Generate routes and variants from OpenApi document

[javierbrea]

It is desirable to support generating routes and variants automatically from an OpenApi document. The routes ids could be assigned using the method and path (${method}-${path}). Variants could be created using the OpenApi responses and their examples (${statusCode}-${exampleId}). For defining other ids, the x-mocks-server-id property could be used in the OpenApi document, and maybe it would be interesting also to provide a hook allowing to transform the proposed ids into another custom format.

For creating the routes and variants, it could be done using different approaches:

Javascript library

A JavaScript library exporting methods for generating the routes. Collections should be added manually. For example, in a routes folder this library would be used as in:

const { createRoutes } = require("@mocks-server/plugin-open-api");

module.exports = [
  createRoutes({
    baseUrl: "/api"
    document:  {} // Open API document
  })
];

This would allow to load OpenAPI documents from files, or to perform a request to load it from a remote server, etc. (Caution: Asyncs are not supported when loading files for the moment. Maybe the core should accept also exporting async functions apart from plain arrays when loading routes in order to allow users to generate routes from async processes)

Plugin

A plugin receiving some options could be at charge of automatically creating the routes from files in the mocks folder, or from urls. Its configuration could look like:

{
   plugins: {
    openApi: {
      createRoutes: [ // Supports using n OpenApi documents
         {
            baseUrl: "/api",
            file: "openApi/openapi.json" // relative to files.path, or absolute
         },
         {
            baseUrl: "/api",
            url: "https://api.my-project.com/openapi.json" // relative to files.path, or absolute
         },
         {
            baseUrl: "/api",
            document: { } // Define OpenApi document here directly
         }
      ]
    }
  }
}

Both approaches are compatible and could be available at the same time, because the plugin could export the method for creating the routes while it uses it internally.