Jailbreaking WordPress with Web hooks

As is often the case, I struggle at first glance to see the full implications of a new development in technology, which is why I so often rely on others to kick me up the arse before I get it.1

Where I ramble about WordPress as a learning tool for the web…

I first read about web hooks while looking at WordPress, XMPP and FriendFeed’s SUP and then again when writing about PubSubHubbub. Since then, Dave Winer’s RSSCloud has come along, too, so there’s now plenty of healthy competition in the world of real time web and WordPress is, predictably, a mainstream testing ground for all of it. Before I go on to clarify my understanding of the implications of web hooks+WordPress, I should note that my main interest here is not web hooks nor specifically the real time web, which is interesting but realistically, not something I’m going to pursue with fervour. My main interest is that WordPress is an interesting and opportunistic technology platform for users, administrators and developers, alike. Whoever you are, if you want to understand how the web works and how innovations become mainstream, WordPress provides a decent space for exercising that interest. I find it increasingly irritating to explain WordPress in terms of ‘blogging’. I’ve very little interest in WordPress as a blog. I tend to treat WordPress as I did Linux, ten years ago. Learning about GNU/Linux is a fascinating, addictive and engaging way to learn about Operating Systems and the role of server technology in the world we live in. Similarly, I have found that learning about WordPress and, perhaps more significantly, the ecosystem of plugins and themes2 is instructive in learning about the technologies of the web. I encourage anyone with an interest, to sign up to a cheap shared host such as Dreamhost, and use their one-click WordPress offering to set up your playground for learning about the web. The cost of a domain name and self-hosting WordPress need not exceed $9 or £7/month.3

… and back to web hooks

Within about 15 minutes of Tony tweeting about HookPress, I had watched the video, installed the plugin and sent a realtime tweet using web hooks from WordPress.

It’s pretty easy to get to grips with and if a repository of web hook scripts develops, even the non-programmers like me could make greater use of what web hooks offer.

Web hooks are user-defined callbacks over HTTP. They’re intended to, in a sense, “jailbreak” our web applications to become more extensible, customizable, and ultimately more useful. Conceptually, web applications only have a request-based “input” mechanism: web APIs. They lack an event-based output mechanism, and this is the role of web hooks. People talk about Unix pipes for the web, but they forget: pipes are based on standard input and standard output. Feeds are not a sufficient form of output for this, which is partly why Yahoo Pipes was not the game changer some people expected. Instead, we need adoption of a simple, real-time, event-driven mechanism, and web hooks seem to be the answer. Web hooks are bringing a new level of event-based programming to the web.

I think the use of the term ‘jailbreak’ is useful in understanding what HookPress brings to the WordPress ecosystem. WordPress is an application written in PHP and if you wish to develop a plugin or theme for WordPress you are required to use the PHP programming language. No bad thing but the HookPress plugin ‘jailbreaks’ the requirement to work with WordPress in PHP by turning WordPress’ hooks (‘actions’ and ‘filters’) into web hooks.

WordPress actions and filters, are basically inbuilt features that allow developers to ‘hook’ into WordPress with their plugins and themes. Here’s the official definition:

Hooks are provided by WordPress to allow your plugin to ‘hook into’ the rest of WordPress; that is, to call functions in your plugin at specific times, and thereby set your plugin in motion. There are two kinds of hooks:

  1. Actions: Actions are the hooks that the WordPress core launches at specific points during execution, or when specific events occur. Your plugin can specify that one or more of its PHP functions are executed at these points, using the Action API.
  2. Filters: Filters are the hooks that WordPress launches to modify text of various types before adding it to the database or sending it to the browser screen. Your plugin can specify that one or more of its PHP functions is executed to modify specific types of text at these times, using the Filter API.

So, if I understand all this correctly, what HookPress does is turn WordPress hooks into web hooks which post the output of the executed actions or filters to scripts written in other languages such as Python, Perl, Ruby and Javascript (they can be written in PHP, too) hosted elsewhere on the web.   In the example given in the HookPress video, the WordPress output of the action, ‘publish_post‘, along with two variables ‘post_title’ and ‘post_url’, was posted to a script hosted on scriptlets.org,  which performs the event of sending a tweet which includes the title and URL of the WordPress post that has just been published. All this happens as fast as the component parts of the web allows, i.e. in ‘real time’.

In other words, what is happening is that WordPress is posting data to a URL, where lies a script, which takes that data and creates an event which notifies another application. Because the scripts can be hosted elsewhere, on large cloud platforms such as Google’s AppEngine, the burden of processing events can be passed off to somewhere else. I see now, why web hooks are likened to Unix pipes, in that the “output of each process feeds directly as input to the next one” and so on. In the case of HookPress, the output of the ‘publish_post’ hook feeds directly as input to the scriptlet and the output of that feeds directly as input to the Twitter API which outputs to the twitter client.

Besides creating notifications from WordPress actions, the other thing that HookPress does (still with me on this ‘learning journey’ ??? I’ve been reading, writing and revising this blog post for hours now…), is extend the functionality of WordPress through the use of WordPress filters. Remember that filters in WordPress, modify text before sending it to the database and/or displaying it on your computer screen. The example in the video, shows the web hook simply reversing the text before it is rendered on the screen. ‘This is a test’ becomes ‘tset a si sihT’.

The output of the ‘the_content‘ filter has been posted to the web hook, which has reversed the order of the blog post content and returned it back to WordPress which renders the modified blog post.

Whereas the action web hooks are about providing event-driven notifications, the filter web hooks allow developers to extend the functionality of WordPress itself in PHP and other scripting languages.  In both cases, web hooks ‘jailbreak’ WordPress by turning it into a single process in a series of piped processes where web hooks create, modify and distribute data.

Finally, I’ll leave you with this presentation, which is all about web hooks.

In the presentation, there are two quotes which I found useful. One from Wikipedia which kind of summarises what HookPress is doing to WordPress:

“In computer programming, hooking is a technique used to alter or augment the behaviour of [a programme], often without having access to its source code.”

and another from Marc Prensky, which relates back to my point about using WordPress as a way to learn about web technologies in a broader sense. WordPress+HookPress is where programming for WordPress leaves the back room:

As programming becomes more important, it will leave the back room and become a key skill and attribute of our top intellectual and social classes, just as reading and writing did in the past.

  1. I am not ashamed to admit that I’m finding that my career is increasingly influenced by following the observations of Tony Hirst. Some people are so-called ‘thought-leaders’. I am not one of them and that is fine by me. I was talking to Richard Davis about this recently and, in mutual agreement, he quoted Mario Vargas Llosa, who wrote: “There are men whose only mission is to serve as intermediaries to others; one crosses them like bridges, and one goes further.” That’ll do me. []
  2. Note that themes are not necessarily a superficial makeover of a WordPress site. Like plugins, they have access to a rich and extensible set of functions. []
  3. I am thinking of taking the idea of WordPress as a window on web technology further and am tentatively planning on designing such a course with online journalism lecturer, Bernie Russell. It would be a boot camp for professional journalists wanting (needing…?) to understand the web as a public space and we would start with and keep returning to WordPress as a mainstream expression of various web technologies and standards. []

These days are full

I am conscious that it’s been almost a month since I last wrote here but that is largely due to my work on other projects, websites and blogs.  Here’s an overview of some of the work I’m currently involved in. If you’re working on similar projects or want to discuss or collaborate on any of this, do get in touch.

The Learning Lab

I recently wrote a brief summary of the work I’ve been doing under the ‘Learning Lab’ banner, since I started my work as Technology Officer in the Centre for Educational Research and Development. WordPressMU occupied a large chunk of my summer, though I feel I have a good understanding of it now and can relax a little while supporting staff and students who wish to use it. It will soon be moving to the new, permanent home of http://blogs.lincoln.ac.uk

One of the unexpected outcomes of working on WordPressMU was the realisation that not only training but a different model of support is key to sustaining and improving the use of blogs and other Web 2.0 tools.  I’m keen to advocate and support the user-to-user support model that most open source and social web services develop rather than the traditional user-to-professional, ‘Help Desk’ model that exists for much of the software provided by the university. Models of user support are not something I’ve taken much of an interest in until recently, but the reality is that I alone am unable to support the growing adoption of WordPressMU at the university and I need to encourage staff and students to help themselves wherever possible.

Having said that, with colleagues in the Library and Research Office, I’m also planning to offer regular staff training sessions on the use of Web 2.0 tools in education and I’m visiting classes to give one hour introductions to WordPress, which is a good opportunity to work with and learn from both students and staff. In addition to this, I’m contributing towards the revision of policy documents which ensure that these new tools are used effectively and appropriately.

Lincoln Academic Commons

This is something I’m developing to promote and support the various initiatives at the university which provide Open Access to our research, teaching and learning. I started working for the university on a JISC-funded project to develop an institutional repository, having been working as an Archivist and Project Manager of a Digital Asset Management system in my previous job. Then, a few months ago, I heard about the difficulties people in the Lincoln Business School were having trying to establish a series of ‘Occasional Working Papers’ (OWPS) using existing portal software provided by the university. At the same time, I was looking at the Open Journal System for publishing Open Access journals, so I suggested that we set up the OWPS using OJS. Seeing what a great piece of software OJS is, I then suggested we use it for NEO, a planned journal of student research which we intend to launch in the Spring. Finally (and this is where it gets really interesting for me), Mike Neary, Dean of Teaching and Learning and Head of the Centre for Educational Research and Development, is advocating a more critical engagement with the debates about the marketisation of higher education through teaching practice. He’s calling this critical engagement, ‘Teaching in Public’, which encompasses the idea of an Academic Commons.

Professor Neary argues the uncertainty over the university’s mission requires the notion of ‘the public’ to be reconceptualized, so as to remake the university as an academic project that confronts the negative consequences of academic capitalism, and the commodification of everyday life. He will present Karl Marx’s concept of the ‘general intellect’ as an idea through which the university might be remade.

I contributed to a book chapter Mike has recently written which elaborates on this in more detail. You can read more about that on a previous blog post.

Access Grid

A project I’ve been leading for some months now is the installation of an Access Grid node at the university. We were fortunate in being approached by the Mental Health Research Network (MHRN) several months ago who offered to fund the installation of an AG node at the university to support their staff who work at the university and provide a facility that is otherwise missing in Lincolnshire. It’s been a really interesting and useful project for me as I learned about how the university undertakes a tendering exercise and I’ve been able to work with colleagues from across the university.  The node should be available to use sometime in January. The Access Grid project is yet another technology-based initiative at the university which further improves our research infrastructure and supports collaboration and the wider exchange of ideas among colleagues worldwide.

Anytime, Anywhere Computing

This is a new project that brings together three, originally separate proposals, that the ICT department and CERD were proposing to take forward. It covers:

  1. ubiquitous wireless networking
  2. so called ‘thin client’ technology as an alternative to desktop PCs and the management of software applications and resources
  3. access via user-owned devices, such as low-cost and increasingly popular ‘netbook’ hardware

We’re just starting to look at how we might offer the same user experience and services on our wireless network as we provide on our wired network. Currently the wireless network only offers Internet access. At the same time, we’re interested in evaluating new virtualisation technologies for the desktop. The ICT department are concluding a server consolidation project which is virtualising much of our server infrastructure. This brings many benefits and allows the ICT department to provide a more flexible service to users.  Our new study will look at whether similar virtualisation technology can bring benefits to desktop users, too. The third part of this project is based on a proposal I made a few months ago to evaluate the user experience and support issues that the new generation of ‘netbooks‘ introduces. Smaller screens, Linux operating systems, an emphasis on web-based applications and the rapid adoption of these low-cost devices often aimed at the education sector, require a better understanding of the impact of this technology and the influence it may have on driving students to use more and more web-based applications.

Are you working on similar initiatives? If so, please leave a comment and share your experiences.