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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

$ 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

Perl

#!/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;
}

Ruby

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) }
end

PHP

$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', $res);
curl_close($curl);

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.

Getting close to launching HTML2PDF Web Service!

For the last couple of months I’ve been busy developing HTML2PDF Web Service. Due to some setbacks I had to postpone its launch. The way it’s looking now I’ll be ready to launch by the end of the month.

So what had to change?

  • I had to switch from Payment Service Provider, which is done now. Instead of only credit cards I’m now supporting PayPal, iDEAL, Paysafe Card and Mister Cash. Credit Card support should come back later. Instead of recurring subscriptions you can now buy up to 1 year of access in advance. This is due to not being able to support recurring subscriptions anymore because of the PSP switch.
  • The website is now multilingual: currently supporting English and Dutch. Both have their own domain names. I’ve done this to get a better position in the Dutch market.

All that’s left now is changing the way token usage is being calculated and it should be all set to go. The HTML2PDF Web Service is still in beta, so feel free to try it out. Once the web service is out of beta I’ll do another post here with a follow up on used technology (Perl, Go and more!).

 

Help beta test an HTML2PDF Web Service

In an earlier post I asked if anyone would be interested to help me out test a web service for converting HTML to PDF. Today I’m opening up the beta to anyone that’s interested.

Please visit https://html2pdfwebservice.com/ and sign-up for a 7-day trial account. No credit card required! Trial length can be extended upon request.

Converting HTML to PDF is easy with the HTML2PDF Web Service. Here are some examples:

cURL

$ 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

Perl

#!/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;
}

Ruby

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) }
end

PS: Prices are subject to change. During the beta you can’t use your own credit card for payments since we’re still running in sandbox mode. All data will be wiped after the beta ends. Expected launch date will be some time in January 2014.

Propel ORM for PHP

For the last couple of weeks I’ve have been working with Propel ORM for PHP and have really enjoyed using it. Coming from Perl I’m spoiled because it has DBIx::Class which is my ORM by choice and makes fetching data from your SQL database including relational data a breeze. Propel does a really nice job with this as well and though the API differs greatly from that of DBIx::Class I found it easy enough to pick up.

Propel nicely integrates with Symfony 2 and I’m happy with my decision to go with Propel. The alternative would’ve been Doctrine but decided against using it, mainly because of having to learn DQL (Doctrine Query Language). DQL is similar to SQL, but I liked the named methods of Propel better (e.g. filterByCampaign($object) or filterByCampaignId($id)) and in the end with Doctrine you’re still busy writing a dialect of SQL. With Propel and DBIx::Class you can still use SQL when needed (and to be honest I still find it to be a bit awkward at times in DBIx::Class but I understand why it is the way it is). I could also have looked at Zend_Db_Table from Zend Framework which I’ve used in the past but found too limiting.

All in all Propel a nice ORM library for PHP. Be sure to check it out if you haven’t already.

 

Maximus has been taken down

As of today Maximus, the BlitzMax Module Manager, has been taken down. I’ve blogged about this some time ago and today I’ve decided it was finally time to go through with it. The website now redirects to the GitHub organization that hosts the code for the client and the website. These will still be available online of course.

So what does this mean for Maximus and BlitzMax?

  1. The Maximus client can no longer fetch the sources file from the Maximus website and thus it can no longer download modules from the website as well. You’re back to downloading and installing BlitzMax modules manually yourself. If you’ve got a Maximus webapp instance running somewhere you can however configure the client to use the sources file from there.
  2. Development on both the client and webapp had stopped some time ago, but I would still fix bugs if they popped up. With the cancellation of the hosted webapp this also means I won’t be doing any development on Maximus anymore.
  3. With the source code being available anyone is free to host their own Maximus instance. Since the webapp uses Vagrant and Puppet you should be able to get a local instance running quickly. There’s also an INSTALL file for manual installation on Ubuntu.

Developing Maximus and providing this service has been a fun ride of which I’ve learned a lot and resulted in a well crafted piece of software. I can however no longer provide the service and support it and so it’s time to move on. I want to thank everyone who has supported Maximus in any way possible. Thanks.