npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

@eggjs/koa

v2.19.1

Published

Koa web app framework for https://eggjs.org

Downloads

180

Readme

@eggjs/koa

@eggjs/koa is forked from Koa v2.x for LTS and drop Node.js < 18.19.0 support.

NPM version NPM download Node.js CI Test coverage Known Vulnerabilities

Expressive HTTP middleware framework for node.js to make web applications and APIs more enjoyable to write. Koa's middleware stack flows in a stack-like manner, allowing you to perform actions downstream then filter and manipulate the response upstream.

Only methods that are common to nearly all HTTP servers are integrated directly into Koa's small codebase. This includes things like content negotiation, normalization of node inconsistencies, redirection, and a few others.

Koa is not bundled with any middleware.

Installation

@eggjs/koa requires node v18.19.0 or higher for Node.js LTS support.

npm install @eggjs/koa

Hello Koa

import { Application } from '@eggjs/koa';

const app = new Application();

// response
app.use((ctx) => {
  ctx.body = 'Hello Koa';
});

app.listen(3000);

Getting started

  • Kick-Off-Koa - An intro to Koa via a set of self-guided workshops.
  • Workshop - A workshop to learn the basics of Koa, Express' spiritual successor.
  • Introduction Screencast - An introduction to installing and getting started with Koa

Middleware

Koa is a middleware framework that can take two different kinds of functions as middleware:

  • async function
  • common function

Here is an example of logger middleware with each of the different functions:

async functions

app.use(async (ctx, next) => {
  const start = Date.now();
  await next();
  const ms = Date.now() - start;
  console.log(`${ctx.method} ${ctx.url} - ${ms}ms`);
});

Common function

// Middleware normally takes two parameters (ctx, next), ctx is the context for one request,
// next is a function that is invoked to execute the downstream middleware. It returns a Promise with a then function for running code after completion.

app.use((ctx, next) => {
  const start = Date.now();
  return next().then(() => {
    const ms = Date.now() - start;
    console.log(`${ctx.method} ${ctx.url} - ${ms}ms`);
  });
});

Context, Request and Response

Each middleware receives a Koa Context object that encapsulates an incoming http message and the corresponding response to that message. ctx is often used as the parameter name for the context object.

app.use(async (ctx, next) => {
  await next();
});

Koa provides a Request object as the request property of the Context.
Koa's Request object provides helpful methods for working with http requests which delegate to an IncomingMessage from the node http module.

Here is an example of checking that a requesting client supports xml.

app.use(async (ctx, next) => {
  ctx.assert(ctx.request.accepts('xml'), 406);
  // equivalent to:
  // if (!ctx.request.accepts('xml')) ctx.throw(406);
  await next();
});

Koa provides a Response object as the response property of the Context.
Koa's Response object provides helpful methods for working with http responses which delegate to a ServerResponse .

Koa's pattern of delegating to Node's request and response objects rather than extending them provides a cleaner interface and reduces conflicts between different middleware and with Node itself as well as providing better support for stream handling. The IncomingMessage can still be directly accessed as the req property on the Context and ServerResponse can be directly accessed as the res property on the Context.

Here is an example using Koa's Response object to stream a file as the response body.

app.use(async (ctx, next) => {
  await next();
  ctx.response.type = 'xml';
  ctx.response.body = fs.createReadStream('really_large.xml');
});

The Context object also provides shortcuts for methods on its request and response. In the prior examples, ctx.type can be used instead of ctx.response.type and ctx.accepts can be used instead of ctx.request.accepts.

For more information on Request, Response and Context, see the Request API Reference, Response API Reference and Context API Reference.

Koa Application

The object created when executing new Koa() is known as the Koa application object.

The application object is Koa's interface with node's http server and handles the registration of middleware, dispatching to the middleware from http, default error handling, as well as configuration of the context, request and response objects.

Learn more about the application object in the Application API Reference.

Documentation

Troubleshooting

Check the Troubleshooting Guide or Debugging Koa in the general Koa guide.

Running tests

npm test

Reporting vulnerabilities

To report a security vulnerability, please do not open an issue, as this notifies attackers of the vulnerability. Instead, please email fengmk2 to disclose.

Community

License

MIT

Contributors

Contributors

Made with contributors-img.