Why? 

Over the last few weeks i’ve moved over all my pictures from my php gallery to flickr, so now I really need to replace my hosted gallery with something better than a link to my flickr account. My solution to this was to create (what I think is) a nice little mashup of flickr hosted based pictures and a javascript visulisation of them. Rather than use one of the many flickr mashup’s out there I decided it was more fun to wrote my own…Simply i’ve taken 36 square thumbnails arranged in a 9×4 grid from flickr and used a combination of prototype, cube (with some modifications), lightbox2 with some javascript glue of my own to bind them together.

What does it do…

Well it’s easier to see it, but every second or two a randomly selected thumbnail in the 9×4 grid will rotate to a new picture from flickr and then this repeats forever. You can also click on any of the thumbnails in the grid to hightlight a picture and eventually i’ll provide a link to where that photo is hosted on flickr, once a figure out a better way to do it than to put the link into the title.

How’s it work…

Well i’m using a php script on my server to get a selection of photo details using phpFlickr; I decided to get 72 photo objects ever time I accessed to script, but on the initial load I display the first 36 onto the page. I used prototype to handle the Ajax request and json parsing, I guess I could I done this without prototype, but I couldn’t be bothered and it would have taken longer and lightbox2 requires it anyway! Then using a javascript image cube animation library I found this will animate a image rotation to a new picture from the remaining 36 pictures. Although I did have to modify the cube library a bit to use absolute positioning and setting some divs to be inline apart from the first thumbnail of the row. Once the page has runout of pictures from the initial server script load a new call is made to that script for another page of 72 picture objects from flickr … and so on … and so on … I also used lightbox2 to load up a larger version of the square thumbnail when you click on the thumbnail.

You didn’t take those pictures…

At the moment I’m just using the interesting pictures from flickr (they look better than mine), but once I fix the odd bug or few I’ll replace my hosted gallery to a nicer version of this mashup using my own pictures. Phew! PS Thanks firebug!

It’s taking a few weeks of cooking, but my Simple Storage Service is ready to come out of the oven to be eaten (and possibly spat out) by the world at large. Now there are still a couple of things on my TODO list, but nothing massive. Basically URL authentication of requests (needs some thought), postObject (I need to read the docs), virtual hosting of buckets (a lot of thought) and some tiny changes and bugs that i’ll fix over the next few days. So what has changed since my last post:

• Anonymous requests can now be made where permission to do so has been set.
• Authenticated/Alluser groups and ACL get and sets have been implemented.
• All REST calls have been implemented (except postObject)*
• Exception handling matches the S3 documentation (with some guess work)
• The REST layer was completely rewritten using test driven development
• phpDocumentator comments are being added to the code, so docs can be generated
• I’ve created a web form to help you create new users to the service

So what’s next …. ? I guess I’ll polish what’s been completed so far and add some documentation to make it simpler to deploy. And as i’m off Snow boarding from Saturday i’ll wait to see what sort of feedback I get before getting started on the SOAP section which should be easier now that I’ve got a good testing setup + looking for a new job as i’ll be leaving mine soon! I’ve also found that the most popular php client for S3 (from a google search) is missing some useful functionality, so i’m pondering re-writing it and making several optimizations so it can stream downloads from S3 etc etc…

The best use for this software, apart from academic curiosity and mocking is probably a failover/backup service incase S3 goes down (which it has done). This would work best if you are CNAME record to map to s3.amazonaws.com as I believe that as this is under your DNS control it is fairly trivial to map it to another host.

Other than that I’ll write a blog on how to set it up using xampp on windows and macports on a mac (when I MacBook Pro arrives)…

You can checkout the latest code from here: http://svn.magudia.com/s3server

* As this service hasn’t been developed to work to meet Amazon’s data consistency model I implemented getBucketLocation, but essentially it does nothing. Although in theory I could use MySQL clustering to implement this I’m not going to unless someone wants to pay me and I also don’t have a global server network to play with

phpAspects is a project to bring Aspect-oriented programming (AOP) to PHP. If you don’t know much about aspects then to state it very simply aspects is a way to separate concerns such as logging and dependencies like database handling to produce more manageable and maintainable code, but the wikipedia article on aspects can describe this better than I can!

Now this project isn’t really mature at the moment i.e. it’s alpha version 0.10 which means it’s very likely to change alot before it becomes final which is the main reason I’ve decided not to use it from my SimpleStorageService project - although I’m really tempted to play around with it anyway; The other reason why I’m not going to use it is because i’d have to add another PECL dependency to the project (on top of PDO) which is Parse_Tree (another alpha dependency… Hmmm!). Then again over the last few days I’ve come to believe if you want to write a REST interface on a LAMP style stack you’re going to need to be able to have server level access to configure Apache to allow PUT & DELETE HTTP verbs (editing httpd.conf), although I’m hoping to find a higher level solution to that problem for easier deployment.

But I do recommend that it’s a project you should keep your eye on as sooner or later you’re going to want to use Aspects to keep your code clean and simple. Once it is a bit more mature I will be using it in some or my more work related projects where I’ll have more control of which extensions are compiled into PHP.

I’m helping out a friend at the moment to include a forum into a charity site. The site is used by teachers and students as a educational resource and some of the resources are protected by your typical authentication system which uses the users email address as a username and a password of their choosing. Now none of this would normally set of any alarm bells, but adding a forum to this site brought a question.

 A typical forum uses a unique friendly name to identify users without exposing any contact information. If the only unique user identifier you have is a email address and you for very obvious reasons you don’t want teacher and students email addresses exposed then how do you resolve this?

In this case a solution was achievable although with caveats which I’m not going to go into right now, but in future when I (or you) design an authentication system it might do you good to at least consider how your user identifier is going to be used.

Before anyone says use OpenID I just don’t think it really would work in forums (yet); Although I know that you can have a nickname in OpenID it’s just too clunky a system at the moment to create a new persona for a new site for the average user (if your default nickname is already in use) i.e. it doesn’t pass my ‘Can my mum understand this?’ test!

Do I have a better solution - hell no, but i’m sure smarty people than me are thinking about it!

UPDATE: I found a excellent blog which articulates some of my concerns about OpenID

So after reading about the unscheduled downtime of Amazon S3 yesterday I thought that I should probably release what I’ve done so far. Although most of the work I’ve done has been focused on the storage layer and writing many many tests for it. So last night I spent a few hours hacking in functionality into what will be the REST layer of the service mostly from a PHP S3 Client to provide a very basic service to show what I’ve been doing - mostly handcrafted responses; although I’m probably going to the the pecl http extension to handle most of this in the future

This isn’t really up-to what I’d call alpha ‘quality’ in any respect, but it’s just a sneak peak with many many cavets i.e.

Anonymous authentication doesn’t work at all (you need an authenticated user for all method calls)

Only putBucket, deleteBucket, putObject, getObject, deleteObject have been partially implemented, although most methods are implemented at the storage layer.

Many many things need to be re-factored

Exception handling isn’t fully implemented yet

The REST layer has no tests and the SOAP layer hasn’t been started yet

You need the (PECL) PDO MySQL extension added to PHP (and probably some other PEAR libraries like Crypt/HMAC)

No documentation yet, but I’m willing to help with any questions

You need to be able to edit the httpd.conf for apache to enable PUT and DELETE http verbs*

If your running PHP as CGI then you may need to modify my .htaccess (well maybe?)

You need to create your own user using createUser in the storage class (but I’ll add a script into the subversion to help with this)

Security hasn’t been tested and the code is not optimized in any way

Plus some other stuff that I may have forgotten because I’m tired

You may have got the impression that I’m not entirely satisfied with this code yet and you’d be right. I’m only releasing this as *some* people *may* find it interesting. And one final thing, I don’t have a Amazon S3 account, I’ve basically cobbled this together from the documentation (which can be inconsistent), because I read the T&C’s and I wasn’t sure if Amazon would sue me if I agreed to them, so I didn’t!

Also you’ll need to create a mysql database, but the database details are hardcoded into the src/s3/lib/storage.php file and test/AbstractTest.php for unit tests.

So … blah, blah … it might not work … blah, blah … give me a break and i’ll help you ….. blah, blah …. I won’t be able to do any more work on this for one week before I start again … so here is the SVN URL ….

http://svn.magudia.com/s3server/

On the positive side of things, when I do get time next week to continue working on this project the hardest parts of the project have been thought about or have already completed, so implemented the REST and SOAP layers shouldn’t take along as I did implementing the storage layer.

* You need to modify your httpd.conf to allow PUT and DELETE http verbs by including these commands in your htdocs <DIRECTORY> tag (Apache doesn’t allow PUT or DELETE http verbs by default for sensible security reasons)

Script PUT /workspace/s3server/src/index.php

Script DELETE /workspace/s3server/src/index.php

Where the index.php matches where you (relative to your htdocs path) checked out the code.

So since my last post I’ve actually started to write my SimpleStorageService project and as I’m an agile developer I decided to write the project with the agile skills I’ve picked up over the last few years with Java, .net, scrum-master training et al and check out how easy it actually is to ‘do agile’ with PHP.

So…. where should I begin….

Unit Testing (Test Driven Development):

Firstly PHP has had unit testing for quite some time with PHPUnit; this is something which after using unit testing in Java and C# was actually quite straight forward and although there are other testing frameworks like SimpleTest I decided to go with PHPUnit as it seems more comprehensive; Although I found that SimpleTest has a better mocking implementation than PHPUnit, but for now I’m sticking with PHPUnit.

Also PHPUnit can integrate with Selenium and has a partial implementation of DbUnit, but that’s not complete yet - hopefully this will be complete by PHPUnit 4

Continuous Integration:

Now I didn’t think PHP had anything like this, so when I was looking into testing I found the phpUnderControl project which literally knocked my coding socks off as it’s a PHP wrapper for cruiseControl, but with a cool interface and extra PHP goodies on project code metrics, a Java like checkStyle which defaults to the PEAR coding standard and generating phpDoc as well as the normal cruiseControl stuff.

I was so impressed by this project that at the time (early January) I set it up on my macmini although I did have to use macports to replace the crippled default build of PHP that is bundled with OS X (please fix this Apple!). I initially installed version 0.20 of phpUnderControl, but I’m currently upgrading my install to the recently released version 0.30 which has a neat javascript metrics view - which is nice

Finally phpUnderControl neatly integrates with PHPUnit, which another reason why I’m using this and the project is now hosted alongside PHPUnit, so I hope to see more integration between the projects in the future.

Integrated Development Environment:

Allow this is by all means not needed to practise Agile, but a good IDE helps you write better code faster. I used to use DreamWeaver for all my PHP web development work, but as my SimpleStorageService is by definition a service project I didn’t need any HTML editing functionality. Anyway here was my IDE shortlist:

• DreamWeaver
• TextPad
• Eclipse (with PDT)
• Aptana (Eclipse based)
• Zend Studio Neon (now Zend Studio for Eclipse)

Ignoring DreamWeaver and TextPad as being out of date and inappropriate for the project I began with Eclipse (with PDT), but I quickly found several problems with this mainly SVN integration amongst other things. Then I gave Aptana a go which was beta at the time and did fix my SVN issues, but in the final version this was removed from the free edition (grrr!). So just when I thought that PHP didn’t have a good IDE literally stumbledupon Zend Studio Neon which ticked nearly every box I wanted from a IDE for PHP … PHPUnit, phpDoc, SVN, code coverage, code formatting, real time error checking, intellisense and much much more. The downsides are a bug where it doesn’t understand the PDO class when unit-testing (well it is beta!) and the final version isn’t free, so I’m using a time trial version which runs out in just over two weeks. Anyone want to buy me a copy

Source Control:

It still surprises me how many people don’t use or even understand the point of source-control, but I’ve been a big user for many years. Firstly with CVS and then once Subversion (SVN) was more stable I moved to that and didn’t look back. I know there are many other choices here, but as SVN is integrated into phpUnderControl and Zend Studio it was simply a no brainer. My DreamHost account includes SVN so all my code can be committed ‘off site’ and I can create an abstraction between my IDE and continuous integration environment.

Conclusion:

The state of Agile in PHP is good and much much better than it was even six months ago. I think once PHPUnit 4 is released, phpUnderControl reaches stablity and Eclipse with PDT catches up with Zend Studio (add unit testing, svn projects) then Agile in PHP should be excellent and easy to accomplish. One thing I haven’t looked at is if PHP has any good scrum management products (but I guess this doesn’t necessarily have to be in PHP).