespace ApiKeyImplementation.Helpers
{
    public class CustomHeaderSwaggerAttribute : IOperationFilter
    {
        public void Apply(OpenApiOperation operation, OperationFilterContext context)
        {
            if (operation.Parameters == null)
                operation.Parameters = new List<OpenApiParameter>();
            operation.Parameters.Add(new OpenApiParameter
            {
                Name = VarHelper.KeyTypes.ApiKey.ToString(), //Add Key Name
                In = ParameterLocation.Header, //Set Location
                Required = true,
                Description = "Add description if necessary",
                Schema = new OpenApiSchema
                {
                    Type = "string"
                }
            });
            //If your application requires AppId as part of authentication
            operation.Parameters.Add(new OpenApiParameter
            {
                Name = VarHelper.KeyTypes.AppId.ToString(),
                In = ParameterLocation.Header,
                Required = true,
                Schema = new OpenApiSchema
                {
                    Type = "string"
                }
            });
        }
    }
}

In your case, your will need to change the

In = ParameterLocation.Header => In = ParameterLocation.Path

Then register the filter in your program.cs

builder.Services.AddSwaggerGen(config =>
{
// Add Operation filter for header
config.OperationFilter<CustomHeaderSwaggerAttribute>();
});