honojs-middleware/packages/bun-compress/src/index.ts

104 lines
3.8 KiB
TypeScript

/**
* @module
* Compress Middleware for Hono.
*/
import type { MiddlewareHandler } from 'hono'
import { compress as originalCompress } from 'hono/compress'
import { COMPRESSIBLE_CONTENT_TYPE_REGEX } from 'hono/utils/compress'
import { Readable } from 'node:stream'
import type { ReadableStream } from 'node:stream/web'
import { createDeflate, createGzip } from 'node:zlib'
const ENCODING_TYPES = ['gzip', 'deflate'] as const
const cacheControlNoTransformRegExp = /(?:^|,)\s*?no-transform\s*?(?:,|$)/i
interface CompressionOptions {
encoding?: (typeof ENCODING_TYPES)[number]
threshold?: number
}
/**
* Compress Middleware for Hono on Bun.
*
* Bun does not currently support CompressionStream, so this uses the zlib module to compress the response body.
*
* @see {@link https://hono.dev/docs/middleware/builtin/compress}
* @see {@link https://github.com/oven-sh/bun/issues/1723}
*
* @param {CompressionOptions} [options] - The options for the compress middleware.
* @param {'gzip' | 'deflate'} [options.encoding] - The compression scheme to allow for response compression. Either 'gzip' or 'deflate'. If not defined, both are allowed and will be used based on the Accept-Encoding header. 'gzip' is prioritized if this option is not provided and the client provides both in the Accept-Encoding header.
* @param {number} [options.threshold=1024] - The minimum size in bytes to compress. Defaults to 1024 bytes.
* @returns {MiddlewareHandler} The middleware handler function.
*
* @example
* ```ts
* const app = new Hono()
*
* app.use(bunCompress())
* ```
*/
export const compress = (options?: CompressionOptions): MiddlewareHandler => {
// Check CompressionStream support
if (typeof CompressionStream !== 'undefined') {
return originalCompress(options)
}
const threshold = options?.threshold ?? 1024
return async function compress(ctx, next) {
await next()
const contentLength = ctx.res.headers.get('Content-Length')
// Check if response should be compressed
if (
ctx.res.headers.has('Content-Encoding') || // already encoded
ctx.res.headers.has('Transfer-Encoding') || // already encoded or chunked
ctx.req.method === 'HEAD' || // HEAD request
(contentLength && Number(contentLength) < threshold) || // content-length below threshold
!shouldCompress(ctx.res) || // not compressible type
!shouldTransform(ctx.res) // cache-control: no-transform
) {
return
}
const accepted = ctx.req.header('Accept-Encoding')
const encoding =
options?.encoding ?? ENCODING_TYPES.find((encoding) => accepted?.includes(encoding))
if (!encoding || !ctx.res.body) {
return
}
// Compress the response
try {
const compressedStream = encoding === 'gzip' ? createGzip() : createDeflate()
const readableBody = ctx.res.body as ReadableStream
const readableStream = Readable.fromWeb(readableBody)
const compressedBody = readableStream.pipe(compressedStream)
const compressedReadableStream = Readable.toWeb(compressedBody) as ReadableStream<Uint8Array>
// Create a new response with the compressed body
// eslint-disable-next-line @typescript-eslint/no-explicit-any
ctx.res = new Response(compressedReadableStream as any, ctx.res)
ctx.res.headers.delete('Content-Length')
ctx.res.headers.set('Content-Encoding', encoding)
} catch (error) {
console.error('Compression error:', error)
}
}
}
const shouldCompress = (res: Response) => {
const type = res.headers.get('Content-Type')
return type && COMPRESSIBLE_CONTENT_TYPE_REGEX.test(type)
}
const shouldTransform = (res: Response) => {
const cacheControl = res.headers.get('Cache-Control')
// Don't compress for Cache-Control: no-transform
// https://tools.ietf.org/html/rfc7234#section-5.2.2.4
return !cacheControl || !cacheControlNoTransformRegExp.test(cacheControl)
}