micro-image-manager/lib/util/image-util.js

Manage images in your microservices

"use strict";

function _extends() { _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; }; return _extends.apply(this, arguments); }

const sharp = require('sharp');

const os = require('os');

const crypto = require("crypto");

const path = require("path");

const FORMATS = {
  png: [{
    format: 'png',
    rank: 3
  }, {
    format: 'webp',
    rank: 1
  }],
  jpg: [{
    format: 'jpeg',
    rank: 2
  }, {
    format: 'webp',
    rank: 1
  }],
  jpeg: [{
    format: 'jpeg',
    rank: 2
  }, {
    format: 'webp',
    rank: 1
  }],
  gif: [{
    format: 'gif',
    rank: 4
  }, {
    format: 'webp',
    rank: 1
  }]
};

const buildImageRecords = async (imageFile, profiles) => {
  const records = [];
  const suggestedFormats = await suggestConvertingFormats(imageFile);

  for (let profile of profiles) {
    for (let suggestedFormat of suggestedFormats) {
      const resizedImage = await resizeImage(imageFile, profile, suggestedFormat.format, suggestedFormat.originalFormat);
      records.push({
        image: resizedImage,
        profile,
        format: suggestedFormat.format,
        originalFormat: suggestedFormat.originalFormat,
        formatPriority: suggestedFormat.formatPriority
      });
    }
  }

  return records;
};

const suggestConvertingFormats = async file => {
  const meta = await sharp(file).metadata();
  const formats = FORMATS[meta.format];

  if (!formats) {
    throw new Error(`Format ${meta.format} is not supported`);
  }

  return formats.map(format => _extends({
    originalFormat: meta.format
  }, format));
};

const resizeImage = async (file, profile, format, originalFormat) => {
  const process = sharp(file).resize(profile.width, profile.height);

  switch (format) {
    case 'png':
      process.png();
      break;

    case 'webp':
      process.webp({
        lossless: originalFormat == 'png' || originalFormat == 'gif'
      });
      break;

    case 'jpeg':
      process.webp();
      break;

    case 'gif':
      process.webp({
        lossless: originalFormat == 'png' || originalFormat == 'gif'
      });
      break;
  }

  const tempFile = path.join(os.tmpdir(), crypto.randomBytes(16).toString('hex') + '.' + format);
  await process.toFile(tempFile);
  return tempFile;
};

module.exports = {
  buildImageRecords
};