Paul Rouke and PRWD on User Centered Design

It’s confirmed, the North West’s first PHP conference is to be held at Manchester Central on the 22nd of November!

This is a hugely exciting event which should be a great day for PHP developers to listen, learn and discuss many interesting topics with each other.  After the success of the initial social gathering, it’s great to see the final announcement.

There’s currently a call for papers underway, giving potential authors a month to submit their presentation abstracts.  I see from Twitter that Jonathan Wage (lead developer of the Doctrine ORM library, which we have used here at PRWD) has put in a proposal and I’d certainly look forward to hearing what he has to say, with the launch of Doctrine 1.0 set to happen shortly before the conference.

Needless to say, I’ll be attending and I hope that as many others do so too.  I expect that PHPNW will become a regular and important fixture in the development conference calendar.

Further Information

The conference website is here, PHPNW Google Group is here, and an Upcoming.org event for the conference is here.

Following my earlier posts on Zend Framework and Symfony, the final part of my comparison will be an evaluation of Kohana.

Kohana is the newest of the three frameworks, appearing in May 2007 (albeit under a different name). However, Kohana began life as a fork of the CodeIgniter framework. The Kohana developers wanted to take the framework in a new direction, adding support for PHP 5 amongst other things. Now, over a year later, relatively little of the original CI code remains in Kohana.

Features

Having already written two posts about the feature-sets of MVC frameworks, I find that there’s not a lot new to say.  The usual features are in place: Kohana provides a default front controller which dispatches requests to methods of a controller class, located via routing rules.  Unlike Symfony’s YAML approach or Zend Framework’s .ini files, Kohana’s configuration files are all PHP-based, which adds some flexibility.

One particularly nice feature of Kohana’s configuration system is the ‘overriding’ of system-level defaults by application-level replacements.  The Kohana file-system is structured as follows:

<root>
  application/
    config/
    controllers/
    models/
    views/
    ....
  modules/
  system/
    config/
    controllers/
    models/
    views/
    ....

I’ve skipped out some directories from this file structure - the important point is that the structure of the ’system’ tree - which contains the core Kohana files - matches that of the ‘application’ tree.  This provides a useful concept for thinking about your application: it’s all about extending Kohana to do what you want.  A parallel can be drawn with Drupal’s module system, where modules in the ’sites/*/modules’ directory override those in the ‘modules’ directory, and so on.  In many respects, this doesn’t offer any particular advantage over any other approach, but I found that it helped my conceptual thinking.

This ‘override’ approach applies to all files in the application tree, from config files to controllers and views.  The system config files provide sensible defaults, but if you want to change them it’s easy.  Just copy the config file from the system directory to the app directory and start editing.  That the config files are in PHP is especially refreshing - no .ini files, no YAML and (praise be!) no XML!  Although some might argue that this detracts from readability, I disagree: not having to do a mental context-switch to go from reading YAML to reading PHP saves a lot of time and reduces the likelihood of error.

Taking the ‘override’ approach even further is the concept of ‘hooks’ and ‘events’. These will be familiar to many developers coming from other backgrounds; essentially, Kohana allows you to perform actions when events occur within the system. The core system provides some basic events (’startup’, ‘load controller’ and so forth) which can be handled by your own code. There’s nothing particularly revolutionary about this, but Kohana makes it easy to, for example, perform an action each time a page is displayed simply by writing a function and registering it as an event handler. No object-oriented inheritance voodoo, just a simple system that works.

Documentation

Kohana’s core code is readable, generally well-commented and using a good coding style.  And it’s a good thing too, because any Kohana developer will probably find themselves referring back to the source code quite often, owing to the relative lack of documentation.  There’s a valiant effort at creating some Kohana tutorials underway, but there’s a long way to go before Kohana’s docs can compare to Symfony’s. From a developer’s perspective, this makes using Kohana fun; it’s obvious that the developers haven’t made any particularly stupid blunders in designing the software and have succeeded in producing a very nice, elegant codebase. But there can be frustratingly few good examples of its use around, and the ‘community, not company-driven’ ethos can leave Kohana’s documentation and support materials looking a little unpolished compared to others.

Community

Kohana’s community looks strong and enthusiastic, driven by a genuine desire on the part of the participants to build a genuinely good framework. It’s hard to explain this in detail, but it’s possible to sense the desire of the developers to create something that is, in its own way, a work of code-as-art. The Kohana community is, of course, only a little over a year old. There isn’t yet a major book on Kohana and there are relatively few blogs about it. But there’s enough action at the core to suggest that Kohana can be sustained for the long term.

Conclusion

Kohana has much to recommend it. It’s evidently well-coded, with plenty of intelligent ideas behind its design, and a vibrant community. But, on the down-side, the documentation is severely lacking and many of the ‘jump-start’ features of other frameworks - say, basic CRUD code generation - aren’t present. This adds a little steepness to the learning curve, although I have to admit that I really enjoyed getting my hands dirty with Kohana. One regret is that there seems to be no central repository for Kohana modules (equivalent of plugins in Symfony). Being able to grab some ready-made modules to solve common problems would be nice.

My overall sense of that Kohana is that it probably will be the best PHP framework at some point in the future. It’s clear that what the Kohana community is building is something big and ambitious that might, one day, be the best way of rapidly developing PHP applications. But the shortcomings can’t be ignored: lack of documentation and lack of modules mean that there are other frameworks that can get the same job done faster. If you’re embarking on a long-term project and are not scared of using the code and comments as your primary documentation, Kohana is a great choice.

I’ve been meaning to blog about this sooner, but there’s no time like the present.  Recently the first meeting of the PHPNW (PHP North-West) user group was held, at the 235 Casino in Manchester.

For a first meetup, the attendance was excellent - over 30 people from the local PHP and web development scene. There were some familiar faces, from GeekUp and other similar groups, but also plenty of new people who I had never met before. The conversations were interesting and we were all helped along by a free round of drinks and, later, free pizza courtesy of Jenny Dunphy and her employers (thanks Jenny!).

There was a great buzz and lots of energy around the group, in large part due to the excitement at the upcoming PHPNW08 conference.  Final dates and venue details are to be confirmed (soon!), but there is a huge potential for a ground-breaking conference right here in the North West of England.  The PHP development community has changed a lot in the last couple of years, becoming more professional in outlook and spreading into new and more interesting areas of development.  The fact that there have been many interesting PHP conferences around the world proves this, and it’s about time that the vibrant NW web development sector put on its own show.

The main driver behind the idea of such a conference is Jeremy Coates, and he deserves huge credit for getting people together behind this idea and making it all happen.  There’s still a long way to go, but he has certainly managed to pull a lot of talented people into the operation, giving it every chance of success.

From my point of view, I’m greatly looking forward to more opportunities to network with other people in the PHP and web development industry locally, and the chance to listen and speak to some of the leading figures in our industry at the conference.  Adoption of PHP and similar technologies to tackle big IT and web projects is increasing all the time, and conferences like this are essential for promoting the practices and ideas that are needed to make this work, as well as the social network of companies, developers, entrepreneurs and managers whose collaborations are vital to the future of new business in the North West.

This post is the second in a series. The first post focussed on the strengths and weaknesses of the Zend Framework. This post about another leading PHP framework, Symfony.

Note: This post refers to Symfony 1.0. Version 1.1 has recently been released, but I have not had time to examine it in detail, though I imagine that most of my comments here apply equally to the new version.

Superficially, Symfony reminds me of Django. This is a Good Thing in my book. Symfony is a framework that is clearly designed to get applications up and running quickly, with a good ORM system and the facility to generate basic code automatically. The contrast with ZF is quite clear: Symfony is a tool that makes building web applications quick and easy as a top priority.

Features

Symfony provides all of the things that one would expect from a modern web framework, and a few more besides. The MVC components are all there – model development is supported by an ORM system that uses the Propel library, although there’s nothing to stop you using another library, such as Doctrine, instead (in fact, this is quite commonplace, and there is a well-supported plugin for Symfony that does just that). The controllers (’actions’ in Symfony parlance) are supported via a base class that provides useful abstractions over the HTTP request/response process. Views are rendered automatically for successful actions, with ‘partial’ views allowing sub-elements of a view to be templated, and ‘components’ fill a gap between heavyweight action-view combinations to provide ‘widgets’ which can be reused in different views throughout your app. Various helper functions save time and code by generating common HTML elements for you.

A lot of time spent on small Symfony projects will be spent editing configuration files as much as writing code. Some people might not like this, but I found it to be inrcredibly useful. Form validation, for example, can be set up using configuration files (although you can extend the basic set of validation options using custom classes). More importantly, your data model is defined using a configuration file which specifies your tables, their contents, and the relations between them. Once you have created your schema file, you can run command-line scripts to auto-generate the PHP class files that form the basis of your model. For example, for a table called ‘Posts’, Symfony (or, more accurately, the Propel library) will generate a PHP class called ‘Post’ which you can edit yourself, but this class inherits from the class ‘BasePost’ which provides getter/setter functions for the fields, as well as functions to retrieve related objects. Also created is the PostPeer class which provides (mostly static) functions to retrieve Post objects from the database. From here, you can run further commands which will generate basic CRUD modules – you can actually have a functional data-entry app without writing a single line of code. It will rarely be useful for production purposes out-of-the-box, but it provides a good foundation to build from.

There are plenty more configuration files, controlling database connections, caching, routing (URL paths), logging, security (access control) and default view settings, amongst other things. This approach won’t be to everyone’s tastes, but I have to admit that I liked it. One wrinkle is that many of these configuration files are in YAML format – a kind of strange hybrid of INI files, XML and Python’s whitespace handling that has been used in the Ruby on Rails. Again, it’s a matter of personal taste, but I found these files to be more readable than XML and certainly a lot less typing is involved in editing them.

Documentation

The documentation for Symfony is awesome. It is, quite simply, the best set of free documentation I have ever read for any software library, ever. The documentation on symfony-project.org consists largely of three main parts: The Book, the API reference, and Askeet. The Book, as the name suggests, consists largely of the content which makes up The Definitive Guide to Symfony, by Fabien Potençier (CEO and lead developer at Sensio Labs, where Symfony was created) and Francois Zaninotto, until recently the head of the Symfony documentation team. The Book is an invaluable reference to the core features of Symfony, and provides all of the introduction that anyone could need. The API reference provides a comprehensive backup for when you need the precise details, although it could be slightly easier to navigate. And, as if all of that were not enough, there’s ‘Askeet’, a 24-part mega-tutorial, in which Symfony is used to create a whole, functioning web 2.0 app, in easy-to-follow stages. Each stage represents a new achievement, with an emphasis on getting a new working piece of functionality in place. Often, code from earlier stages is substantially refactored during later ones, providing a good example of how to go about transforming a prototype into a final application. The bottom line: Symfony’s documentation rocks.

Community

Symfony’s community is not huge, but does seem to be fairly active. Symfony seems to follow the ‘benevolent dictatorship’ model of open source development, as exemplified by Linus Torvalds‘ leadership of Linux or, in the PHP realm, Dries Buytaert’s leadership of the Drupal project. Fabien Potençier appears to be the overall head of the Symfony project, although there are other major contributors. Symfony seems to have a particularly strong set of plugins – code modules which extend or enhance the framework, or provide substantial units of functionality which can be plugged in to Symfony apps. There certainly aren’t as many Symfony plugins as there are, say, Drupal modules, but this is a strength that does not seem to be present in many other PHP frameworks. The community is also active in contributing documentation, with Andréia Bohner’s Symfony cheat sheets being a shining example.

Conclusion

I have to admit, I’m now something of a fan of Symfony. There is a streak of common sense running through the way it works which makes it very fun to work with. The documentation is fantastic, and the community looks strong enough to support development for the long term. The only dark cloud on the horizon is the fact that questions have been raised by some long-standing community members about the direction that the newly-released version 1.1 is going in, suggesting that it may be sacrificing some simplicity and ease of development for a slightly more ‘purist’ approach to code structure. Time will tell whether or not these fears are well-founded but, for now, I think that Symfony is worthy of recommendation.

I have recently been researching various PHP frameworks, for use in upcoming projects.  These projects are large-scale, enterprise PHP systems which are going to be developed and maintained over a long period of time, so making the right choice of framework is crucial.  Also important is the ease of development – how easy the different frameworks make application development, and how they support rapid development, prototyping and agile development processes.  This post is the first in a series comparing the strengths and weakness of PHP frameworks.

The first two frameworks I have considered are the Zend Framework (currently at version 1.5) and Symfony (version 1.0, though version 1.1 has just been released).  I have considered a number of different factors and my judgements are very much a subjective view.  I have had plenty of experience of different software libraries, from coding C++ using the Microsoft Foundation Classes library in the late 90s, to PHP using the Drupal CMS/F (whether one considers Drupal to be a ‘framework’ is a matter of debate) and Python using Django.  In this time I think that I have learned to spot the strengths and weaknesses of frameworks and libraries, so, although subjective, my views aren’t totally uneducated.

Zend Framework

The first thing to say about ZF is that it wasn’t what I expected.  Having used Django and observed the general trend in web frameworks towards code generation and advanced ORM, ZF was surprising in that it bucked this trend entirely.  If you want CRUD code with ZF, you can write it yourself.  This, in itself, is not necessarily a bad thing, but it is slightly discouraging when you just want to get in and have a play about it with the framework.  In this day and age, the ability to rapidly assemble a working prototype is very important, and ZF could go further in making this easy.

Features

After a while of using ZF, it becomes apparent that my initial objection – that it doesn’t really speed up development during the very early phase of a project – is an intentional design choice.  The ZF developers refer to this as ‘use-at-will’ architecture; in old-fashioned software engineering lingo, we might say that ZF is ‘loosely-coupled’, in that the various classes it provides can be used separately, without reference to the rest of the framework.  This makes ZF a great choice for refactoring legacy code, as you can just plug in those bits of the framework that you need, without having to modify anything else.  If all you really want is the (very useful) ZF Akismet class (which interfaces with Automattic’s Akismet service), you don’t need to use the rest of the library at all.

In fact, after a while I started to think that the aims of ZF are actually somewhat different to the aims of other frameworks.  Most other PHP frameworks were funded and contributed to by developers who needed the functionality in their day jobs.  CodeIgniter came from the development of ExpressionEngine, Fabien Potencier’s Sensio Labs created Symfony to power their in-house projects, Drupal was started by Dries Buytaert to provide a basic community website and forum and Ruby on Rails began life as a basic library of functions used by 37 Signals for the development of Basecamp.  The Zend Framework, on the other hand, was funded by Zend specifically to create a strong, reliable PHP framework in order to give PHP a rival to Rails and Django.  It is, in effect, an ‘immaculately conceived’ framework, designed from first principles to support the widest-possible deployment, rather than to solve specific common problems.

In this respect, ZF is more of a ‘library’ than a ‘framework’.  It provides a set of classes that you can use as you see fit, taking out the ones that interest you, and leaving the rest.  What it does not really do is provide you with the basic foundational structure of an app that most other web development frameworks tend to do these days.  This is probably due to Zend’s different motivations in creating ZF – they are not a bunch of deadline-driven web developers trying to make their own jobs easier by creating a framework to build new apps with; instead they are attempting to create a set of classes that others can use in a whole variety of different ways, many of which the ZF developers cannot anticipate.

As such, ZF represents something similar to the C++ Standard Template Library – the object-oriented successor of the older C Standard Library.  Zend appear to be trying to give developers a new set of modern, object-oriented tools with which to build applications, perhaps replacing some of the reliance on the huge legacy PHP feature set.

Documentation

ZF’s documentation is poor.  There’s a reasonably good reference for each class, but there are nowhere near enough example applications and tutorials.  This is probably related to the fact that ZF classes can be used in isolation from each other and there isn’t always a clear way of constructing a basic app to make use of these classes, but this is no excuse.  For a developer considering ZF for the first time, it can be hard to see exactly how one is meant to make use of it.  What examples there are tend to be quite complex and focus on the arcana of the framework’s implementation than practical use cases.  This is my single biggest problem with ZF.

Community

The genesis of ZF also contributes to the slightly odd feel of the community.  Coming from a Drupal background, I’m used to a very self-reliant community, with a strong ‘do it yourself’ approach to improving the software, the kind of ethos that, to me, signifies a truly great open source development.  The Zend Framework doesn’t have that yet.  Too often, the ‘community’ seems to consist of ‘users’ rather than ‘doers’, people who would rather petition Zend to improve the software than submit a patch or create a new module.  Open source projects, if they work well, are a bit like crowd-surfing at a gig – you throw yourself out there and hope that enough people decide to catch you.  At the moment, it’s not apparent that there are enough people to catch the Zend Framework, so it can’t make the leap.  The developers can’t quite let go of their creation, either because they are unwilling to, or because there’s not enough people there to catch it.  This does lead to some unfortunate examples of developers reacting personally to criticism, rather than the standard open source response of ‘fix it yourself if you don’t like it!’.

Conclusion

ZF’s strengths are clear – the code is well-written, covers a range of common web development tasks, including some areas neglected by other frameworks, and succeeds in making it easy for developers to incorporate ZF code into legacy projects.  These strengths alone make it an important piece of software that is likely to remain relevant for cutting-edge PHP developers over the next few years.  The framework’s weaknesses – that it isn’t really a framework – are easily addressable; it’s not hard to imagine someone creating the additional ‘glue’ that would make ZF a viable framework in the mould of Rails and Django.  If that code came from the community rather than Zend, then it would be a sign of ZF blossoming into a truly useful framework.  And if this could all be documented, we might be getting somewhere!

Part two of this post will consider the Symfony framework. Stay tuned!