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skava / @skava/react-server js

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@skava/react-server / src / middleware / cacheMiddleware.ts
/**
 * @file @todo split
 */
import { Request, Response } from 'express'
import { remove } from 'fs-jetpack'
import { read, write, exists } from 'flipfile'
import { fromRequestToHash } from 'uxui-modules/oneRequest/deps/fromRequestToHash'
import { resolveToRoot } from '@skava/bs'
import { NextFunction } from 'express'
import {
  fromStringToSanitizedFileName,
  truncate,
} from '../deps/fromStringToSanitizedFileName'

// @todo should be in routeParams but nobody should edit this file and muck encoding
// unless they have a mac or are careful
const emoji = {
  moneyWithWings: '💸',
  moneyBags: '💰',
}
const cacheAddressMap = {
  moneyWithWings: encodeURI(emoji.moneyWithWings),
  moneyBags: encodeURI(emoji.moneyBags),
}
Object.freeze(emoji)
Object.freeze(cacheAddressMap)

/**
 * @see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control
 */
function respondFromCache(
  req: Request,
  res: Response,
  cachedContents?: string
) {
  res.setHeader('cached', true)
  res.status(200)
  res.send(`<!DOCTYPE html>${cachedContents}`)
  res.end()
}

// @lint - logs
// eslint-disable-next-line
function fromReqResToRespondFromCacheExistence(req: Request, res: Response) {
  const hash = fromRequestToHash(res, '/react/') + req.oneUrl.full
  const sanitizedHash = fromStringToSanitizedFileName(hash)
  const cachedHashedPath = resolveToRoot(
    process.env.CACHE_SSR_OUTPUT_DIRECTORY + sanitizedHash
  )
  const shortHashedPath = truncate(cachedHashedPath, 255)
  req.cachedHashedPath = shortHashedPath

  console.info('[SSR] SHOULD_CACHE_SSR for: ', shortHashedPath)

  if (exists(shortHashedPath) === true) {
    console.info('[SSR] hash exists')
    const cachedContents = read(shortHashedPath)
    respondFromCache(req, res, cachedContents)
    return true
  }

  return false
}

/**
 * @throws hopefully not, but safety first
 */
function deleteCache() {
  try {
    remove(process.env.CACHE_SSR_OUTPUT_DIRECTORY)
  } catch (safetyFirstException) {
    console.error(
      '[ERROR_NOTIFY] [CACHE] remove exception!!! ',
      safetyFirstException
    )
  }
}

/**
 * @todo !!! add security to `knownParams` not just any random params to bypass cache
 * @todo avoid writing too many caches
 * @todo limit total cache size setting
 * @todo @security jwt
 */
function respondCash(req: Request, res: Response) {
  // res.status(205)
  const html = `<iframe width="560" height="315" src="https://www.youtube.com/embed/VTpNFBp3vbg?autoplay=1" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>`
  res.status(200).send(`<!DOCTYPE html>${html}`)
  res.end()
}

/**
 * @description handle cachings
 */
function cacheMiddleware(req: Request, res: Response, next: NextFunction) {
  const url = req.oneUrl.full

  const isCacheRequest =
    url.includes('cacheclear') ||
    url.includes(cacheAddressMap.moneyWithWings) ||
    url.includes(emoji.moneyWithWings)

  if (isCacheRequest) {
    // .debug
    console.log('[CACHE] isCacheRequest')
    deleteCache()
    respondCash(req, res)
    return
  }

  const SHOULD_CACHE_SSR =
    url.includes('cashmoney') ||
    url.includes(emoji.moneyBags) ||
    url.includes(cacheAddressMap.moneyBags) ||
    process.env.SHOULD_CACHE_SSR

  req.SHOULD_CACHE_SSR = SHOULD_CACHE_SSR

  next()
}

/**
 * @todo iterate through routes, render, output
 */
function cacheIfNeeded(req: Request, res: Response, html: string) {
  if (req.SHOULD_CACHE_SSR) {
    console.info('[SSR] cacheIfNeeded: caching')
    write(req.cachedHashedPath, html)
  }
}

/**
 * @description iterate routes, call them, output cache...
 */
function precacheRoutes() {
  console.log('@todo read description, @see precache')
}

/**
 * @todo https://github.com/addyosmani/critical/blob/master/README.md
 */
function optimizeCache() {
  //
}

export {
  precacheRoutes,
  respondFromCache,
  cacheIfNeeded,
  fromReqResToRespondFromCacheExistence,
  cacheMiddleware,
}
skava / @skava/react-server js

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