@bogeychan/elysia-etag

A plugin for Elysia.js for automatic HTTP ETag generation

Installation

bun add @bogeychan/elysia-etag

Usage

import { Elysia } from 'elysia'
import { etag } from '@bogeychan/elysia-etag'

const app = new Elysia()
    .use(etag())
    .get('/', () => 'Checkout the response headers!')
    .get('/custom-etag', (ctx) => {
        // This line disables automatic ETag generation
        // It will still return a 304 - Not Modified - status code if the ETag matches
        ctx.setETag('"myETag"')
        return 'Hello ETag!'
    })
    .listen(3000)

console.log(`Listening on ${app.server!.url}`)

Use serialize to convert incompatible data to a hashable format

With JSON

new Elysia()
    .use(
        etag({
            serialize(response) {
                if (typeof response === 'object') {
                    return JSON.stringify(response)
                }
            }
        })
    )
    .get('/', () => ({ my: 'json' }))

With BunFile

new Elysia()
    .use(
        etag({
            serialize(response) {
                if (response instanceof Blob && 'lastModified' in response) {
                    // based on last modified UNIX timestamp
                    return (response as BunFile).lastModified.toString()

                    // based on file content
                    return (response as BunFile).bytes()
                }
            }
        })
    )
    .get('/', () => Bun.file('./file.txt'))

Provide your own hash function

let myInsecureChangeCounter = 0

new Elysia()
    .use(
        etag({
            hash: (response) => {
                return (response as string) + myInsecureChangeCounter++
            }
        })
    )
    .get('/', () => 'Checkout the response headers!')

Checkout the examples folder on github for further use cases.

Credits ❤️

This project was inspired by @fastify/etag

Author

bogeychan

License

MIT