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import type { MiddlewareHandler } from '../../types.ts'import { sha1 } from '../../utils/crypto.ts'
type ETagOptions = {  weak: boolean}
export const etag = (options: ETagOptions = { weak: false }): MiddlewareHandler => {  return async (c, next) => {    const ifNoneMatch = c.req.header('If-None-Match') || c.req.header('if-none-match')
    await next()
    const res = c.res as Response    const clone = res.clone()    const hash = await sha1(res.body || '')
    const etag = options.weak ? `W/"${hash}"` : `"${hash}"`
    if (ifNoneMatch && ifNoneMatch === etag) {      await clone.blob() // Force using body      c.res = new Response(null, {        status: 304,        statusText: 'Not Modified',        headers: {          ETag: etag,        },      })      c.res.headers.delete('Content-Length')    } else {      c.res = new Response(clone.body, clone)      c.res.headers.append('ETag', etag)    }  }}