Support multiple distinct UIs

[fozziethebeat]

Prerequisites

• [X] I have written a descriptive issue title
• [X] I have searched existing issues to ensure the feature has not already been requested

🚀 Feature Proposal

With ChatGPT plugins depending on OpenAPI specifications, it would be really helpful if there's a simplified way to create at least two distinct OpenAPI specifications and Swagger UI's. Each version would have to live under distinct URL routes. They would both consume the same underlying swaggerObject but would likely have different transformSpecification functions to selectively reveal or hide different routes.

Ideally this is done by registering the swagger ui plugin multiple times and configuring them appropriately.

Right now this doesn't work because the plugin does some decorations that clash on the second registration.

Motivation

This would make it trivial to run and manage a single server that has an API service that's suitable for OpenAI plugins with a subset of routes supported and a wider set of API routes that are available for other clients, such as a web app.

Example

An example setup could be:

  await fastify.register(require("@fastify/swagger-ui"), {
    routePrefix: "/internal-documentation",
    uiConfig: {
      docExpansion: "full",
      deepLinking: false,
    },
    uiHooks: {
      onRequest: function (request, reply, next) {
        next();
      },
      preHandler: function (request, reply, next) {
        next();
      },
    },
    staticCSP: true,
    transformStaticCSP: (header) => header,
    transformSpecification: internalAPITransformation,
    transformSpecificationClone: true,
  });
  await fastify.register(require("@fastify/swagger-ui"), {
    routePrefix: "/external-documentation",
    uiConfig: {
      docExpansion: "full",
      deepLinking: false,
    },
    uiHooks: {
      onRequest: function (request, reply, next) {
        next();
      },
      preHandler: function (request, reply, next) {
        next();
      },
    },
    staticCSP: true,
    transformStaticCSP: (header) => header,
    transformSpecification: externalAPITransformation,
    transformSpecificationClone: true,
  });

[mcollina]

What error are you getting when running the above? This should be feasible to achieve.

[fozziethebeat]

I'm getting the following error from Fastify:

[App] FastifyError [Error]: The decorator 'swaggerCSP' has already been added!
[App]     at decorate (/Users/fozziethebeat/devel/durable/AI-API/node_modules/fastify/li
b/decorate.js:23:11)
[App]     at Object.decorateFastify [as decorate] (/Users/fozziethebeat/devel/durable/AI-API/node_modules/fastify/lib/decorate.js:67:3)
[App]     at fastifySwaggerUi (/Users/fozziethebeat/devel/durable/AI-API/node_modules/@fastify/swagger-ui/index.js:7:11)
[App]     at Plugin.exec (/Users/fozziethebeat/devel/durable/AI-API/node_modules/avvio/p
lugin.js:130:19)
[App]     at Boot.loadPlugin (/Users/fozziethebeat/devel/durable/AI-API/node_modules/avvio/plugin.js:272:10)
[App]     at process.processTicksAndRejections (node:internal/process/task_queues:82:21)
 {
[App]   code: 'FST_ERR_DEC_ALREADY_PRESENT',
[App]   statusCode: 500
[App] }

I'm guessing it's as simple as making that csp object more uniquely named each time the plugin is registered.

[Eomm]

You need to create two encapsulated contexts. Here is an example with another plugin - but the code would be the same: https://stackoverflow.com/questions/75938106/is-there-any-way-to-configure-fastify-caching-per-route/

[fozziethebeat]

Well, something new i just learned about Fastify. That absolutely solved the problem with just a few line changes. Thank you!

[ThomasKoscheck]

@fozziethebeat I have the same problem, can you share how you exactly did it?

[fozziethebeat]

I sadly have forgotten what I did here