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I just finished my presentation on the last day of the Xtech conference in Dublin. I’d chosen to ramble on about the advantages, problems and a few solutions of building applications atop of lots of APIs. The presentation is now up on slideshare at slideshare.net/garethr/design-strategies-for-a-distributed-web/.

Lots of interesting conversations have been occurring all week and a few people have mentioned a near barcamp feel at times. It’s a pretty small, clued-up, technical audience and as always some of the best bits have been conversations in the corridors.
Jeremy has been live blogging many of the talks which should be a worth a read later on. Although with three tracks most of the time that’s only some of the great talks on offer.

Popularity: 2%

Tagged Xtech

On departing pubstandards in London a few weeks ago Dirk Ginader said something along the lines of:

According to Dopplr you’ve spent 40 odd days in London in the last 8 months. Don’t you think you might as well just move here?

I’m not saying that had anything to do with it, but I’m happy to announce I’m moving to London in a permanent manner very very soon. I’m taking up a job at GCAP, working with quite a few people I know from various web goings on; Hi to Simon, Ross, Brad, Ed and Stuart amongst others.

Freelancing for the last year has been great. I’d been able to work on the variety of projects I’d wanted after leaving my previous job, and I’ve had more time to myself when I wanted to get involved with other projects. WaSP, SXSW, Highland Fling, BarCamp, Thinking Digital to name a few things I’ve been up to in the past 6 months. But something about working with a super smart team of people won me over. The fact that I’ll get to focus on Python and Django is an added bonus.

Patrick apparently closed the book on this happening some time ago. I’m just hoping someone got the date about right and won the money. I’m sure I’ll write more about the whole thing as time permits and lots of specific topics spring to mind. I have a number of events in the next month to get along to before all this happens however; if you’re along at Xtech, Thinking Digital, London Web Week, BarCamp NorthEast, BarCamp London 4 or @media then remember to say hi. My addiction to attending web events can only get worse with me being nearer London I fear.

Popularity: 6%

Build scripts. I think I’ve probably mentioned before; everyone knows they should but not many actually do. I’m not talking about your large in-house development teams or your sexy web startups; both probably have a good-enough build process for different reasons. But smaller teams, web design agencies or freelancers often rely on FTP and a prayer. One of the problems is definitely finding suitable documentation. It’s not that their isn’t a lot of good quality documentation – it’s the suitability of it for those with only a passing interest and a limited systems administration experience.

Capistrano is a tool for automating tasks on remote servers. It can be used for all sorts of useful things but we’ll concentrate on it’s utility for web site deployment. It’s been popular with the Rails crowd for a while and is written in Ruby, but it can be used for deploying sites in Python, PHP, Django, whatever you happen to be using at the time.

You’ll first need to install Ruby and Capistrano. The Capistrano site has installation instructions which should get you up and running. You’ll need to be able to use a console on your machine and have a passing acquaintance with your webserver. I’ve also assumed that you’re using source control, mainly because if you’re not you should start their. Automation becomes much more useful and practical on the back of a good source control system.

Right, lets get started. Create a file called capfile somewhere on your local machine. The following two code snippets should go in that file.

set :username, "<username>"
set :host, "<host>"
set :path, "<path>"
set :restart, "/etc/init.d/apache2 restart"
set :checkout, "svn export --force"
set :repo, "<repository address>"

Just replace the variables (marked with angle brackets) with your own values. The path is the full path on the remote server where you want to deploy your files to. Note that I’ve abstracted out the webserver restart command and the source control checkout command. The above example values assume you’re using apache and subversion (and want to do a subversion export). It should be easy enough to change these for your preferred combination of source control system and webserver.

desc "Remote checkout and restart of webserver"
task :deploy, :hosts => "#{username}@#{host}" do
  run "#{checkout} #{repo} #{path}; #{restart}"
end

If your platform of choice doesn’t require a server restart (say PHP) you can always remove the ; #{restart} portion of the command.

Now we’re all set up just bring up a console in the folder containing the capfile and run the following command:

cap deploy

After prompting for a password to access the remote machine this should display the output from the commands being run. Depending on the size of the repository you’re checking out

Of course for most projects you would want to expand this basic recipe. Maybe you have database updates to run or need to deploy to multiple machines at once? You’ll might have machine specific configuration files which aren’t in the source control system. You will also probably want to be able to revert back if something goes wrong and you might want to only change files that have been altered. Capistrano has lots of powerful features built in that will let you do just that, and once you get started with this sort of build scripting you’ll find lots of areas to improve. And you’ll find lots of good tutorials online that will take you further.

The difficult part with project automation and build scripts is often the getting started in the first place; especially if you’re not the server admin type. Unfortunately the documentation and articles written on the subject tend to be somewhat arcane and aimed at the more hardcore developer. Hopefully this simple, usable, example convinces someone else to give it a try.

Popularity: 6%

Tagged Python, Django, Ruby, apache, subversion, PHP, Capistrano

I often end up pondering URL design given a moment and something that keeps coming up is hackable search queries. But first a very quick primer on the idea of resourceful design.

REST is a series of architectural principals more than a defined architecture. The Resource Orientated Architecture builds on those ideas with a series of concrete guidelines put down by Sam Ruby for designing RESTful systems. The simple version is that you try to design your system around resources represented by URLs.

I’d thoroughly recommend reading RESTful web services whenever you get a moment as this subject is covered in detail.

Flickr isn’t a truly resourceful design but it does have many of the hallmarks. For example the URL that describes me is at:

http://flickr.com/people/garethr

When it comes to searching on flickr we have:

http://flickr.com/search/?w=all&q=pubstandards&m=text

The pattern of using a query string argument named q to pass a search string is pretty common. One of the guidelines mentioned as part of the ROA discussed query strings:

Query string parameters are appropriate if they are inputs to a Resource which is an algorithm. Otherwise, these values should be moved into the URI.

Search is definitely algorithmic. Now you could maybe argue that a global search should be done on the root of a site, with specific resource searches on the resource in questions. eg. /people/?q=. This would likely work fine but require some behind the scenes complexity as well as probably not being as obvious to the end user. Global searches are in many cases much more common that restricted searches and even in resourceful designs the root of the site (ie. the home page) might not act as a list of available site resources. A notable exception might would have to be the excellent BBC Programmes site which is basically one big semantic catalogue.

But we have another kind of URL that’s cropping up for search results, one that treats the URL much more like a fundamental part of the user interface for search. An example from a site I use all the time is The Accessible UK Train Timetable which allows for URLs like the following:

http://traintimes.org.uk/newcastle/london

You can basically squash all the search parameters from the form into the URL, meaning you can easily bookmark search results. Note however the actual content is likely to change. The above example for instance would use the current time to get a list of trains from Newcastle to London. In an hours time the results will be different.

Another good example would be the new Yahoo! UK TV listings which has URLs like these:

http://uk.tv.yahoo.com/listings/bbc-two/2008-04-17/

http://uk.tv.yahoo.com/listings/itv1/2008-04-17/21-00/

Again this is really a search query, or at least specifying the time and date is. In some ways it’s the return of the command line – allowing searches to be run very quickly from a textual interface.

Now, both these approaches treat URLs with the respect they deserve. But they do have the potential to clash somewhere in the middle if care isn’t taken. The Accessible Train Times site is a single purpose site which just does searches while BBC Programmes does feature a search engine but it’s just the global BBC search which takes you off site. And if that wasn’t enough potential competition then a question raised by Simon at The Highland Fling regarding URL design and the search engine optimisation crowd go me thinking too. From being a somewhat niche area of interest URLs might just become a sort after part of a good website design – fought over by the varying disciplines of modern web design and development.

Popularity: 10%

Tagged URL, design, REST, ROA

After my previous post about Django and the web standards community a number of the comments picked up on the fact I mentioned haml under the title Other Craziness. Ok, so I was being a little over-poetic but I decided this warranted a closer look.

Haml is a markup language that’s used to cleanly and simply describe the XHTML of any web document without the use of inline code. Haml functions as a replacement for inline page templating systems such as PHP, ASP, and ERB, the templating language used in most Ruby on Rails applications.

A quick example should help. The following haml code…

%div.special#primary Hello, World!

...is compiled to the following HTML:

<div class="special" id="primary">
  Hello, World!
</div>

Depending on your application this could be at runtime or as part of a build step. Although primarily associated with Rails because haml is also available as a command line utility you could in theory use it with any framework or language.

My initial take on this was to call haml an abstraction of HTML but Nathan Weizenbaum, one of haml’s developers, put me straight:

Haml doesn’t really abstract HTML. Not in the same sense that, say, Rails helpers do. Since Haml has a one-to-one mapping to HTML, I view it more as an alternate syntax for HTML than an abstraction.

Lots more examples for anyone interested can be found on the haml documentation site.

After some research and some playing around with the command line version of the haml engine I decided to see what Twitter thought about the situation. Little did I realise what I was letting myself in for:

Tom Morris kicked things off:

I’m not sure why everyone insists on clumsily reinventing HTML every few weeks (eg. wiki syntaxes, of which there are hundreds)

Brad Wright thought:

Sass is just stupid, since you’re basically writing exactly the same CSS just in shitty YAML style.

And followed with:

What’s the point of abstracting HTML? It’s not that hard

And Mark Norman Francis chipped in with:

EVIL. And not in a good, kittenish way.

A few people echoed Ross Bruniges sentiment that haml and sass are just:

front-end code for those who don’t really care all that much about it and would rather create databases

I have to admit to this being my initial reaction on hearing about and looking at haml, hence the remark from the previous post. But that’s not to say everyone was negative.

Mike Stenhouse stepped in and said:

Love haml – it’s all I use these days. More readable, dynamic and hackable. Took me a while to come around to it though…

Some of the comments were about how the use of haml might alter the dynamic of a team, to either positive or negative effect – depending on your point of view.

Mark Ng saw it as a cunning way of getting rid of the front-end guy.

at first, they look elegant. Then it becomes obvious how they remove designers from the process of making markup.

Where as Olly Hodgson say it maybe as a route to get the dyed in the wool back-end writing decent markup.

They look interesting. With proper training it might be a good way to get back-end programmers creating decent HTML (shock horror!)

At present haml is very much pitched at the Rails community from whence it came. Many of the examples demonstrate benefits compared to ERB, and haml is of course written in Ruby and available as a Rails plugin. Being perceived as part of that community has obvious benefits but also some subtle costs, in particular regarding those people that don’t like Rails very much.

I’m not really convinced of the benefits in all fairness. The something else to learn barrier only gets magnified when working within a team environment. You now have to train new recruits of whatever skill level in another syntax. One that they might be able to write quickly enough but can they understand from the briefest of glances at a template? HTML might not be great here but it is familiar to everyone. Their is also the programmers abstraction. What if I can’t get the markup I want out the other side of the black box? Yes it’s open source so I can hack the box open but that causes even more problems. And while I quite like meaningful whitespace (for instance in Python), in templates which fail if it’s not quite right I see a major problem for those whom a text editor is not their best friend.

I am however interested to see whether the problems people have with haml are with haml in particular or with the overall approach of alternative syntax’s for HTML and CSS. Are DSLs (Domain Specific Languages) needed for CSS and HTML? and if so is this a possible avenue for innovation on top of slow moving standards?

Popularity: 12%

Tagged haml, ERB, Rails, DSL, CSS, HTML