image operations via Images.js, directory fun via Dirs.js

server/Images.js

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+import sizeOf from 'image-size'
+import fs from 'fs'
+import exif from 'exif'
+import sharp from 'sharp'
+import {UPLOAD_DIR, UPLOAD_URL} from './Dirs.js'
+
+const resizeImage = async (filename) => {
+  if (!filename.toLowerCase().match(/\.(jpe?g|webp|png)$/)) {
+    return
+  }
+
+  const imagePath = `${UPLOAD_DIR}/${filename}`
+  const imageOutPath = `${UPLOAD_DIR}/r/${filename}`
+  const orientation = await getExifOrientation(imagePath)
+
+  let sharpImg = sharp(imagePath, { failOnError: false })
+  // when image is rotated to the left or right, switch width/height
+  // https://jdhao.github.io/2019/07/31/image_rotation_exif_info/
+  if (orientation === 6) {
+    sharpImg = sharpImg.rotate()
+  } else if (orientation === 3) {
+    sharpImg = sharpImg.rotate().rotate()
+  } else if (orientation === 8) {
+    sharpImg = sharpImg.rotate().rotate().rotate()
+  }
+  const sizes = [
+    [150, 100],
+    [375, 210],
+  ]
+  for (let [w,h] of sizes) {
+    console.log(w, h, imagePath)
+    await sharpImg.resize(w, h, { fit: 'contain' }).toFile(`${imageOutPath}-${w}x${h}.webp`)
+  }
+}
+
+async function getExifOrientation(imagePath) {
+  return new Promise((resolve, reject) => {
+    new exif.ExifImage({ image: imagePath }, function (error, exifData) {
+      if (error) {
+        resolve(0)
+      } else {
+        resolve(exifData.image.Orientation)
+      }
+    })
+  })
+}
+
+const allImages = () => {
+  const images = fs.readdirSync(UPLOAD_DIR)
+    .filter(f => f.toLowerCase().match(/\.(jpe?g|webp|png)$/))
+    .map(f => ({
+      filename: f,
+      file: `${UPLOAD_DIR}/${f}`,
+      url: `${UPLOAD_URL}/${f}`,
+    }))
+    .sort((a, b) => {
+      return fs.statSync(b.file).mtime.getTime() -
+        fs.statSync(a.file).mtime.getTime()
+    })
+  return images
+}
+
+async function getDimensions(imagePath) {
+  let dimensions = sizeOf(imagePath)
+  const orientation = await getExifOrientation(imagePath)
+  // when image is rotated to the left or right, switch width/height
+  // https://jdhao.github.io/2019/07/31/image_rotation_exif_info/
+  if (orientation === 6 || orientation === 8) {
+    return {
+      width: dimensions.height,
+      height: dimensions.width,
+    }
+  }
+  return dimensions
+}
+
+export default {
+  allImages,
+  resizeImage,
+  getDimensions,
+}