Hono

Hono[炎] - means flame🔥 in Japanese - is small, simple, and ultrafast web framework for Service Worker based serverless applications like Cloudflare Workers and Fastly Compute@Edge.

import { Hono } from 'hono'
const app = new Hono()

app.get('/', (c) => c.text('Hono!!'))

app.fire()

Features

• Ultrafast - the router does not use linear loops.
• Zero-dependencies - using only Web standard API.
• Middleware - builtin middleware and your own middleware.
• Optimized - for Cloudflare Workers.

Benchmark

Hono is fastest compared to other routers for Cloudflare Workers.

hono x 779,197 ops/sec ±6.55% (78 runs sampled)
itty-router x 161,813 ops/sec ±3.87% (87 runs sampled)
sunder x 334,096 ops/sec ±1.33% (93 runs sampled)
worktop x 212,661 ops/sec ±4.40% (81 runs sampled)
Fastest is hono
✨  Done in 58.29s.

Hono in 1 minute

A demonstration to create an application of Cloudflare Workers with Hono.

Now, the named path parameter has types.

Install

You can install Hono from the npm registry.

$ yarn add hono

or

$ npm install hono

Methods

An instance of Hono has these methods.

• app.HTTP_METHOD(path, handler)
• app.all(path, handler)
• app.route(path)
• app.use(path, middleware)
• app.fire()
• app.fetch(request, env, event)

Routing

Basic

// HTTP Methods
app.get('/', (c) => c.text('GET /'))
app.post('/', (c) => c.text('POST /'))

// Wildcard
app.get('/wild/*/card', (c) => {
  return c.text('GET /wild/*/card')
})

// Any HTTP methods
app.all('/hello', (c) => c.text('Any Method /hello'))

Named Parameter

app.get('/user/:name', (c) => {
  const name = c.req.param('name')
  ...
})

Regexp

app.get('/post/:date{[0-9]+}/:title{[a-z]+}', (c) => {
  const date = c.req.param('date')
  const title = c.req.param('title')
  ...
})

Nested route

const book = app.route('/book')
book.get('/', (c) => c.text('List Books')) // GET /book
book.get('/:id', (c) => {
  // GET /book/:id
  const id = c.req.param('id')
  return c.text('Get Book: ' + id)
})
book.post('/', (c) => c.text('Create Book')) // POST /book

no strict

If strict is set false, /helloand/hello/ are treated the same. Default is true.

const app = new Hono({ strict: false })

app.get('/hello', (c) => c.text('/hello or /hello/'))

async/await

app.get('/fetch-url', async (c) => {
  const response = await fetch('https://example.com/')
  return c.text(`Status is ${response.status}`)
})

Middleware

Builtin Middleware

import { Hono } from 'hono'
import { poweredBy } from 'hono/powered-by'
import { logger } from 'hono/logger'
import { basicAuth } from 'hono/basicAuth'

const app = new Hono()

app.use('*', poweredBy())
app.use('*', logger())
app.use(
  '/auth/*',
  basicAuth({
    username: 'hono',
    password: 'acoolproject',
  })
)

Available builtin middleware are listed on src/middleware.

Custom Middleware

You can write your own middleware.

// Custom logger
app.use('*', async (c, next) => {
  console.log(`[${c.req.method}] ${c.req.url}`)
  await next()
})

// Add a custom header
app.use('/message/*', async (c, next) => {
  await next()
  await c.header('x-message', 'This is middleware!')
})

app.get('/message/hello', (c) => c.text('Hello Middleware!'))

Context

To handle Request and Reponse, you can use Context object.

c.req

// Get Request object
app.get('/hello', (c) => {
  const userAgent = c.req.headers.get('User-Agent')
  ...
})

// Shortcut to get a header value
app.get('/shortcut', (c) => {
  const userAgent = c.req.header('User-Agent')
  ...
})

// Query params
app.get('/search', (c) => {
  const query = c.req.query('q')
  ...
})

// Captured params
app.get('/entry/:id', (c) => {
  const id = c.req.param('id')
  ...
})

Shortcuts for Response

app.get('/welcome', (c) => {
  c.header('X-Message', 'Hello!')
  c.header('Content-Type', 'text/plain')
  c.status(201)

  return c.body('Thank you for comming')
})

The Response is the same as below.

new Response('Thank you for comming', {
  status: 201,
  statusText: 'Created',
  headers: {
    'X-Message': 'Hello',
    'Content-Type': 'text/plain',
    'Content-Length': '22',
  },
})

c.text()

Render texts as Content-Type:text/plain.

app.get('/say', (c) => {
  return c.text('Hello!')
})

c.json()

Render JSON as Content-Type:application/json.

app.get('/api', (c) => {
  return c.json({ message: 'Hello!' })
})

c.html()

Render HTML as Content-Type:text/html.

app.get('/', (c) => {
  return c.html('<h1>Hello! Hono!</h1>')
})

c.notFound()

Return the default 404 Not Found Response.

app.get('/notfound', (c) => {
  return c.notFound()
})

c.redirect()

Redirect, default status code is 302.

app.get('/redirect', (c) => c.redirect('/'))
app.get('/redirect-permanently', (c) => c.redirect('/', 301))

c.res

// Response object
app.use('/', (c, next) => {
  next()
  c.res.headers.append('X-Debug', 'Debug message')
})

c.event

// FetchEvent object
app.use('*', async (c, next) => {
  c.event.waitUntil(
    ...
  )
  await next()
})

c.env

// Environment object for Cloudflare Workers
app.get('*', async c => {
  const counter = c.env.COUNTER
  ...
})

Not Found

You can write the default 404 Not Found Response.

app.notFound = (c) => {
  return c.text('This is default 404 Not Found', 404)
}

Error handling

You can handle errors in your way.

app.onError = (err, c) => {
  return c.text(`This is error message: ${err.mssage}`, 500)
}

fire

app.fire() do this.

addEventListener('fetch', (event) => {
  event.respondWith(this.handleEvent(event))
})

fetch

app.fetch() is for Cloudflare Module Worker syntax.

export default {
  fetch(request: Request, env: Env, event: FetchEvent) {
    return app.fetch(request, env, event)
  },
}

/*
or just do:
export default app
*/

Cloudflare Workers with Hono

Using wrangler or miniflare, you can develop the application locally and publish it with few commands.

Let's write your first code for Cloudflare Workers with Hono.

1. Install Wrangler

Install Cloudflare Command Line "Wrangler".

$ npm i @cloudflare/wrangler -g

2. npm init

Make a npm skeleton directory.

mkdir hono-example
cd hono-example
npm init -y

3. wrangler init

Init as a wrangler project.

$ wrangler init

4. npm install hono

Install hono from the npm registry.

$ npm i hono

5. Write your app

Only 4 lines!!

import { Hono } from 'hono'
const app = new Hono()

app.get('/', (c) => c.text('Hello! Hono!'))

app.fire()

6. Run

Run the development server locally. Then, access http://127.0.0.1:8787/ in your Web browser.

$ wrangler dev

7. Publish

Deploy to Cloudflare. That's all!

$ wrangler publish

Starter template

You can start making your application of Cloudflare Workers with the starter template. It is a realy minimal using TypeScript, esbuild, and Miniflare.

To generate a project skelton, run this command.

$ wrangler generate my-app https://github.com/yusukebe/hono-minimal

Related projects

Implementation of the original router TrieRouter is inspired by goblin. RegExpRouter is inspired by Router::Boom. API design is inspired by express and koa. itty-router, Sunder, and worktop are the other routers or frameworks for Cloudflare Workers.

• express https://github.com/expressjs/express
• koa https://github.com/koajs/koa
• itty-router https://github.com/kwhitley/itty-router
• Sunder https://github.com/SunderJS/sunder
• goblin https://github.com/bmf-san/goblin
• worktop https://github.com/lukeed/worktop
• Router::Boom https://github.com/tokuhirom/Router-Boom

Contributing

Contributions Welcome! You can contribute by the following way.

• Write or fix documents
• Write code of middleware
• Fix bugs
• Refactor the code
• etc.

Let's make Hono together!

Contributors

Thanks to all contributors!

Author

Yusuke Wada https://github.com/yusukebe

License

Distributed under the MIT License. See LICENSE for more information.