Deno-Core

A compact, high-performance and full-featured web server framework in Deno.

Shortcut mode

import { core } from "https://deno.land/x/core/mod.ts";

core
  .get("/:user", (ctx) => ctx.params.user)
  .listen();

Note that features such as plugins, middlewares, template engine and unified error handling cannot be used in shortcut mode, you must solve them in other ways.

Decorator mode

Importing a ts/tsx file containing any decorators to use its features. Shortcut mode and decorator mode do not conflict and can be used together. The only difference in performance between the two is that the latter needs to parse all decorators at startup, it is almost the same in runtime.

// main.ts
import { core } from "https://deno.land/x/core/mod.ts";
import "./controllers/MyController.ts"; // Do not forget import the controllers

core.listen();

1. Controllers

// controller.ts
import { Context, Controller, Get } from "https://deno.land/x/core/mod.ts";

@Controller("/prefix")
export class MyController {
  @Get("/:user")
  getUser(ctx: Context) {
    return ctx.params.user;
  }
}

2. Middlewares

You can add middleware decorator on any class method, including controllers. The role of the middleware parameter is to set the execution priority.

// middleware.ts
import { Context, Middleware } from "https://deno.land/x/core/mod.ts";

export class MyMiddleware {
  @Middleware(2)
  cors(ctx: Context) {
    // do something second
  }
  @Middleware(1)
  auth(ctx: Context) {
    // do something first
  }
}

3. Plugins

Plugin decorators can only be added to classes, and the parameter is the name bound to the context.

// plugin.ts
import { Plugin } from "https://deno.land/x/core/mod.ts";

@Plugin("redis")
export class Redis {
  constructor() {
    // connect to redis server and create a client
  }
  get(key) {
    // do something
  }
  set(key, value) {
    // do something
  }
}

Then you can use redis object as singleton instance in any controllers with ctx.redis.

4. Templates

Template decorators are used to decorate controller methods, and its parameter is the template file path. After adding it the built-in template engine will be used for rendering automatically. The built-in engine is based on tmplet, You can go to the repo to see the template syntax.

// main.ts
core.engine({ // Engine options, not necessary
  root: "", // The root of template files
  imports: {} // Global imports for template
})
.listen();

// controller.ts
import { Context, Controller, Get, Template } from "https://deno.land/x/core/mod.ts";

@Controller("/prefix")
export class MyController {
  @Get("/:user")
  @Template("index.html") // or @Template("root/path/index.html") if engine not initialized
  getUser(ctx: Context) {
    return { name: ctx.params.user };
  }
}

// index.html
<h1>Hello, {{= name }}</h1>

5. JSX

// controller.ts
/** @jsx h */
import { Context, Controller, Get, h } from "https://deno.land/x/core/mod.ts";

const Homepage = ({ props }: any) => (
  <div>
    <h1>Hello, {props.name}</h1>
  </div>
);

@Controller()
export class JsxController {
  @Get("/jsx")
  jsx(ctx: Context) {
    const data = { name: "jsx" };
    return <Homepage props={data} />;
  }
}

6. ErrorHandler

If an error handler decorator is defined, all errors within the framework will be handled by it. Like middleware, you can define it in any class method but only once. This decorator has no parameters.

// error.ts
import { Context, ErrorHandler } from "https://deno.land/x/core/mod.ts";

export class AnyClass {
  @ErrorHandler()
  error(ctx: Context) {
    console.log(ctx.error);
  }
}

API Reference

Constructor

To start the web server, you simply write a single line of code core.listen(). The instance of core has three main methods as follow:

• serve(path) path is the relative path of static resources directory. serve method is the syntactic sugar for get routing, so the path must starts with “/”.
• engine(options) Initialize the built-in template engine. The default value of options is { root: "", imports: {} }.
• listen(port) HTTP server listening port, default 3000.

Routes

The route methods including all,get,post,put,del,patch,head,opt, and all methods have the same parameters. The internal router is based on radix tree, so you don’t need to consider the order of route. For more usage, please refer to: https://github.com/zhmushan/router.

• path Route path.
• callback Request handle function.

Decorators

Context

Context is an instance passed to controllers, middlewares and error handler, it contains properties and methods related to requests and responses.

Request Properties

• ctx.params The parameters on route path
• ctx.query The parameters on query string
• ctx.url ex. https://example.com:3000/users?page=1
• ctx.origin ex. https://example.com:3000
• ctx.protocol ex. https:
• ctx.host ex. example.com:3000
• ctx.hostname ex. example.com
• ctx.port ex. 3000
• ctx.path ex. /users
• ctx.method Standard http request methods
• ctx.headers Refer to https://deno.com/deploy/docs/runtime-headers
• ctx.cookies Including one method to get request cookie: ctx.cookies.get(name)
• ctx.body Including five promised methods to parse request body: text(), json(), form(), blob(), buffer().
• ctx.request Native request instance.

Response Properties

• ctx.status
• ctx.status=
• ctx.statusText
• ctx.statusText=
• ctx.cookies Including two methods to operate response cookie: set(name, value),delete(name)

Response Methods

• ctx.has(name) The following 5 methods are used to manipulate response headers
• ctx.get(name)
• ctx.set(name, value)
• ctx.append(name, value)
• ctx.delete(name)
• ctx.redirect(url[, status]) Redirect url with default status code 308.

Others

• ctx.view(tmplFile, data) If the controller method does not add a @Template decorator, you can call this method to return the rendered text content.
• ctx.render(tmplText, data) Render template text, usually not needed.
• ctx.renderJsx(node) Render template node, usually not needed.
• ctx.error
• ctx.throw(message[, status])

Return types

Controller methods are allowed to return the following object types：

• BodyInit: Blob, BufferSource, FormData, ReadableStream, URLSearchParams, or USVString
• Response: Native response instance.