express-openapi: allow to registered errorMiddleware when exposeApiDo…

…cs is falsy (fixes #435) (#475)

packages/express-openapi/index.ts

@@ -81,28 +81,30 @@ export function initialize(args: ExpressOpenAPIArgs): OpenAPIFramework {
 
   framework.initialize({
     visitApi: ctx => {
-      if (exposeApiDocs) {
+      if (exposeApiDocs || errorMiddleware) {
         const basePaths = [];
-        const apiDoc = ctx.getApiDoc();
         basePaths.push(...ctx.basePaths.map(toExpressBasePath));
 
-        // Swagger UI support
         for (const basePath of basePaths) {
-          app.get(basePath + docsPath, (req, res, next) => {
-            // @ts-ignore
-            req.apiDoc = ctx.getApiDoc();
-            // @ts-ignore
-            if (req.apiDoc.swagger) {
+          // Swagger UI support
+          if (exposeApiDocs) {
+            app.get(basePath + docsPath, (req, res, next) => {
               // @ts-ignore
-              req.apiDoc.host = req.headers.host;
-              const apiBasePath = req.baseUrl + basePath;
+              req.apiDoc = ctx.getApiDoc();
               // @ts-ignore
-              req.apiDoc.basePath =
-                apiBasePath.length === 0 ? '/' : apiBasePath;
-            }
-            securityFilter(req, res, next);
-          });
+              if (req.apiDoc.swagger) {
+                // @ts-ignore
+                req.apiDoc.host = req.headers.host;
+                const apiBasePath = req.baseUrl + basePath;
+                // @ts-ignore
+                req.apiDoc.basePath =
+                  apiBasePath.length === 0 ? '/' : apiBasePath;
+              }
+              securityFilter(req, res, next);
+            });
+          }
 
+          // register custom error middleware to api's basePath
           if (errorMiddleware) {
             app.use(basePath, errorMiddleware);
           }

packages/express-openapi/test/sample-projects/with-errorMiddleware-and-exposeApiDocs-set-to-false/api-doc.js

@@ -0,0 +1,22 @@
+// args.apiDoc needs to be a js object.  This file could be a json file, but we can't add
+// comments in json files.
+module.exports = {
+  swagger: '2.0',
+
+  // all routes will now have /v3 prefixed.
+  basePath: '/v3',
+
+  info: {
+    title: 'express-openapi sample project',
+    version: '3.0.0'
+  },
+
+  definitions: {
+    Foo: {
+      type: 'string'
+    }
+  },
+
+  // paths are derived from args.routes.  These are filled in by fs-routes.
+  paths: {}
+};

packages/express-openapi/test/sample-projects/with-errorMiddleware-and-exposeApiDocs-set-to-false/api-routes/foo.js

@@ -0,0 +1,16 @@
+module.exports = {
+  get: function(req, res, next) {
+    next(new Error('hello from /v3/foo'));
+  }
+};
+
+module.exports.get.apiDoc = {
+  description: 'Get foo.',
+  operationId: 'getFoo',
+  parameters: [],
+  responses: {
+    200: {
+      description: 'testing error handler'
+    }
+  }
+};

packages/express-openapi/test/sample-projects/with-errorMiddleware-and-exposeApiDocs-set-to-false/app.js

@@ -0,0 +1,34 @@
+var app = require('express')();
+var bodyParser = require('body-parser');
+// normally you'd just do require('express-openapi'), but this is for test purposes.
+var openapi = require('../../../');
+var path = require('path');
+var cors = require('cors');
+
+app.use(cors());
+app.use(bodyParser.json());
+
+app.get('/foo', function(req, res, next) {
+  next(new Error('hello from /foo'));
+});
+
+openapi.initialize({
+  apiDoc: require('./api-doc.js'),
+  app: app,
+  paths: path.resolve(__dirname, 'api-routes'),
+  exposeApiDocs: false,
+  errorMiddleware: function(err, req, res, next) {
+    res.status(200).json(err.message);
+  }
+});
+
+app.use(function(err, req, res, next) {
+  res.status(200).json(err.message);
+});
+
+module.exports = app;
+
+var port = parseInt(process.argv[2], 10);
+if (port) {
+  app.listen(port);
+}

packages/express-openapi/test/sample-projects/with-errorMiddleware-and-exposeApiDocs-set-to-false/spec.js

@@ -0,0 +1,23 @@
+var app;
+var expect = require('chai').expect;
+var request = require('supertest');
+
+before(function() {
+  app = require('./app.js');
+});
+
+describe('when an error occurs in the basePath', function() {
+  it('should use the API error middleware', function(done) {
+    request(app)
+      .get('/v3/foo')
+      .expect(200, '"hello from /v3/foo"', done);
+  });
+});
+
+describe('when an error occurs outside the basePath', function() {
+  it('should not use the API error middleware', function(done) {
+    request(app)
+      .get('/foo')
+      .expect(200, '"hello from /foo"', done);
+  });
+});