Fix issue #78: Separate OpenAPI specs for multiple middleware instances

- Store owned routes directly on middleware instance using Set
- Filter routes to exclude those owned by other OpenAPI middlewares
- Ensures each middleware only includes its own routes while preserving sub-router compatibility

Author: henry232323

index.js

@@ -39,7 +39,7 @@ module.exports = function ExpressOpenApi (_routePrefix, _doc, _opts) {
   // Where the magic happens
   const middleware = function OpenApiMiddleware (req, res, next) {
     if (isFirstRequest) {
-      middleware.document = generateDocument(middleware.document, req.app._router || req.app.router, opts.basePath)
+      middleware.document = generateDocument(middleware.document, req.app._router || req.app.router, opts.basePath, middleware)
       isFirstRequest = false
     }
 
@@ -48,8 +48,8 @@ module.exports = function ExpressOpenApi (_routePrefix, _doc, _opts) {
 
   // Expose the current document and prefix
   middleware.routePrefix = routePrefix
-  middleware.document = generateDocument(doc, undefined, opts.basePath)
-  middleware.generateDocument = generateDocument
+  middleware.document = generateDocument(doc, undefined, opts.basePath, middleware)
+  middleware.generateDocument = (doc, router, basePath) => generateDocument(doc, router, basePath, middleware)
   middleware.options = opts
 
   // Add a path schema to the document
@@ -59,6 +59,7 @@ module.exports = function ExpressOpenApi (_routePrefix, _doc, _opts) {
     }
 
     setSchema(schemaMiddleware, schema)
+    schemaMiddleware._ownerMiddleware = middleware
     return schemaMiddleware
   }
 
@@ -73,6 +74,7 @@ module.exports = function ExpressOpenApi (_routePrefix, _doc, _opts) {
     }
 
     setSchema(validSchemaMiddleware, schema)
+    validSchemaMiddleware._ownerMiddleware = middleware
     return validSchemaMiddleware
   }
 
@@ -131,13 +133,13 @@ module.exports = function ExpressOpenApi (_routePrefix, _doc, _opts) {
 
   // OpenAPI document as json
   router.get(`${routePrefix}.json`, (req, res) => {
-    middleware.document = generateDocument(middleware.document, req.app._router || req.app.router, opts.basePath)
+    middleware.document = generateDocument(middleware.document, req.app._router || req.app.router, opts.basePath, middleware)
     res.json(middleware.document)
   })
 
   // OpenAPI document as yaml
   router.get([`${routePrefix}.yaml`, `${routePrefix}.yml`], (req, res) => {
-    const jsonSpec = generateDocument(middleware.document, req.app._router || req.app.router, opts.basePath)
+    const jsonSpec = generateDocument(middleware.document, req.app._router || req.app.router, opts.basePath, middleware)
     const yamlSpec = YAML.stringify(jsonSpec)
 
     res.type('yaml')
@@ -146,7 +148,7 @@ module.exports = function ExpressOpenApi (_routePrefix, _doc, _opts) {
 
   router.get(`${routePrefix}/components/:type/:name.json`, (req, res, next) => {
     const { type, name } = req.params
-    middleware.document = generateDocument(middleware.document, req.app._router || req.app.router, opts.basePath)
+    middleware.document = generateDocument(middleware.document, req.app._router || req.app.router, opts.basePath, middleware)
 
     // No component by that identifer
     if (!middleware.document.components[type] || !middleware.document.components[type][name]) {
@@ -159,7 +161,7 @@ module.exports = function ExpressOpenApi (_routePrefix, _doc, _opts) {
 
   // Validate full open api document
   router.get(`${routePrefix}/validate`, (req, res) => {
-    middleware.document = generateDocument(middleware.document, req.app._router || req.app.router, opts.basePath)
+    middleware.document = generateDocument(middleware.document, req.app._router || req.app.router, opts.basePath, middleware)
     SwaggerParser.validate(middleware.document, (err, api) => {
       if (err) {
         return res.json({

lib/generate-doc.js

@@ -3,7 +3,7 @@ const pathToRegexp = require('path-to-regexp')
 const minimumViableDocument = require('./minimum-doc')
 const { get: getSchema, set: setSchema } = require('./layer-schema')
 
-module.exports = function generateDocument (baseDocument, router, basePath) {
+module.exports = function generateDocument (baseDocument, router, basePath, ownerMiddleware) {
   // Merge document with select minimum defaults
   const doc = Object.assign({
     openapi: minimumViableDocument.openapi
@@ -23,6 +23,11 @@ module.exports = function generateDocument (baseDocument, router, basePath) {
         return
       }
 
+      // If ownerMiddleware is provided, only exclude routes owned by other OpenAPI middlewares
+      if (ownerMiddleware && layer.handle._ownerMiddleware && layer.handle._ownerMiddleware !== ownerMiddleware) {
+        return
+      }
+
       const operation = Object.assign({}, schema)
 
       // Add route params to schema