# Controllers

Controllers are responsible for handling incoming requests and returning responses to the client.

A controller is here to handle a specific request for a given HTTP verb and Route. The routing service is responsible for managing and dispatching request to the right Controller.

In order to create a basic controller, we use classes and decorators. Decorators associate classes with required metadata and enable Ts.ED to create a routing map.

# Routing

# Usage

In the following example we'll use the decorator which is required to define a basic controller. We'll specify a path for the controller which will be used by the routing mechanism to create your routes.

import {Controller, Get} from "@tsed/common";

@Controller("/calendars")
export class CalendarCtrl {
  @Get()
  findAll(): string {
    return "This action returns all calendars";
  }
}
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The decorator before the findAll() method tells Ts.ED to create an endpoint for this particular route path and map every corresponding request to this handler. Since we've declared a prefix for every route (/calendars), Ts.ED will map every GET /calendars request to this method.

Ts.ED provides a decorator for each HTTP verb which can be use to handle a request:

# Configuration

You can add your controller by adding glob pattern on mount ServerSettings attributes or by importing manually your controller. Here an example:

import {ServerLoader, ServerSettings} from "@tsed/common";
import {CalendarCtrl} from "./controllers/CalendarCtrl";

@ServerSettings({
  mount: {
    "/rest": `./controllers/*.ts`, // using componentScan
    // Using manual import
    "/manual": [
      CalendarCtrl
    ]
  }
})
export class Server extends ServerLoader {
}
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# Create multiple versions of your API

As you have seen in the previous example, the mount attribute is an object that let you provide the global endpoint for all your controllers under the controllers folder.

You can add more configurations to mount different endpoints associated to a folder. Here is another configuration example:

import {ServerLoader, ServerSettings} from "@tsed/common";

@ServerSettings({
  mount: {
    "/rest/v0": "./controllers/v0/**/*.ts",
    "/rest/v1": "./controllers/v1/**/*.ts"
  }
})
export class Server extends ServerLoader {
}
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# Async and Promise

Ts.ED works well with Promise and async function. Every async function has to return a Promise. This means that you can return a deferred value that Ts.ED will be able to resolve by itself.

Let's see an example of this:

import {Controller, Get, PathParams} from "@tsed/common";

interface Calendar {
  id: string;
  name: string;
}

@Controller("/calendars")
export class CalendarCtrl {
  @Get("/:id")
  async get(
    @PathParams("id") id: string
  ): Promise<Calendar> {

    return {
      id,
      name: "test"
    };
  }
}
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# Observable/Stream/Buffer

Also, Ts.ED support function that return Observable, Stream or Buffer.

import {Controller, Get} from "@tsed/common";
import {createReadStream, ReadStream} from "fs";
import {Observable, of} from "rxjs";

@Controller("/")
export class KindOfResponseCtrl {
  @Get("/observable")
  observable(): Observable<any[]> {
    return of([]);
  }

  @Get("/stream")
  stream(): ReadStream {
    return createReadStream(__dirname + "/response.txt");
  }

  @Get("/stream")
  buffer(): Buffer {
    return Buffer.from("Hello");
  }
}
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# Axios response

5.48.0+

Sometime, you just want call another API to proxy a webservice. Axios is an excellent library to call API in Node.js and Ts.ED is able to handle Axios response to wrap it into an Express.js response.

import {Controller, Get, QueryParams, Res} from "@tsed/common";
import Axios from "axios";
import {IncomingMessage} from "http";

@Controller("/proxy")
export class ProxyCtrl {
  @Get("/")
  proxy(@QueryParams("path") path: string) {
    return Axios.get(`https://cerevoice.s3.amazonaws.com/${path}`, {
      responseType: "stream"
    });
  }

  // is equivalent to doing that
  @Get("/")
  async proxy2(@Res() res: Res, @QueryParams("path") path: string): IncomingMessage {
    const response = await Axios.get(`https://cerevoice.s3.amazonaws.com/${path}`, {
      responseType: "stream"
    });

    res.set(response.headers);
    res.status(response.status);

    return response.data;
  }
}
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# Multiple endpoints, single method

Ts.ED lets you define multiple endpoints on the same method, with the same verb like GET or POST, or with another verb like this:

import {Controller, Get, Post} from "@tsed/common";

@Controller("/calendars")
export class CalendarCtrl {
  @Get("/:id")
  @Get("/alias/:id")
  @Post("/:id/complexAlias")
  async get(): Promise<any> {
    return "Return something";
  }
}
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# Routes order

Be aware that routes registration order (methods order in classes) matters. Assume that you have a route that allows getting a calendar by its path (/calendars/:id). If you register another endpoint below the mentioned one, which basically returns all calendars at once (calendars), the request will never hit the actual handler because all path parameters are optional.

See the following example:

import {Controller, Get, PathParams} from "@tsed/common";

@Controller("/calendars")
export class CalendarsController {
  @Get(":id")
  findOne(@PathParams("id") id: string) {
    return `This action returns a #${id} cat`;
  }

  @Get()
  findAll() {
    // This endpoint will never get called
    // because the "/calendars" request is going
    // to be captured by the "/calendars/:id" route handler
  }
}
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In order to avoid such side-effects, simply move findAll() method above findOne().

# Request

# Input parameters

Getting parameters from Express Request can be done by using the following decorators:

  • : Express.request.body
  • : Express.request.params
  • : Express.request.params without transformation and validation,
  • : Express.request.query
  • : Express.request.query without transformation and validation,
import {BodyParams, Controller, Post} from "@tsed/common";
import {CalendarModel} from "../models/CalendarModel";
import {PayloadModel} from "../models/PayloadModel";


@Controller("/calendars")
export class CalendarCtrl {

  @Post()
  updatePayload(@BodyParams() payload: PayloadModel): any {
    console.log("payload", payload);

    return payload;
  }

  @Post()
  updateCalendar(@BodyParams("calendar") calendar: CalendarModel): any {
    console.log("calendar", calendar);

    return calendar;
  }

  @Post()
  updatePayloads(@BodyParams(PayloadModel) payloads: PayloadModel[]): any {
    console.log("payloads", payloads);

    return payloads;
  }

  @Post()
  updateCalendars(@BodyParams("calendars", CalendarModel) calendars: CalendarModel[]): any {
    console.log("calendars", calendars);

    return calendars;
  }
}
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Finally, accepts to give a object as parameter to change the decorator behavior:

import {BodyParams, Post} from "@tsed/common";

class MyController {
  @Post()
  async create(@BodyParams({expression: "user", useConverter: false}) body: T): Promise<T> {
    console.log("payload", body);

    return body;
  }
}
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TIP

Since v5.51.0+, decorator accept a model to transform Express.request.query plain object to a Class.

class QueryParamsModel {
  @Required()
  @MinLength(1)
  name: string;

  @Property()
  duration: number;
}

@Controller("/")
class QueryController {
  @Get("/")
  get(@QueryParams() params: QueryParamsModel, @QueryParams("locale") locale: string) {}
}
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# Headers

decorator provides you a quick access to the Express.request.get()

import {Controller, Get, HeaderParams} from "@tsed/common";

@Controller("/calendars")
export class CalendarCtrl {

  @Get()
  get(@HeaderParams("x-token") token: string): string {
    console.log("token", token);

    return token;
  }
}
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# Session/Cookies/Locals/Context

For the session, cookies, locals or context data attached on the request, it works the same way as seen before. Use the following decorators to get the data:

# Response

# Decorators

# Status

You can change the default response status with the decorator:

import {BodyParams, Controller, Put, Status} from "@tsed/common";

interface Calendar {
  id: string;
  name: string;
}

@Controller("/calendars")
export class CalendarCtrl {
  @Put("/")
  @Status(201)
  create(@BodyParams("name") id: string): Calendar {
    return {id: "2", name: "test"};
  }
}
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# Content Type

You can set the response content type with the decorator:

import {BodyParams, ContentType, Controller} from "@tsed/common";

@Controller("/calendars")
export class CalendarCtrl {
  @ContentType(".html")              // => 'text/html'
  @ContentType("html")               // => 'text/html'
  @ContentType("json")               // => 'application/json'
  @ContentType("application/json")   // => 'application/json'
  @ContentType("png")
  getContent(@BodyParams("name") name: string): any {
    return "something";
  }
}
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You can set the response header with the decorator:

import {BodyParams, Controller, Header} from "@tsed/common";

@Controller("/calendars")
export class CalendarCtrl {
  @Header({
    "Content-Type": "text/plain",
    "Content-Length": 123,
    "ETag": {
      "value": "12345",
      "description": "header description"
    }
  })
  create(@BodyParams("name") name: string): string {
    return `Text plain ${name}`;
  }
}
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# Throw exceptions

You can use @tsed/exceptions or similar module to throw an http exception. All exception will be intercepted by the Global error handler and are sent to the client.

Here is an example:

import {Controller, Get, PathParams} from "@tsed/common";
import {BadRequest} from "@tsed/exceptions";

@Controller("/calendars")
export class CalendarCtrl {
  @Get("/:id")
  get(@PathParams("id") id: number): any {
    if (isNaN(+id)) {
      throw(new BadRequest("Not a number"));
    }

    return {id};
  }
}
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TIP

This example will produce a response with status code 400 and "Not a number" message. will catch and format the error before sending it to the client.

# Inject request, response and next

You can use a decorator to inject Express.Request, Express.Response and Express.NextFunction services instead of the classic call provided by Express API.

Here an example to use these decorators:

import {Controller, Get, Next, Req, Res} from "@tsed/common";
import * as Express from "express";

@Controller("/calendars")
export class CalendarCtrl {
  @Get("/:id")
  get(
    @Req() request: Express.Request,
    @Res() response: Express.Response,
    @Next() next: Express.NextFunction
  ): void {
    setTimeout(() => {
      response
        .status(200)
        .send({id: request.params.id, name: "test"});
      next();
    });
  }
}
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# Inject router

Each controller has an Express.Router instance associated with it. The ExpressRouter decorator is here to inject this instance into your controller.

import {Controller, ExpressRouter} from "@tsed/common";

@Controller("/calendars")
export class CalendarCtrl {
  constructor(@ExpressRouter router: ExpressRouter) {
    router.get("/", this.myMethod);
  }

  myMethod(req: any, res: any, next: any) {
  }
}
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WARNING

In this case, injection on the method isn't available.

# Advanced usage

# Templating

A template engine like EJS or Handlebars can be used to change the response returned by your endpoint. Like Express.js, you need to configure the templating engine so that you can use it later with the decorator.

Here is an example of a controller which uses the decorator:

import {Controller, Get, Render} from "@tsed/common";

@Controller("/events")
export class EventCtrl {

  @Get("/:id")
  @Render("eventCard.ejs")
  public get(): any {
    return {startDate: new Date(), name: "MyEvent"};
  }
}
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And its view:

<h1><%- name %></h1>
<div>
    Start: <%- startDate %>
</div>
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TIP

To configure a template engine with Ts.ED, see our guide to install the engine rendering with Ts.ED.

# Middlewares

The middleware is a function which is called before the route handler. Middleware functions have access to the request and response objects, and the next middleware function in the application’s request-response cycle. The next middleware function is commonly denoted by a variable named next.

TIP

For more details about Middleware declaration see the Middlewares section.

The following decorators lets you add custom middleware on a method or on controller:

# Example

import {Controller, Get, PathParams, Use, UseAfter, UseBefore} from "@tsed/common";
import {CustomBeforeMdlw, CustomMiddleware} from "../middlewares/middlewares";

@Controller("/calendars")
@UseBefore(CustomBeforeMdlw)
export class CalendarCtrl {
  @Get("/:id")
  @Use(CustomMiddleware)
  get1(@PathParams("id") id: number): any {
    return {id};
  }

  @Get("/:id")
  @UseBefore(CustomMiddleware)
  get2(@PathParams("id") id: number): any {
    return {id};
  }

  @Get("/:id")
  @UseAfter(CustomMiddleware)
  get3(@PathParams("id") id: number): any {
    return {id};
  }
}
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# Middleware call sequence

When a request is sent to the server all middlewares added on the ServerLoader, Controller or Endpoint will be called while a response isn't sent by one of the middleware in the lifecycle.

TIP

See middlewares section for more information.

# Child controllers

A controller can have one or more child controllers. This feature allows you to combine your controllers with each other to define your routes. One controller can be added to multiple controllers, so you can easily reuse the same controller.

import {Controller, Get, RouteService, ServerLoader, ServerSettings} from "@tsed/common";

@Controller("/events")
export class EventCtrl {
  @Get()
  get() {
  }
}

@Controller({
  path: "/calendars",
  children: [EventCtrl]
})
export class CalendarCtrl {
  @Get()
  get() {
  }
}

@Controller({
  path: "/rest",
  children: [
    CalendarCtrl,
    EventCtrl
  ]
})
export class RestCtrl {
  constructor(private routeService: RouteService) {
  }

  @Get()
  get() {
    return this.routeService.printRoutes();
  }
}

@ServerSettings({
  mount: {
    "/": [
      RestCtrl
    ]
  }
})
class Server extends ServerLoader {
}
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This example will produce these following routes:

Verb Route Method
GET /rest RestCtrl.get()
GET /rest/calendars CalendarCtrl.get()
GET /rest/calendars/events EventCtrl.get()
GET /rest/events EventCtrl.get()

# Merge Params

In some cases you need to have complex routes like this rest/calendars/:calendarId/events/:eventId. This route can be written with Ts.ED like this :

import {Controller, Get, PathParams} from "@tsed/common";

@Controller("/:calendarId/events")
class EventCtrl {
  @Get("/:eventId")
  async get(
    @PathParams("calendarId") calendarId: string,
    @PathParams("eventId") eventId: string
  ) {
    console.log("calendarId =>", calendarId);
    console.log("eventId =>", eventId);
  }
} 
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In this case, the calendarId will be undefined because Express.Router didn't merge params by default from the parent Router (see Express documentation).

To solve it you can use the decorator. See this example:

import {Controller, Get, PathParams, MergeParams} from "@tsed/common";

@Controller("/:calendarId/events")
@MergeParams()
class EventCtrl {
  @Get("/:eventId")
  async get(
    @PathParams("calendarId") calendarId: string,
    @PathParams("eventId") eventId: string
  ) {
    console.log("calendarId =>", calendarId);
    console.log("eventId =>", eventId);
  }
}
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Now, calendarId will have the value given in the context path.

TIP

caseSensitive and strict options are also supported with their respective decorators and .

# Inheritance

Ts.ED supports the ES6 inheritance class. So you can declare a controller that implement some generic method and use it on a children class.

To do that just declare a parent controller without the decorator.

import {Get, QueryParams} from "@tsed/common";
import {SomeService} from "./SomeService";

export abstract class BaseCtrl {
  constructor(private someService: SomeService) {
  }

  @Get("/list")
  async list(@QueryParams("search") search: any) {
    return this.someService.list(search);
  }
}
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Then, on your child controller:

import {Controller, Get, PathParams} from "@tsed/common";
import {BaseCtrl} from "./BaseCtrl";

@Controller("/child")
export abstract class ChildCtrl extends BaseCtrl {
  @Get("/:id")
  get(@PathParams("id") id: string): any {
    return {id: id};
  }
}
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# Decorators