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Duplicati – an alternative for Rackspace Cloud Files Sync

I’ve been using Rackspace Cloud Files Sync, a little piece of software I’ve written myself, for some years now. I use it to backup my photo’s and movies I’ve shot over the last decade or so. The thing I like about it is that it syncs your local folder with a Cloud Files container. When skipping content checksums it’s fairly fast to only process the changes. Aside from backing up files it can also restore them.

Whilst it still serves my need I get in trouble if or when Rackspace changes their Cloud Files API. Way back when I wrote the software I wrote it in BlitzMax with the MaxGUI module (using the excellent LogicGUI designer) and my own htbaapub.rackspacecloudfiles module. Sure, I can update my module that wraps the REST API but I no longer have an up to date BlitzMax with all the required modules set up on a PC. When I took Maximus offline the most convenient way to install BlitzMax modules and their dependencies disappeared. In short, it’ll be a big hassle to get a working setup again capable of compiling a new version of Rackspace Cloud Files Sync.

But today I found out about a software called Duplicati! Duplicati is backup software that can create and store backups to several kind of storage solutions such as Rackspace Cloud Files, Amazon S3, Windows Live SkyDrive, FTP, SSH and more. It can also encrypt your backups.

After a short test using Duplicati with Cloud Files I’ve at least found a nice alternative for when my Rackspace Cloud Files Sync stops working. The only thing I’m missing though is doing a full backup and then sync the changes like my software does, but it appears that this is already supported in the 2.0 preview release of Duplicati. So it’s likely that if or when my software stops working I can use the 2.0 release of Duplicati.

Monkey X Pro – 30% Discount

Monkey X ProA couple of days ago I received an e-mail by Blitz Research Ltd offering me a nice discount on Monkey X Pro, which I took advantage of. To show some love towards BRL and Monkey X Pro I thought I would share the offer here.

Monkey X Pro is a programming language for creating games which can be deployed to several targets including, but not limited to, Android, iOS, HTML5, Desktop, XNA, Ouya and more.

When you buy Monkey X Pro simply enter the coupon code MONKEYX30 for a 30% discount.

Now go buy it and support BRL!

Note: this offer is only available for a limited time and is available until 2nd June.

Enabling Bash auto-completion in Ubuntu

Virtual Private Servers are usually installed with the minimum required software. More often than not this means Bash auto-completion isn’t enabled, which is a tad bit annoying as it slows down navigation.

To fix this you can install the bash-completion package. Like so:

$ sudo apt-get intall bash-completion

Keeping VirtualBox Guest Additions in sync with Vagrant

Whenever you’re upgrading the software packages on your VirtualBox machine, managed by Vagrant, you risk VirtualBox Guest Additions render unusable and thus your shared folders don’t work anymore. This usually happens whenever a kernel upgrade is being done which requires the VirtualBox drivers to be recompiled.

Thanks to a Vagrant plugin called vbguest you can now safely upgrade your software packages. If you’ve got this plugin installed every time you run vagrant up it’ll check the installed version of VirtualBox Guest Additions and updates it accordingly.

To install the plugin run the following command from your shell:

$ vagrant plugin install vagrant-vbguest

Convert HTML to PDF with HTML2PDF Web Service

HTML2PDF Web ServiceRecently I launched my new product HTML2PDF Web Service — a web service for converting HTML to PDF.

In this post I’d like to talk about HTML2PDF Web Service. Why to choose it, how to use it and what technologies were used to create it.

Why Choose HTML2PDF Web Service?

Programmatically generating PDF documents is a painful and time consuming problem that neither makes your developers nor designers happy. With HTML2PDF Web Service you can design your invoices or reports in HTML, style them with CSS and convert the resulting page into a PDF document. Using HTML2PDF Web Service saves your developers and designers time which is better spent making your product better.

Say your web application or mobile app (or any application for that matter) needs to generate invoices or reports in PDF format. Unless you can install special HTML to PDF conversion software you’re probably stuck with some of the libraries available for your language that can programmatically generate PDF documents. To do this you would probably design your document in something like MS Word, LibreOffice Writer or perhaps HTML. After this design has been approved you can start programming your PDF module; setting up coordinates, font sizes etc. And then all of the sudden you notice your library has limited support for doing actual document layouts and presenting tabular data that can span multiple lines. Now you need to write your own routines for splitting text over multiple lines, keep track of coordinates and make sure nothing overlaps. If like me you’ve already been there, it’s quite the nightmare.

So being able to design in HTML, style with CSS (heck, even use a bit of JavaScript) and convert the resulting page to PDF would speed up this process a lot. Am I starting to tickle your interest?

How to use HTML2PDF Web Service

Simply create your soon to be PDF documents in HTML, style them with CSS and if wanted you can use JavaScript as well. The final document is best previewed in a WebKit based browser such as Google Chrome, since that’s the technology HTML2PDF Web Service uses in the background to render the HTML and convert it to PDF.

Here are some examples on how to call the web service. Converting HTML to PDF is easy with the HTML2PDF Web Service. You can pass an URL to the page you want to convert or either send the HTML code with the request.


$ curl -H "X-API-Key: F8802062-4D31-11E3-8F59-BFD4058B6BFF"
       -H "X-API-Username: MyUsername"
       -d '{"content":"<html><head><title>My page</title></head><body><h1>Hello World!</h1><p>I am an HTML page converted to PDF!</p></body></html>"}'
       https://html2pdfwebservice.com/api/convert > page.pdf


#!/usr/bin/env perl
use strict;
use warnings;
use Mojo::UserAgent;

my $ua = Mojo::UserAgent->new;
my $tx = $ua->post(
    'https://html2pdfwebservice.com/api/convert' => {
        'X-API-Username' => 'MyUsername',
        'X-API-Key'      => 'F8802062-4D31-11E3-8F59-BFD4058B6BFF'
    } => json => {url => 'http://domain.com/invoice.html'}
if (my $res = $tx->success) {
    my $pdf_data = $res->body;


require 'net/https'
require 'uri'

uri           = URI.parse('https://html2pdfwebservice.com/api/convert')
https         = Net::HTTP.new(uri.host, uri.port)
https.use_ssl = true
# In case the SSL certificate isn't accepted
https.verify_mode = OpenSSL::SSL::VERIFY_NONE

req = Net::HTTP::Post.new(uri.path)
req['X-API-Username'] = 'MyUsername'
req['X-API-Key']      = 'F8802062-4D31-11E3-8F59-BFD4058B6BFF'
req.body              = '{"url": "http://domain.com/invoice.html"}'

res = https.request(req)
if res.code == '200'
    pdf_data = res.body
    # - or write to file -
    # File.open('invoice.pdf', 'w') { |file| file.write(res.body) }


$settings = array(
    'url' => 'http://domain.com/invoice.html',

$curl = curl_init();
curl_setopt($curl, CURLOPT_POST, 1);
curl_setopt($curl, CURLOPT_POSTFIELDS, json_encode($settings));
curl_setopt($curl, CURLOPT_HTTPHEADER, array(
    'X-API-Username: MyUsername',
    'X-API-Key: F8802062-4D31-11E3-8F59-BFD4058B6BFF'

curl_setopt($curl, CURLOPT_URL, 'https://html2pdfwebservice.com/api/convert');
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
// Helps to debug in case of issues
// curl_setopt($curl, CURLOPT_VERBOSE, 1);

// In case the SSL certificate isn't accepted because of outdated certificates
// on your server
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);

$res = curl_exec($curl);
// Save PDF to disk
file_put_contents('document.pdf', $res);

Technologies used to develop HTML2PDF Web Service

The most interesting part in developing HTML2PDF Web Service was choosing which technology to use for converting HTML to PDF. After doing research on the subject and testing several solutions I eventually went with a WebKit based solution. By using WebKit it’s easier for the end user to preview their document using a WebKit based browser.

The HTML to PDF conversion server was developed using Go. Go is a fun language to program with, does concurrency in a really nice way and can produce a native executable for Linux, OS X, Windows and some other platforms. Thanks to Go the conversion server is fast, snappy and low on memory and CPU usage. Being able to create a binary executable allows me to sell the conversion server as a standalone product as well.

To get access to the web service there’s also a web application which is written in Perl. My favorite web framework of choice has become Mojolicious for quite some time now and thus HTML2PDF Web Service has been written with it. DBIx::Class has been used for database interaction and Validation::Class is used to validate all user inputted data.

Used databases are PostgreSQL and Redis. The former is used to store user accounts, subscriptions and more. The latter is used to keep track of token usage per user.

Sign up now for a free trial

If after reading all this and you’re still reading, please do sign up for a free trial. The trial gives full access to all the features of the web service so if you like it, please consider buying a subscription.

In case of any questions, please do contact me either through the comments on this page or send an e-mail to support at support@html2pdfwebservice.com.