138 lines
4.5 KiB
JavaScript
138 lines
4.5 KiB
JavaScript
var debug = require('debug')('ylt:imageReformater');
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var sharp = require('sharp');
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// Disable sharp cache to reduce the "disk is full" error on Amazon Lambda
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sharp.cache(false);
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var ImageOptimizer = function() {
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// https://www.industrialempathy.com/posts/avif-webp-quality-settings
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const WEBP_QUALITY = 82;
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const AVIF_QUALITY = 64;
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async function reformatImage(entry) {
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if (!entry.weightCheck || !entry.weightCheck.bodyBuffer) {
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// No valid file available
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return entry;
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}
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var fileSize = entry.weightCheck.uncompressedSize;
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debug('Let\'s try to convert %s to other image formats', entry.url);
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debug('Current file size is %d', fileSize);
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var animated = await isAnimated(entry);
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debug('Check if the file is animated: %s', animated);
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if (isJPEG(entry) || isPNG(entry)) {
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debug('File is %s, let\'s try to convert it to WebP', entry.contentType);
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try {
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const webpFile = await convertToWebp(entry.weightCheck.bodyBuffer, animated);
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if (webpFile) {
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var webpFileSize = webpFile.length;
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debug('WebP transformation complete for %s', entry.url);
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debug('WebP size is %d bytes', webpFileSize);
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if (webpFile.length > 0 && gainIsEnough(fileSize, webpFileSize)) {
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entry.weightCheck.webpSize = webpFileSize;
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debug('WebP size is %d bytes smaller (-%d%)', fileSize - webpFileSize, Math.round((fileSize - webpFileSize) * 100 / fileSize));
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}
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} else {
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debug('Convertion to WebP didn\'t work');
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}
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} catch(err) {
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debug('Error while converting to WebP, ignoring');
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}
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}
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if (!animated && (isJPEG(entry) || isPNG(entry) || isWebP(entry))) {
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debug('File is %s and is not animated, let\'s try to convert it to AVIF', entry.contentType);
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try {
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const avifFile = await convertToAvif(entry.weightCheck.bodyBuffer);
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if (avifFile) {
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var avifFileSize = avifFile.length;
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debug('AVIF transformation complete for %s', entry.url);
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debug('AVIF size is %d bytes', avifFileSize);
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if (avifFile.length > 0 && gainIsEnough(fileSize, avifFileSize)) {
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entry.weightCheck.avifSize = avifFileSize;
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debug('AVIF size is %d bytes smaller (-%d%)', fileSize - avifFileSize, Math.round((fileSize - avifFileSize) * 100 / fileSize));
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}
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} else {
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debug('Convertion to AVIF didn\'t work');
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}
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} catch(err) {
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debug('Error while converting to AVIF, ignoring');
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}
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}
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return entry;
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}
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async function convertToWebp(bodyBuffer, isAnimated) {
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return sharp(bodyBuffer, {animated: isAnimated})
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.webp({quality: WEBP_QUALITY, alphaQuality: WEBP_QUALITY})
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.toBuffer();
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}
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async function convertToAvif(bodyBuffer) {
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return sharp(bodyBuffer)
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.webp({quality: AVIF_QUALITY})
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.toBuffer();
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}
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// The gain is estimated of enough value if it's over 2KB or over 20%,
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// but it's ignored if is below 100 bytes
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function gainIsEnough(oldWeight, newWeight) {
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var gain = oldWeight - newWeight;
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var ratio = gain / oldWeight;
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return (gain > 2048 || (ratio > 0.2 && gain > 100));
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}
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function isJPEG(entry) {
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return entry.isImage && entry.contentType === 'image/jpeg';
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}
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function isPNG(entry) {
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return entry.isImage && entry.contentType === 'image/png';
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}
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function isWebP(entry) {
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return entry.isImage && entry.contentType === 'image/webp';
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}
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function entryTypeCanBeReformated(entry) {
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return isJPEG(entry) || isPNG(entry) || isWebP(entry);
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}
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async function isAnimated(entry) {
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if (isWebP(entry)) {
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const metadata = await sharp(entry.weightCheck.bodyBuffer).metadata();
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return metadata.pages > 1;
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}
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return false;
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}
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return {
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reformatImage: reformatImage,
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convertToWebp: convertToWebp,
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convertToAvif: convertToAvif,
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gainIsEnough: gainIsEnough,
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entryTypeCanBeReformated: entryTypeCanBeReformated,
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isAnimated: isAnimated
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};
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};
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module.exports = new ImageOptimizer(); |