LornaJane

I recently had reason to write a REST server in PHP, which was very interesting. There aren't a whole lot of resources on this topic around so I thought I'd write an outline of what I did. There is quite a lot to it so I'm publishing in multiple sections - this is part 1, which covers the central functionality and handling the incoming request.

Wrapping an Existing Class

The main functionality of the service was written in a class that had no awareness that it was a service - this is a similar approach to the one I described when I wrote about the PHP Soap Server - start with a normal functioning class and write some unit tests for it. The example I'm using today looks like this (my real version actually connects to the database and stuff but this is a nice mock of passing in a number and getting back an array):

In the soap article, you can see that wrapping a class takes just a few lines - for REST more code is required, but the idea is completely the same. In actual fact we started out with this as a soap service but then it was switched to rest - I only had to re-write the wrapper stuff and not any of the core functionality. Using the wrapper approach would also allow services to be published in multiple ways with the same underlying codebase.

Incoming Requests - Intialising the Wrapper

First of all I wrote a .htaccess file to direct all requests to the one controller file - so that all the different URLs would be handled in the same way.

As the requests came into here, I grabbed the data I needed and initialised the service class, something like this:

The variables are all read here and passed in to help decouple the systems - doing it this way allows us to initialise the Service with different incoming variables and/or a different library which can be really useful when testing, as it allows isolation of individual components. The syntax for getting the put and delete data is an interesting one, I wrote about this already in my post on accessing incoming PUT data from PHP, there are some helpful comments on that post as well.

To be continued ... later parts will cover the service itself and the response format used.

Yay! The PHPNW site is now online with all the details of the PHP North West Conference to be held on November 22nd, 2008 in Manchester, UK. The conference is specific to PHP and aims to develop the skills of the developers in the local area. Look out for local speakers, some drinking, and generally a good crowd. Put the date in your diary, tickets will go on sale soon.

We're also launching the call for papers for this event - it runs til 21st September and I'm really hoping we'll see some good entries covering a wide range of topics. We are including some shorter slots as well as the traditional 1-hour presentations, so hopefully you can think of something you'd like to talk about for one of those units of time.

If you've got any comments or questions about the event, the talks, submitting a paper or anything else PHP-north-west-y, then add a comment or drop me a line.

I'm wildly excited to be able to tell you that the PHP North West Conference now has a date and venue confirmed! The event will be at Manchester Central (apparently this used to be the GMex), on Saturday 22nd November with an early bird ticket price of £50. At the moment we have no website, no confirmed speakers, and no other information to release ... but rest assured there are lots of plans being worked on behind the scenes!! The site for the PHPNW user group and conference will be at http://phpnw.org.uk and there is a mailing list you can sign up to already.

The event is aimed at people working with, or wanting to work with, PHP in the north of England. We'll have a selection of sessions, with the technical content intended to be accessible to a whole range of audiences - it will also be multi-track so there's sure to be plenty of material to interest you, whatever your background. We will be having a call for papers for the sessions, and we're hoping that we'll get some good submissions - particularly from senior developers around the area and the wider UK. Whether you're hoping to speak, hoping to learn, looking for a good crowd to mingle with on a Saturday, or you just really like PHP geeks - put 22nd November in your diary and I hope I'll see you there!!

If you have any questions, comments or suggestions about this event, just let me know (I'm not organising the whole thing but I'm helping!), either by leaving a comment or by contacting me directly.

Recently I started writing a REST service. I began in the usual way, writing a php script, calling it with a GET request, accessing the variables using the PHP superglobal variable $_GET. I wrote code to handle a POST request and used the variables I found in $_POST. Then I tried to write a PUT request.

PHP doesn't have a built-in way to do this, and at first I was a little confused as to how I could reach this information. It turns out that this can be read from the incoming stream to PHP, php://input.

The above line provided me with a query string similar to what you might see on the URL with a GET request. key/value pairs separated by question marks. I was rescued from attempting to parse this monster with a regex by someone pointing out to me that parse_str() is intended for this purpose (seriously, I write a lot of PHP, I don't know how I miss these things but its always fun when I do "discover" them) - it takes a query string and parses out the variables. Look out for a major health warning on str_parse() - by default it will create all the variables all over your local scope!! Pass in the second parameter though and it will put them in there as an associatvive array instead - I'd strongly recommend this approach and I've used it here with my $post_vars variable.

This loads the variable $post_vars with the associative array of variables just like you'd expect to see from a GET request.

Simple Example

Its a bit of a contrived example but it shows use of the REQUEST_METHOD setting from the $_SERVER variable to figure out when we need to grab the post vars. Firstly, here's the script:


And here's what happened when I request the same script using two different HTTP verbs. I'm using cURL to show the example simply because I think it shows it best.

Via GET:


Via PUT:


Purists will tell me that I shouldn't be returning data from a PUT request, and they'd be right! But this does show how to access the incoming variables and detect which verb was being used. If you're going to write a REST service then the correct naming of resources and the correct response to each resource being accessed in various ways is really important, but its a story I'll save for another day. If you use this, or perhaps you access the variables another way, then do post a comment - there aren't a lot of resources available on this topic for PHP.

My employers, Ibuildings, have been running a series of seminars where we invite a few people (and it is a few, they are generally small events), bring some of our developers along, and have some technical tutorials, demonstrations and general discussions, and some food. The previous events have all been well-received and sound very civilised (and there's food, which is always good!)

I'm happy to announce that Ibuildings is venturing north of the Watford Gap - and the next event will be in Leeds, on the 9th September, the full details are at http://www.ibuildings.com/events/leeds. The main tutorial session will cover source control with Subversion, including advanced concepts such as merging and repository structures. We'll also look at deployment strategies for different types of software development processes and tools that can be helpful in this area. I'm delivering the main tutorial at this event, and if that wasn't enough incentive, I'm also bringing the nabaztag as my glamourous assistant!

We'll be running events in a lot of other areas of the UK as well, so if you can't make this one then watch out for more announcements or tell us where we should be running the next one! If you have any queries about any of these events then feel free to contact me, I hope I'll see some of you in Leeds in September.

So, at the Dutch PHP Conference, they were making a video and they interviewed me. The video is at http://www.bachelor-ict.nl/dpc and it is also featured in this article on DevZone which is exciting! The video is mostly about the PHPWomen organisation, rather than my talk but it does have some footage of me speaking and of the conference itself.