@loopback/docs/site/apidocs/rest.restserver.md

Documentation for LoopBack 4

---
lang: en
title: 'API docs: rest.restserver'
keywords: LoopBack 4.0, LoopBack 4
sidebar: lb4_sidebar
permalink: /doc/en/lb4/apidocs.rest.restserver.html
---

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[Home](./index.md) &gt; [@loopback/rest](./rest.md) &gt; [RestServer](./rest.restserver.md)

## RestServer class

A REST API server for use with Loopback. Add this server to your application by importing the RestComponent.

<b>Signature:</b>

```typescript
export declare class RestServer extends Context implements Server, HttpServerLike 
```

## Constructors

|  Constructor | Modifiers | Description |
|  --- | --- | --- |
|  [(constructor)(app, config)](./rest.restserver.(constructor).md) |  | Creates an instance of RestServer. |

## Properties

|  Property | Modifiers | Type | Description |
|  --- | --- | --- | --- |
|  [\_expressApp](./rest.restserver._expressapp.md) |  | <code>express.Application</code> |  |
|  [\_httpHandler](./rest.restserver._httphandler.md) |  | <code>HttpHandler</code> |  |
|  [\_httpServer](./rest.restserver._httpserver.md) |  | <code>HttpServer &#124; undefined</code> |  |
|  [\_requestHandler](./rest.restserver._requesthandler.md) |  | <code>HttpRequestListener</code> | Handle incoming HTTP(S) request by invoking the corresponding Controller method via the configured Sequence. |
|  [config](./rest.restserver.config.md) |  | <code>RestServerResolvedConfig</code> |  |
|  [httpHandler](./rest.restserver.httphandler.md) |  | <code>HttpHandler</code> |  |
|  [listening](./rest.restserver.listening.md) |  | <code>boolean</code> |  |
|  [requestHandler](./rest.restserver.requesthandler.md) |  | <code>HttpRequestListener</code> |  |
|  [rootUrl](./rest.restserver.rooturl.md) |  | <code>string &#124; undefined</code> | The root url for the server without the basePath. For example, the value will be 'http://localhost:3000' regardless of the <code>basePath</code>. |
|  [url](./rest.restserver.url.md) |  | <code>string &#124; undefined</code> | The base url for the server, including the basePath if set. For example, the value will be 'http://localhost:3000/api' if <code>basePath</code> is set to '/api'. |

## Methods

|  Method | Modifiers | Description |
|  --- | --- | --- |
|  [\_applyExpressSettings()](./rest.restserver._applyexpresssettings.md) |  | Apply express settings. |
|  [\_handleHttpRequest(request, response)](./rest.restserver._handlehttprequest.md) |  |  |
|  [\_onUnhandledError(req, res, err)](./rest.restserver._onunhandlederror.md) |  |  |
|  [\_setupHandlerIfNeeded()](./rest.restserver._setuphandlerifneeded.md) |  |  |
|  [\_setupOpenApiSpecEndpoints()](./rest.restserver._setupopenapispecendpoints.md) |  | Mount /openapi.json, /openapi.yaml for specs and /swagger-ui, /explorer to redirect to externally hosted API explorer |
|  [\_setupRequestHandlerIfNeeded()](./rest.restserver._setuprequesthandlerifneeded.md) |  |  |
|  [api(spec)](./rest.restserver.api.md) |  | Set the OpenAPI specification that defines the REST API schema for this server. All routes, parameter definitions and return types will be defined in this way.<!-- -->Note that this will override any routes defined via decorators at the controller level (this function takes precedent). |
|  [basePath(path)](./rest.restserver.basepath.md) |  | Configure the <code>basePath</code> for the rest server |
|  [bodyParser(bodyParserClass, address)](./rest.restserver.bodyparser.md) |  | Bind a body parser to the server context |
|  [controller(controllerCtor)](./rest.restserver.controller.md) |  | Register a controller class with this server. |
|  [getApiSpec()](./rest.restserver.getapispec.md) |  | Get the OpenAPI specification describing the REST API provided by this application.<!-- -->This method merges operations (HTTP endpoints) from the following sources: - <code>app.api(spec)</code> - <code>app.controller(MyController)</code> - <code>app.route(route)</code> - <code>app.route('get', '/greet', operationSpec, MyController, 'greet')</code> |
|  [handler(handlerFn)](./rest.restserver.handler.md) |  | Configure a custom sequence function for handling incoming requests. |
|  [mountExpressRouter(basePath, router, spec)](./rest.restserver.mountexpressrouter.md) |  | Mount an Express router to expose additional REST endpoints handled via legacy Express-based stack. |
|  [redirect(fromPath, toPathOrUrl, statusCode)](./rest.restserver.redirect.md) |  | Register a route redirecting callers to a different URL. |
|  [route(verb, path, spec, controllerCtor, controllerFactory, methodName)](./rest.restserver.route.md) |  | Register a new Controller-based route. |
|  [route(verb, path, spec, handler)](./rest.restserver.route_1.md) |  | Register a new route invoking a handler function. |
|  [route(route)](./rest.restserver.route_2.md) |  | Register a new generic route. |
|  [sequence(value)](./rest.restserver.sequence.md) |  | Configure a custom sequence class for handling incoming requests. |
|  [start()](./rest.restserver.start.md) |  | Start this REST API's HTTP/HTTPS server. |
|  [static(path, rootDir, options)](./rest.restserver.static.md) |  | Mount static assets to the REST server. See https://expressjs.com/en/4x/api.html\#express.static |
|  [stop()](./rest.restserver.stop.md) |  | Stop this REST API's HTTP/HTTPS server. |

## Example


```ts
const app = new MyApplication();
app.component(RestComponent);

```
To add additional instances of RestServer to your application, use the `.server` function:

```ts
app.server(RestServer, 'nameOfYourServer');

```
By default, one instance of RestServer will be created when the RestComponent is bootstrapped. This instance can be retrieved with `app.getServer(RestServer)`<!-- -->, or by calling `app.get('servers.RestServer')` Note that retrieving other instances of RestServer must be done using the server's name:

```ts
const server = await app.getServer('foo')
// OR
const server = await app.get('servers.foo');

```