@throneless/libsignal-service/src/AttachmentHelper.js

A fork of the the libtextsecure components of Signal-Desktop, adapted for use by nodejs.

/*
 * vim: ts=2:sw=2:expandtab
 */



const debug = require('debug')('libsignal-service:Attachment');
const fs = require('fs').promises;
const path = require('path');
const mime = require('mime-types');
const sizeOf = require('image-size');
const getGuid = require('uuid/v4');
const helpers = require('./helpers.js');

function isImage(mimeType) {
  return mimeType.startsWith('image/');
}

// eslint-disable-next-line no-unused-vars
function isVideo(mimeType) {
  return mimeType.startsWith('video/');
}

// eslint-disable-next-line no-unused-vars
function isAudio(mimeType) {
  return mimeType.startsWith('audio/');
}

function contentTypeToFileName(mimeType) {
  switch (mimeType) {
    case 'image/jpeg':
      return '.jpg';
    case 'image/gif':
      return '.gif';
    case 'image/png':
      return '.png';
    case 'video/mp4':
      return '.mp4';
    case 'text/plain':
      return '.txt';
    default:
      return '.bin';
  }
}

// eslint-disable-next-line no-unused-vars
function loadFile(file, caption = '') {
  const source = path.normalize(file);
  const fileName = path.basename(source);
  const contentType = mime.lookup(source);
  debug(`Reading file ${  source  } with MIME type ${  contentType}`);
  return fs.readFile(source).then(buffer => {
    const data = helpers.convertToArrayBuffer(buffer);
    let width; let height;
    if (helpers.isString(contentType) && isImage(contentType)) {
      const dimensions = sizeOf(source);
      width = dimensions.width;
      height = dimensions.height;
    }
    return {
      fileName,
      contentType,
      width,
      height,
      data,
      size: data.byteLength,
    };
  });
}

async function saveFile(file, dest) {
  if (!file || !file.data || !file.contentType) {
    throw new Error('Invalid file.');
  }

  let {fileName} = file;
  if (!fileName) {
    const extension = contentTypeToFileName(file.contentType);
    const guid = getGuid();
    fileName = `${  guid  }${extension}`;
  }
  const target = path.join(dest, fileName);
  return fs.writeFile(target, Buffer.from(file.data)).then(() => target);
}

exports = module.exports = {
  loadFile,
  saveFile,
};