Optimize remote image processing

server/helpers/image-utils.ts

@@ -1,10 +1,9 @@
-import { remove, rename } from 'fs-extra'
+import { copy, readFile, remove, rename } from 'fs-extra'
+import * as Jimp from 'jimp'
 import { extname } from 'path'
 import { convertWebPToJPG, processGIF } from './ffmpeg-utils'
 import { logger } from './logger'
 
-const Jimp = require('jimp')
-
 async function processImage (
   path: string,
   destination: string,
@@ -23,7 +22,7 @@ async function processImage (
   if (extension === '.gif') {
     await processGIF(path, destination, newSize)
   } else {
-    await jimpProcessor(path, destination, newSize)
+    await jimpProcessor(path, destination, newSize, extension)
   }
 
   if (keepOriginal !== true) await remove(path)
@@ -37,11 +36,12 @@ export {
 
 // ---------------------------------------------------------------------------
 
-async function jimpProcessor (path: string, destination: string, newSize: { width: number, height: number }) {
-  let jimpInstance: any
+async function jimpProcessor (path: string, destination: string, newSize: { width: number, height: number }, inputExt: string) {
+  let jimpInstance: Jimp
+  const inputBuffer = await readFile(path)
 
   try {
-    jimpInstance = await Jimp.read(path)
+    jimpInstance = await Jimp.read(inputBuffer)
   } catch (err) {
     logger.debug('Cannot read %s with jimp. Try to convert the image using ffmpeg first.', path, { err })
 
@@ -54,8 +54,34 @@ async function jimpProcessor (path: string, destination: string, newSize: { widt
 
   await remove(destination)
 
+  // Optimization if the source file has the appropriate size
+  if (await skipProcessing({ jimpInstance, newSize, imageBytes: inputBuffer.byteLength, inputExt, outputExt: extname(destination) })) {
+    return copy(path, destination)
+  }
+
   await jimpInstance
     .resize(newSize.width, newSize.height)
     .quality(80)
     .writeAsync(destination)
 }
+
+function skipProcessing (options: {
+  jimpInstance: Jimp
+  newSize: { width: number, height: number }
+  imageBytes: number
+  inputExt: string
+  outputExt: string
+}) {
+  const { jimpInstance, newSize, imageBytes, inputExt, outputExt } = options
+  const { width, height } = newSize
+
+  if (jimpInstance.getWidth() > width || jimpInstance.getHeight() > height) return false
+  if (inputExt !== outputExt) return false
+
+  const kB = 1000
+
+  if (height >= 1000) return imageBytes <= 200 * kB
+  if (height >= 500) return imageBytes <= 100 * kB
+
+  return imageBytes <= 15 * kB
+}