server/helpers/image-utils.ts

   1 import { copy, readFile, remove, rename } from 'fs-extra'
   2 import * as Jimp from 'jimp'
   3 import { getLowercaseExtension } from './core-utils'
   4 import { convertWebPToJPG, processGIF } from './ffmpeg-utils'
   5 import { logger } from './logger'
   6 import { buildUUID } from './uuid'
   7
   8 function generateImageFilename (extension = '.jpg') {
   9   return buildUUID() + extension
  10 }
  11
  12 async function processImage (
  13   path: string,
  14   destination: string,
  15   newSize: { width: number, height: number },
  16   keepOriginal = false
  17 ) {
  18   const extension = getLowercaseExtension(path)
  19
  20   if (path === destination) {
  21     throw new Error('Jimp/FFmpeg needs an input path different that the output path.')
  22   }
  23
  24   logger.debug('Processing image %s to %s.', path, destination)
  25
  26   // Use FFmpeg to process GIF
  27   if (extension === '.gif') {
  28     await processGIF(path, destination, newSize)
  29   } else {
  30     await jimpProcessor(path, destination, newSize, extension)
  31   }
  32
  33   if (keepOriginal !== true) await remove(path)
  34 }
  35
  36 // ---------------------------------------------------------------------------
  37
  38 export {
  39   generateImageFilename,
  40   processImage
  41 }
  42
  43 // ---------------------------------------------------------------------------
  44
  45 async function jimpProcessor (path: string, destination: string, newSize: { width: number, height: number }, inputExt: string) {
  46   let jimpInstance: Jimp
  47   const inputBuffer = await readFile(path)
  48
  49   try {
  50     jimpInstance = await Jimp.read(inputBuffer)
  51   } catch (err) {
  52     logger.debug('Cannot read %s with jimp. Try to convert the image using ffmpeg first.', path, { err })
  53
  54     const newName = path + '.jpg'
  55     await convertWebPToJPG(path, newName)
  56     await rename(newName, path)
  57
  58     jimpInstance = await Jimp.read(path)
  59   }
  60
  61   await remove(destination)
  62
  63   // Optimization if the source file has the appropriate size
  64   const outputExt = getLowercaseExtension(destination)
  65   if (skipProcessing({ jimpInstance, newSize, imageBytes: inputBuffer.byteLength, inputExt, outputExt })) {
  66     return copy(path, destination)
  67   }
  68
  69   await jimpInstance
  70     .resize(newSize.width, newSize.height)
  71     .quality(80)
  72     .writeAsync(destination)
  73 }
  74
  75 function skipProcessing (options: {
  76   jimpInstance: Jimp
  77   newSize: { width: number, height: number }
  78   imageBytes: number
  79   inputExt: string
  80   outputExt: string
  81 }) {
  82   const { jimpInstance, newSize, imageBytes, inputExt, outputExt } = options
  83   const { width, height } = newSize
  84
  85   if (jimpInstance.getWidth() > width || jimpInstance.getHeight() > height) return false
  86   if (inputExt !== outputExt) return false
  87
  88   const kB = 1000
  89
  90   if (height >= 1000) return imageBytes <= 200 * kB
  91   if (height >= 500) return imageBytes <= 100 * kB
  92
  93   return imageBytes <= 15 * kB
  94 }