How to customize Swagger endpoint url?

Question

I have multiple web api projects (microservices), and I want to expose them using only one swagger-ui link. I'll call each web api project EndpointA and EndpointB for the sake of this post.

I've created a swagger-ui project, and I've added each endpoint to this project.

My swagger-ui project Startup.cs

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    app.UseSwaggerUI(c => {
        c.SwaggerEndpoint("/EndpointA/swagger/v1/swagger.json", "EndpointA");
        c.SwaggerEndpoint("/EndpointB/swagger/v1/swagger.json", "EndpointB");
    });
}

My endpoints A/B Startup.cs

public void ConfigureServices(IServiceCollection services)
{
    services.AddSwaggerGen(c =>
    {
        c.SwaggerDoc("v1", new Info
        {
            Version = "v1",
            Title = "EndpointA", // or "EndpointB",
        });
    });
}

---

My problem is that each of the swagger.json files doesn't contains the endpoint prefix. Instead of being /EndpointA/Controller/Action, the paths are /Controller/Action, which are not valid.

---

I have tried to set a custom url prefix in my swagger ui project like this c.RoutePrefix = "EndpointA";. It works for my EndpointA, but I can only set one for all endpoints so EndpointB won't works.

I also tried to set a prefix directly in each endpoint using SwaggerGen, but I don't know how / if it's possible.

Answer 1

I ended up using the UsePathBaseExtensions.UsePathBase(IApplicationBuilder, PathString) Method to register a base path to my api.

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    app.UsePathBase(new PathString("/EndpointA"));
    app.UseMvc();
}

---

An alternate solution would have been to use the swagger base path document filter like so:

public void ConfigureServices(IServiceCollection services)
{
     services.AddSwaggerGen(c =>
     {
         c.DocumentFilter<BasePathFilter>();
     });
 }

And the filter:

public class BasePathFilter: IDocumentFilter
{
    public void Apply(SwaggerDocument swaggerDoc, DocumentFilterContext context)
    {
        swaggerDoc.BasePath = "/EndpointA";
    }
}