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https://github.com/jrf0110/8track
A service worker router with async middleware and neato type-inference inspired by Koa
https://github.com/jrf0110/8track
Last synced: about 2 months ago
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A service worker router with async middleware and neato type-inference inspired by Koa
- Host: GitHub
- URL: https://github.com/jrf0110/8track
- Owner: jrf0110
- Created: 2019-05-22T18:37:45.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2024-06-19T21:25:16.000Z (3 months ago)
- Last Synced: 2024-07-21T01:23:35.493Z (2 months ago)
- Language: TypeScript
- Size: 733 KB
- Stars: 56
- Watchers: 4
- Forks: 6
- Open Issues: 13
-
Metadata Files:
- Readme: README.md
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README
# 8Track - A Service Worker Router
Wanted: a better logo
> A service worker router with async middleware and neato type-inference inspired by Koa
#### Installation
```
npm install -S 8track
-- Or yarn
yarn add 8track
```
##### TypeScript
This library is written in TypeScript, so typings are bundled.
#### Basic usage
```typescript
import { Router, handle } from '8track'
const router = new Router()
router.all`(.*)`.use(async (ctx, next) => {
console.log(`Handling ${ctx.event.request.method} - ${ctx.url.pathname}`)
await next()
console.log(`${ctx.event.request.method} - ${ctx.url.pathname}`)
})
router.get`/`.handle((ctx) => ctx.html('Hello, world!'))
router.all`(.*)`.handle((ctx) => ctx.end('Not found', { status: 404 }))
addEventListener('fetch', (event) => handle({ event, router }))
```
## Examples
#### Add CORS headers
```typescript
import { Router } from '8track'
const router = new Router()
router.all`(.*)`.use(async (ctx, next) => {
const allowedOrigins = ['https://www.myorigin.com']
const allowedHeaders = ['Content-type', 'X-My-Custom-Header']
const allowedMethods = ['GET', 'HEAD', 'PUT', 'POST', 'DELETE', 'PATCH']
ctx.response.headers.append('Vary', 'Origin')
ctx.response.headers.append('Access-Control-Allow-Origin', allowedOrigins.join(','))
ctx.response.headers.append('Access-Control-Allow-Headers', allowedHeaders.join(','))
ctx.response.headers.append('Access-Control-Allow-Methods', allowedMethods.join(','))
ctx.response.headers.append('Access-Control-Allow-Credentials', 'true')
if (ctx.req.method === 'OPTIONS') {
return ctx.end('', { status: 204 })
}
await next()
})
```
#### Catch all errors and display error page
```typescript
import { Router, getErrorPageHTML } from '8track'
const router = new Router()
addEventListener('fetch', (e) => {
const res = router.getResponseForEvent(e).catch(
(error) =>
new Response(getErrorPageHTML(e.request, error), {
status: 500,
headers: {
'Content-Type': 'text/html',
},
}),
)
e.respondWith(res as any)
})
```
#### Attach new properties to each request
Each Middleware and route handler receives a new copy of the ctx object, but a special object under the `data` property is mutable and should be used to share data between handlers
```typescript
interface User {
id: string
name: string
}
// Pretend this is a function that looks up a user by ID
async function getUserById(id: string): Promise {
return null as any
}
// The describes the shape of the shared data each middleware will use
interface RouteData {
user?: User
}
// This middleware attaches the user associated to the route to the request
const getUserMiddleware: Middleware = async (ctx, next) => {
ctx.data.user = await getUserById(ctx.params.userId)
await next()
}
const router = new Router()
// For all user requests, attach the user
router.all`/users/${'userId'}`.use(getUserMiddleware)
router.get`/users/${'userId'}`.handle((ctx) => {
if (!ctx.data.user) return ctx.end('Not found', { status: 404 })
ctx.json(JSON.stringify(ctx.data.user))
})
```
#### Sub-router mounting
```typescript
const apiRouter = new Router()
const usersRouter = new Router()
const userBooksRouter = new Router()
usersRouter.get`/`.handle((ctx) => ctx.end('users-list'))
usersRouter.get`/${'id'}`.handle((ctx) => ctx.end(`user: ${ctx.params.id}`))
userBooksRouter.get`/`.handle((ctx) => ctx.end('books-list'))
userBooksRouter.get`/${'id'}`.handle((ctx) => ctx.end(`book: ${ctx.params.id}`))
usersRouter.all`/${'id'}/books`.use(userBooksRouter)
apiRouter.all`/api/users`.use(usersRouter)
```
## API
### Router
Instantiate a new router
```typescript
const router = new Router<{ logger: typeof console.log }>()
```
#### .getResponseForEvent(request: FetchEvent): Promise | undefined
Given an event, run the matching middleware chain and return the response returned by the chain.
#### Router handlers and middleware
The primary way to interact with the router is to add routes via method tags:
```typescript
router.post`/api/users`.handle((ctx) => ctx.json({ id: 123 }))
```
In the above example, the `post` tag returns a [RouteMatchResult](#routematchresult) object.
##### Method Matchers
Each of these methods returns a [RouteMatchResult](#routematchresult) object.
- .all\`pattern\`
- .get\`pattern\`
- .post\`pattern\`
- .put\`pattern\`
- .patch\`pattern\`
- .delete\`pattern\`
- .head\`pattern\`
- .options\`pattern\`
### RouteMatchResult
When you use a template tag on the router, you create a RouteMatchResult.
```typescript
router.patch`/api/users/${'id'}` // RouteMatchResult
```
The RouteMatchResult object allows you to mount a route handler or a middleware that only runs when the pattern is matched.
```typescript
router.patch`/api/users/${'id'}`.use(async (ctx, next) => {
console.log('Before: User ID', ctx.params.id)
await next()
console.log('After: User ID', ctx.params.id)
})
```
#### .handle((ctx: Context) => any)
Mount a route handler that should return an instance of Response
#### .use((ctx: Context, next: () => Promise) => any)
Mount a route middleware that can optionally terminate the chain early and handle the request.
```typescript
router.patch`/api/users/${'id'}`.use(async (ctx, next) => {
console.log('Before: User ID', ctx.params.id)
if (ctx.params.id === '123') {
return ctx.end(Response.redirect(302))
}
await next()
console.log('After: User ID', ctx.params.id)
})
```
### Context
Each route handler and middleware receives an instance of `Context`.
#### Context Properties
- `readonly event: FetchEvent`
- `readonly params: Params`
- `response: Response`
- `data: Data`
- `url: URL`
#### Context Methods
- `end(body: string | ReadableStream | Response | null, responseInit: ResponseInit = {})`
- `html(body: string | ReadableStream, responseInit: ResponseInit = {})`
- `json(body: any, responseInit: ResponseInit = {})`
##### What's up with that weird syntax?
8track uses a JavaScript feature called [tagged templates](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals#Tagged_templates) in order to extract parameter names from url patterns. TypeScript is able extract types from tagged template literals:
```typescript
const bar = 123
const baz = new Date()
// Extracted type here is a tuple [number, Date]
foo`testing: ${bar} - ${baz} cool`
// But things get interesting when using literal types
// Extracted type here is a tuple ['bar', 'baz']
foo`testing: ${'bar'} - ${'baz'} cool`
```
Since the template literal is able to extract a tuple whose types are the _literal values_ passed in, we can utilize generics to describe the shape of the route parameters:
## Built-in Middleware
### KV Static
Serves files from Cloudflare KV.
```typescript
import { Router, kvStatic } from '8track'
const router = new Router()
router.all`(.*)`.use(kvStatic({ kv: myKvNamespaceVar, maxAge: 24 * 60 * 60 * 30 }))
```
## Deploying your worker
8track comes with a CLI to upload your worker and sync your kv files. In order to use 8track's kv [static file middleware](#kv-static), you must upload your files using this CLI.
Add a deploy script to your package.json:
```javascript
{
"scripts": {
"deploy": "8track deploy --worker dist/worker.js --kv-files dist/client.js,dist/client.css"
}
}
```
**Note**: This does not support globs yet!
You'll need the following environment variables set:
```bash
# Your Cloudflare API Token
CF_KEY
# Your Cloudflare account email
CF_EMAIL
# Your Cloudflare account ID
CF_ID
# The ID of the namespace
KV_NAMESPACE_ID
# The name of the KV namespace you want to use
KV_NAMESPACE
# The variable name your KV namespace is bound to
KV_VAR_NAME
```