hono/README.md

Hono

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

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

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

app.fire()

Features

• Ultra fast - the router is implemented with Trie-Tree structure. Not use loops.
• Zero dependencies - using only Web standard API.
• Middleware - builtin middleware, and you can make your own middleware.
• Optimized - for Cloudflare Workers.

Benchmark

Hono is fastest compared to other routers for Cloudflare Workers.

hono x 708,671 ops/sec ±2.58% (58 runs sampled)
itty-router x 159,610 ops/sec ±2.86% (87 runs sampled)
sunder x 322,846 ops/sec ±2.24% (86 runs sampled)
worktop x 223,625 ops/sec ±2.01% (95 runs sampled)
Fastest is hono
✨  Done in 57.83s.

Hono in 1 minute

Below is a demonstration to create an application of Cloudflare Workers with Hono.

Install

You can install from npm registry:

yarn add hono

or

npm install hono

Methods

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

app.HTTP_METHOD

// 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')
})

app.all

// 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')
  ...

Chained Route

app
  .route('/api/book')
    .get(() => {...})
    .post(() => {...})
    .put(() => {...})

Custom 404 Response

You can customize 404 Not Found response:

app.get('*', (c) => {
  return c.text('Custom 404 Error', 404)
})

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!'))

Handling Error

app.use('*', async (c, next) => {
  try {
    await next()
  } catch (err) {
    console.error(`${err}`)
    c.res = c.text('Custom Error Message', { status: 500 })
  }
})

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')

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

c.text()

Render text 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.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
  ...
})

fire

app.fire() do:

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 this:
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 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 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 like http://127.0.0.1:8787/ in your Web browser.

wrangler dev

7. Publish

Deploy to Cloudflare. That's all!

wrangler publish

Related projects

Implementation of the router is inspired by goblin. 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

Contributing

Contributions Welcome! You can contribute by the following way:

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

If you can, let's make Hono together!

Author

Yusuke Wada https://github.com/yusukebe

License

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