feat(rest): push route(verb, path, spec, fn) down to RestServer

Move the implementation of 4-arg version of "route` method from
RestApplication to RestServer, simplify RestApplication's "route"
to delegate the implementation to RestServer.

Author: bajtos

packages/rest/src/rest.application.ts

@@ -3,22 +3,21 @@
 // This file is licensed under the MIT License.
 // License text available at https://opensource.org/licenses/MIT
 
-import {Application, ApplicationConfig, Server} from '@loopback/core';
-import {RestComponent} from './rest.component';
-import {SequenceHandler, SequenceFunction} from './sequence';
 import {Binding, Constructor} from '@loopback/context';
+import {Application, ApplicationConfig, Server} from '@loopback/core';
+import {OpenApiSpec, OperationObject} from '@loopback/openapi-v3-types';
+import {PathParams} from 'express-serve-static-core';
+import {ServeStaticOptions} from 'serve-static';
 import {format} from 'util';
 import {RestBindings} from './keys';
-import {RestServer, HttpRequestListener, HttpServerLike} from './rest.server';
+import {RestComponent} from './rest.component';
+import {HttpRequestListener, HttpServerLike, RestServer} from './rest.server';
 import {
-  RouteEntry,
   ControllerClass,
   ControllerFactory,
-  Route,
+  RouteEntry,
 } from './router/routing-table';
-import {OperationObject, OpenApiSpec} from '@loopback/openapi-v3-types';
-import {ServeStaticOptions} from 'serve-static';
-import {PathParams} from 'express-serve-static-core';
+import {SequenceFunction, SequenceHandler} from './sequence';
 
 export const ERR_NO_MULTI_SERVER = format(
   'RestApplication does not support multiple servers!',
@@ -127,6 +126,29 @@ export class RestApplication extends Application implements HttpServerLike {
     methodName: string,
   ): Binding;
 
+  /**
+   * Register a new route invoking a handler function.
+   *
+   * ```ts
+   * function greet(name: string) {
+   *  return `hello ${name}`;
+   * }
+   * app.route('get', '/', operationSpec, greet);
+   * ```
+   *
+   * @param verb HTTP verb of the endpoint
+   * @param path URL path of the endpoint
+   * @param spec The OpenAPI spec describing the endpoint (operation)
+   * @param handler The function to invoke with the request parameters
+   * described in the spec.
+   */
+  route(
+    verb: string,
+    path: string,
+    spec: OperationObject,
+    handler: Function,
+  ): Binding;
+
   /**
    * Register a new route.
    *
@@ -172,7 +194,10 @@ export class RestApplication extends Application implements HttpServerLike {
       return server.route(routeOrVerb);
     } else if (arguments.length === 4) {
       return server.route(
-        new Route(routeOrVerb, path!, spec!, controllerCtorOrHandler!),
+        routeOrVerb,
+        path!,
+        spec!,
+        controllerCtorOrHandler as Function,
       );
     } else {
       return server.route(

packages/rest/src/rest.server.ts

@@ -520,7 +520,30 @@ export class RestServer extends Context implements Server, HttpServerLike {
   ): Binding;
 
   /**
-   * Register a new route.
+   * Register a new route invoking a handler function.
+   *
+   * ```ts
+   * function greet(name: string) {
+   *  return `hello ${name}`;
+   * }
+   * app.route('get', '/', operationSpec, greet);
+   * ```
+   *
+   * @param verb HTTP verb of the endpoint
+   * @param path URL path of the endpoint
+   * @param spec The OpenAPI spec describing the endpoint (operation)
+   * @param handler The function to invoke with the request parameters
+   * described in the spec.
+   */
+  route(
+    verb: string,
+    path: string,
+    spec: OperationObject,
+    handler: Function,
+  ): Binding;
+
+  /**
+   * Register a new generic route.
    *
    * ```ts
    * function greet(name: string) {
@@ -534,12 +557,12 @@ export class RestServer extends Context implements Server, HttpServerLike {
    */
   route(route: RouteEntry): Binding;
 
-  route<I>(
+  route<T>(
     routeOrVerb: RouteEntry | string,
     path?: string,
     spec?: OperationObject,
-    controllerCtor?: ControllerClass<I>,
-    controllerFactory?: ControllerFactory<I>,
+    controllerCtorOrHandler?: ControllerClass<T> | Function,
+    controllerFactory?: ControllerFactory<T>,
     methodName?: string,
   ): Binding {
     if (typeof routeOrVerb === 'object') {
@@ -563,7 +586,18 @@ export class RestServer extends Context implements Server, HttpServerLike {
       });
     }
 
-    if (!controllerCtor) {
+    if (arguments.length === 4) {
+      if (!controllerCtorOrHandler) {
+        throw new AssertionError({
+          message: 'handler function is required for a handler-based route',
+        });
+      }
+      return this.route(
+        new Route(routeOrVerb, path, spec, controllerCtorOrHandler as Function),
+      );
+    }
+
+    if (!controllerCtorOrHandler) {
       throw new AssertionError({
         message: 'controller is required for a controller-based route',
       });
@@ -580,7 +614,7 @@ export class RestServer extends Context implements Server, HttpServerLike {
         routeOrVerb,
         path,
         spec,
-        controllerCtor,
+        controllerCtorOrHandler as ControllerClass<T>,
         controllerFactory,
         methodName,
       ),

packages/rest/test/acceptance/routing/routing.acceptance.ts

@@ -6,7 +6,6 @@
 import {
   Request,
   Response,
-  Route,
   RestBindings,
   RestServer,
   RestComponent,
@@ -408,8 +407,7 @@ describe('Routing', () => {
       return `hello ${name}`;
     }
 
-    const route = new Route('get', '/greet', routeSpec, greet);
-    server.route(route);
+    server.route('get', '/greet', routeSpec, greet);
 
     const client = whenIMakeRequestTo(server);
     await client.get('/greet?name=world').expect(200, 'hello world');
@@ -609,8 +607,7 @@ describe('Routing', () => {
         return `hello ${name}`;
       }
 
-      const route = new Route('get', '/greet', routeSpec, greet);
-      app.route(route);
+      app.route('get', '/greet', routeSpec, greet);
 
       await whenIMakeRequestTo(app)
         .get('/greet?name=world')

packages/rest/test/integration/rest.server.integration.ts

@@ -12,7 +12,7 @@ import {
   httpsGetAsync,
   givenHttpServerConfig,
 } from '@loopback/testlab';
-import {Route, RestBindings, RestServer, RestComponent} from '../..';
+import {RestBindings, RestServer, RestComponent} from '../..';
 import {IncomingMessage, ServerResponse} from 'http';
 import * as yaml from 'js-yaml';
 import * as path from 'path';
@@ -238,7 +238,7 @@ describe('RestServer (integration)', () => {
         },
       },
     };
-    server.route(new Route('get', '/greet', greetSpec, function greet() {}));
+    server.route('get', '/greet', greetSpec, function greet() {});
 
     const response = await createClientForHandler(server.requestHandler).get(
       '/openapi.json',
@@ -330,7 +330,7 @@ describe('RestServer (integration)', () => {
         },
       },
     };
-    server.route(new Route('get', '/greet', greetSpec, function greet() {}));
+    server.route('get', '/greet', greetSpec, function greet() {});
 
     const response = await createClientForHandler(server.requestHandler).get(
       '/openapi.yaml',
@@ -372,7 +372,7 @@ paths:
         },
       },
     };
-    server.route(new Route('get', '/greet', greetSpec, function greet() {}));
+    server.route('get', '/greet', greetSpec, function greet() {});
 
     const response = await createClientForHandler(server.requestHandler).get(
       '/explorer',

packages/rest/test/unit/rest.server/rest.server.open-api-spec.unit.ts

@@ -7,7 +7,6 @@ import {expect, validateApiSpec} from '@loopback/testlab';
 import {Application} from '@loopback/core';
 import {
   RestServer,
-  Route,
   RestComponent,
   createControllerFactoryForClass,
 } from '../../..';
@@ -51,9 +50,7 @@ describe('RestServer.getApiSpec()', () => {
 
   it('binds a route via app.route(route)', () => {
     function greet() {}
-    const binding = server.route(
-      new Route('get', '/greet', {responses: {}}, greet),
-    );
+    const binding = server.route('get', '/greet', {responses: {}}, greet);
     expect(binding.key).to.eql('routes.get %2Fgreet');
     expect(binding.tagNames).containEql('route');
   });
@@ -77,7 +74,7 @@ describe('RestServer.getApiSpec()', () => {
 
   it('returns routes registered via app.route(route)', () => {
     function greet() {}
-    server.route(new Route('get', '/greet', {responses: {}}, greet));
+    server.route('get', '/greet', {responses: {}}, greet);
 
     const spec = server.getApiSpec();
     expect(spec.paths).to.eql({
@@ -195,7 +192,7 @@ describe('RestServer.getApiSpec()', () => {
     );
 
     function greet() {}
-    server.route(new Route('get', '/greet', {responses: {}}, greet));
+    server.route('get', '/greet', {responses: {}}, greet);
 
     const spec = server.getApiSpec();
     expect(spec.paths).to.eql({