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import { ensureDir } from 'https://deno.land/std@0.93.0/fs/ensure_dir.ts'import { createHash } from 'https://deno.land/std@0.93.0/hash/mod.ts'import { join } from 'https://deno.land/std@0.93.0/path/mod.ts'import { existsFileSync } from '../shared/fs.ts'import log from '../shared/log.ts'import util from '../shared/util.ts'import { getDenoDir } from './helper.ts'
/** download and cache remote contents */export async function cache(url: string, options?: { forceRefresh?: boolean, retryTimes?: number }) {  const { protocol, hostname, port, pathname, search } = new URL(url)  const hashname = createHash('sha256').update(pathname + search).toString()  const isLocalhost = hostname === 'localhost' || hostname === '0.0.0.0' || hostname === '127.0.0.1'  const cacheDir = join(    await getDenoDir(),    'deps',    util.trimSuffix(protocol, ':'),    hostname + (port ? '_PORT' + port : '')  )  const contentFilepath = join(cacheDir, hashname)  const metaFilepath = join(cacheDir, hashname + '.metadata.json')
  if (!options?.forceRefresh && !isLocalhost && existsFileSync(contentFilepath) && existsFileSync(metaFilepath)) {    const [content, meta] = await Promise.all([      Deno.readFile(contentFilepath),      Deno.readTextFile(metaFilepath),    ])    try {      const { headers = {} } = JSON.parse(meta)      return {        content,        contentType: headers['content-type'] || null      }    } catch (e) { }  }
  const retryTimes = options?.retryTimes || 3  let err = new Error('Unknown')  for (let i = 0; i < retryTimes; i++) {    if (i === 0) {      if (!isLocalhost) {        log.info('Download', url)      }    } else {      log.debug('Download error:', err)      log.warn(`Download ${url} failed, retrying...`)    }    try {      const resp = await fetch(url)      if (resp.status >= 400) {        return Promise.reject(new Error(resp.statusText))      }      const buffer = await resp.arrayBuffer()      const content = new Uint8Array(buffer)      if (!isLocalhost) {        const headers: Record<string, string> = {}        resp.headers.forEach((val, key) => {          headers[key] = val        })        await ensureDir(cacheDir)        Deno.writeFile(contentFilepath, content)        Deno.writeTextFile(metaFilepath, JSON.stringify({ headers, url }, undefined, 2))      }      return {        content,        contentType: resp.headers.get('content-type')      }    } catch (e) {      err = e    }  }
  return Promise.reject(err)}