Ant

Fast, simple and versatile web server framework.

NOTE: This is NOT production ready yet!

Table Of Contents

• Ant
• Table Of Contents
• About
  • The Goal
• Guide
  • Hello World
  • Using Routers
  • Route Workflow
  • Making Routes Type Consistent
  • Error handling
    • Throwing Errors
    • Defining Error Handling Process
• API Reference
  • Application
    • Application.METHOD
    • Application.mount(path: string, router: Router)
    • Application.error(...handlers)
    • Application.use(...handlers)
    • Application.run(addr: string | HTTPOptions, cb?: () => void)
  • Router
    • Router.METHOD
  • RequestCtx
    • url: string
    • method: string
    • headers: string
    • body
  • ResponseCtx
    • status(code: number)
    • set(…headers: string, string)
    • cookie(c: Cookie)
    • send(d: Uint8Array | Deno.Reader | string)

About

Ant is a web server framework wrapping around the standart Deno http library with zero 3rd party dependencies.

The Goal

To provide a framework that gives full control of the application state to the developer, has a wide range of standartized tools and a simple to use interface for building complex web apps.

Guide

Hello World

Import and create an instance of Application. Define the routes using Application.[METHOD] and run your web application with Application.run

import { Application } from "https://deno.land/x/ant@v0.1.1/mod.ts";

const app = new Application();

app.get(
  "/",
  async (req, res) => {
    console.log("handler 1");
  },
  async (req, res) => {
    console.log("handler 2");

    res.status(200).send("hello world!").text();
  }
);

app.run({ port: 8000 }, () => {
  console.log("Listening on port 8000");
});

Using Routers

When building a large web app, having your routes defined in one place is redundant. To break up and/or group your routes, use Router and then mount it to the Application by using Application.mount

// router.ts

import { Router } from "https://deno.land/x/ant@v0.1.1/mod.ts";

const router = new Router();

router.get(
  "/",
  async (req, res) => {
    console.log("middleware 1");
  },
  async (req, res) => {
    console.log("middleware 2");

    res.status(200).send("hello world!");
  }
);

export default router;

// index.ts

import { Application } from "https://deno.land/x/ant@v0.1.1/mod.ts";
import router from "./router.ts";

const app = new Application();

app.mount("/", router);

app.run({ port: 8000 }, () => {
  console.log("Listening on port 8000");
});

Route Workflow

Each route holds an array of handlers that process the request. These handlers are executed one by one until the last handler has been reached. If the response is not sent or an error is not thrown, the server will send a default response payload with status: 200 and an empty body.

Making Routes Type Consistent

When defining routes using Application.[METHOD] or Router.[METHOD], there is an option to declare generic types for RequestCtx.params, RequestCtx.query and RequestCtx.body that will persist throughout all route handlers.

type params

P - corresponds to RequestCtx.params types.

Q - corresponds to RequestCtx.query types.

B - corresponds to RequestCtx.body types.

type ReqParams = {
  id: string,
  foo: string,
  bar: string,
};

type ReqQuery = {
  name: string,
};

router.get<P = ReqParams, Q = ReqQuery>(
  "/:id/:foo/:bar",
  async (req, res) => {
    console.log("handler 1");
  },
  async (req, res) => {
    console.log("handler 2");

    res.status(200).send("hello world!");
  }
);

Error handling

When an error is thrown using either error() or throw keyword the Ant application will stop executing the route handlers and go straight to error handling process.

By default Ant application DOES NOT know how to handle errors. Error handling NEEDS to be defined by the developer using Application.error.

Throwing Errors

As mentioned before, there are two ways of throwing an error:

Using throw keyword:

app.get("/", async (req, res) => {
  throw new Error("Opps!"); // this will be cought

  res.status(200).send("hello world!");
});

Or using error() function:

app.get("/", async (req, res, error) => {
  error(new Error("Opps!")); // this will be cought

  res.status(200).send("hello world!");
});

IMPORTANT: you don’t need to use try...catch blocks for each route handler, unless you are doing asynchronous work.

Defining Error Handling Process

By default if the error handler does not send back a response using res.send, the Ant application will send a default error response payload with status: 500 and an empty body.

app.error(
  async (err, req, res) => {
    console.log(req.url, err); // Error logging
  },
  async (err, req, res) => {
    const response = {
      message: err.message,
    };

    // Send a response back to client with an error
    res.status(500).send(JSON.stringify(response)).json();
  }
);

API Reference

Application

Application.[METHOD](path: string, ...steps: Callback[])

Defines a HTTP route, where METHOD is one of supported HTTP methods

Application.mount(path: string, router: Router)

Mounts Router and its contents to the Application.

Application.error(...handlers)

Used to define the error handling process.

Application.use(...handlers)

Used to define Application-Level handlers.

Application.run(addr: string | HTTPOptions, cb?: () => void)

Starts the web server process with the specified address addr and an optional callback cb function that is executed before the web server process.

Router

Router.[METHOD](path: string, ...Callback[])

Defines a HTTP route, where METHOD is one of HTTP methods (GET, POST, DELETE, PUT, …)

RequestCtx

Holds information about the incoming request.

The supported properties of RequestCtx are:

url: string

RequestCtx.url returns a string that represents the endpoint of a request.

# full path
http://localhost:8000/customers

# RequestCtx.url output:
/customers

method: string

RequestCtx.method returns a string that represents the HTTP method that was used for the request.

headers: string

RequestCtx.headers returns a Header object which holds and/or manipulates the headers of a request.

body

RequestCtx.body contains key-value pairs of data that was submitted in the request. The RequestCtx.body returns getter properties that return the body of the request in a specific format. The supporter formats are:

ResponseCtx

Holds and controls the response data, that can be sent back to the client.

status(code: number)

Sets the status code of the response.

set(…headers: [string, string][])

Sets headers of the response.

cookie(c: Cookie)

Sets a cookie to the response object.

send(d: Uint8Array | Deno.Reader | string)

Sets the response body and sends it to the client. To send the response body in a specific format .send() exports few methods for that: