Creating a Resource

A resource is a class that maps a set of paths to its HTTP method handlers. Drash defines resources according to the MDN:

• What is a URL? 
• Overview of HTTP 

Unlike other frameworks, Drash does not use app.get() and does not use controllers. Instead, Drash uses resources. You create a resource by defining a resource class, its routes as its paths property, and its HTTP method handlers as public methods that match the HTTP method name. For example:

import { Resource } from "@drashland/drash/modules/http.native.js";
 
class IndexResource extends Resource {
  public paths = ["/"];
 
  public GET(request) {
    return new Response(`Received GET request`);
  }
 
  public POST(request) {
    return new Response(`Received POST request`);
  }
}

• If a resource specifies / in its paths property, then clients can go to {your-site.com}/.
• If a resource specifies /my-resource in its paths property, then clients can go to {your-site.com}/my-resource.
• and so on…

Any path that does not exist in any resource is considered a non-accessible URI. Non-accessible URIs ultimately lead to a 404 Not Found error response.

Any HTTP method that is not defined in a resource ultimately leads to a 501 Not Implemented error response.

Dynamic Paths

Paths can carry parameters and regular expressions, so one resource can cover many endpoints.

Required Path Params

Required path params follow the :name_of_your_path_param syntax.

import { Resource } from "@drashland/drash/modules/http.native.js";
 
class ResourceWithPathParam extends Resource {
  public paths = ["/:my_cool_param"];
 
  public GET(request) {
    return new Response(`You passed in: ${request.params.pathParam("my_cool_param")}`);
  }
}

Making the following requests will result in the following responses:

Optional Path Params

A trailing ? makes a param optional, so the resource matches with or without it.

import { Resource } from "@drashland/drash/modules/http.native.js";
 
class UsersResource extends Resource {
  // id is required; the rest are optional
  public paths = ["/users/:id/:name?/:age?/:city?"];
 
  public GET(request) {
    const id = request.params.pathParam("id");
    const name = request.params.pathParam("name");
    return new Response([id, name].filter(Boolean).join(" | "));
  }
}

Making the following requests will result in the following responses:

Regular Expression Paths

import { Resource } from "@drashland/drash/modules/http.native.js";
 
class RegexPathResource extends Resource {
  public paths = ["/([0-9]$)"];
 
  public GET(request) {
    return new Response("GOT!");
  }
}

HTTP Methods

Defining HTTP Methods

You can define any of the following methods in your resource.

• CONNECT
• `DELETE
• GET
• HEAD
• OPTIONS
• PATCH
• `POST
• PUT
• TRACE

Each receives the input that was passed to app.handle() and you return whatever your runtime needs.

Every method you do not define throws a 501 Not Implemented error response. That is the base class’ default behavior, following RFC 7231 Section 4.1 .

Methods may be synchronous or asynchronous; app.handle() awaits whatever they return.

Return Values

Whatever an HTTP method returns becomes the resolved value of app.handle(). For runtimes that support Web Request/Response, the HTTP method should return Response. Otherwise, the HTTP method should return whatever the runtime needs. In Node, you do not have to return anything since it expects you to write directly to the ServerResponse object it gives you.