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Fetch, resize via ImageMagick and store image on Amazon S3 with node.js
var spawn = require('child_process').spawn,
aws2js = require('aws2js'),
http = require('http'),
urlutil = require('url')
mime = require('mime'),
Buffers = require('buffers');
var settings = {
s3: {
key: 'key',
secret: 'secret',
bucket: 'bucket',
path: '/path/',
endpoint: ''
imageFormats: {
thumbnail: '-thumbnail 250x250^> -gravity center -extent 177x177 -filter Lanczos png24:-',
full: '-resize 1024x768 jpg:-',
var s3 = aws2js.load('s3', settings.s3.key, settings.s3.secret);
// Initiate a request
var req = http.get(urlutil.parse(''), function(res) {
// Set format name and fetch arguments from settings
var format ='thumbnail';
var args = settings.imageFormats[format];
// Spawn ImageMagic convert process
var proc = spawn('convert', ['-'].concat(args.split(' ')));
proc.stderr.on('data', function(err) {
console.log('Conversion failed:', err.toString());
// Pipe the result to our convert process
// We have to store the conversion result in a buffer because S3
// requires exact Content-Length header
var buffer = new Buffers();
proc.stdout.on('data', buffer.push.bind(buffer));
proc.stdout.on('end', function() {
var type = res.headers['Content-Type'];
var extension = mime.extension(type);
var path = settings.s3.path + shortid.generate() + '.' + extension + ':' format; // We append the format to make it easier to have several images with the same name
// S3 requires headers
var headers = {
'content-type': type,
'x-amz-acl': 'public-read'
s3.putBuffer(path, buffer.toBuffer(), false, headers, function(err) {
if (err) return console.error('Error storing:', err.toString());
console.log('Stored image:', path);

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@lokertmin lokertmin commented Jul 30, 2020

proc.stdout.on('data', buffer.push.bind(buffer));

should be proc.stdout.on('data', () => buffer.push.bind(buffer));

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