Of course, Zend Framework has an analogue to Symfony tasks in the Zend_Tool component's "providers". In this post, I'll demonstrate how you can create a simple provider that will return the most recent entry from an RSS or Atom feed.

The goal of this camp was to get the European PHP community leaders together and learn about the new products and new ideas Microsoft are working on. For those of you who read about the Microsoft web developer summit that took place in Redmond in December 2009 you might think it was the same thing however you would be utterly wrong.

While the camp in Redmond was very informative and we are learnt a great deal of new features coming up with Microsoft, it was vastly different than the JumpinCamp in Zurich where the focus of the camp was to get the developers to interact with the actual Microsoft developers instead of only learning about new features. The point of the JumpinCamp was to get your hands dirty in code so we all got a few hours of lectures, then sat down and worked on either implementing those solutions into our respective Open Source projects or even discussed and raised concerns we might have regarding some of their products.

I thought it might be nice to share some of the projects I’ve started working on while I was over there and what I had interests in:

OData

After meeting with Claudio Caldato, the program manager for the Interoperability team, we went over the OData project and after looking at the position of OData and it’s potential, I decided to join the team and start by developing a PEAR package that will allow producers to publish valid OData Atom Pub feeds and serve as a base driver for the PHP community (Which could be easily ported to Zend Framework, Symfony, Lithium, etc.)

Obviously one of the reason for and OData producer package is to be able to make all the Frapi users potential OData producers. Moreover, as some of you know, sometimes I get into rants about web semantics and microformat. When I saw OData I realized that we could potentially bring some microformat standards within OData Atom Pub feeds (Or JSON Feeds).

Another thing that lit me up was the JSON feed. As some of you may have read on this very blog a few months ago I wrote an article about having something called PJSF which basically is the concept or idea of defining a standard format for JSON feeds. When I saw that OData has the ability to generate JSON feeds, I obviously jumped on the occasion of making a difference in the semantics world

Azure

Azure basically is a platform that offers a flexible, familiar environment for developers to create cloud applications and services. With Windows Azure, you can shorten your time to market and adapt as demand for your service grows.

What does is really mean? Azure is an all-in-one cloud solution. Even though the concepts are a bit arduous to grasp, we can all thank Josh Holmes and Maarten Balliauw for their essential presence at this camp to help us with all the questions we had and their thorough understanding of their baby (Azure).

Azure was another thing that sprung to my mind for Frapi. What if we could get our Frapi customers to be deployed directly into the cloud? Obviously it’s possible to hack around all the possible Amazon web services and to get somewhat arranged so our customers woul

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Load the feed

To load the feed, you need to create an new DOMDocument document using it's load() method. This works with the PHP stream wrappers, so you can load local files or urls. DOMdocument, has dedicated methos for XML strings and html files and strings, too.

$feed = new DOMDocument();
$feed->load('http://www.a-basketful-of-papayas.net/feeds/posts/default');
...


If here is any problem with the resource, PHP will output error messages. You can use libxml_use_internal_errors() to block them. With libxml_clear_errors() the internal error list is cleared, libxml_get_errors() returns them so you could implemented you own error handling. Just ignore them for now:

$errorSetting = libxml_use_internal_errors(TRUE);
$feed = new DOMDocument();
$feed->load('http://www.a-basketful-of-papayas.net/feeds/posts/default');
libxml_clear_errors();
libxml_use_internal_errors($errorSetting);
...


In the next step you should check if you got some content. I use the documentElement property for this. If it is not here, the feed has to be invalid because any XML needs at least one element node.

if (isset($feed->documentElement)) {
  ...
} else {
  echo 'Invalid feed.';
}


Initialize XPath

Now a XPath object is needed to execute expressions. Atom feeds make use of namespaces, often declaring the atom namespace as default. But in XPath you have no default namespace, you need to register the namespace with an arbitrary prefix. It does not have to be the same prefix used in the XML file. It can't for the default namespace obviously because it has no prefix in the XML file.

...
$xpath = new DOMXPath($feed);
$xpath->registerNamespace('atom', 'http://www.w3.org/2005/Atom');
...


If you load html into the DOMDocument using the special methods, all namespaces are ignored. You can skip the registration in this case.

Executing XPath Expressions

The DOMXPath object has two methods for executing xpath expressions. One is query(), it always returns a DOMNodelist. You should use the second one: evaluate(). It will return DOMNodelist objects by default, but depending on the expression it can return other types, too. With evaluate() you have direct access to the title text, it will return an empty string if the feed has no title.

The code selects the element nodes in the registered namespace and casts them to string.

...
echo $xpath->evaluate('string(/atom:feed/atom:title)'), "\n";
echo $xpath->evaluate('string(/atom:feed/atom:subtitle)'), "\n";
...


Next we will loop over all entries. A DOMNodelist works with foreach, the expression will return an empty list if it does not match, so no additional checking is needed. Inside the loop the entry node is used as a context argument for evaluate().

...
foreach ($xpath->evaluate('//atom:entry') as $entryNode) {
  echo $xpath->evaluate('string(atom:title)', $entryNode), "\n";
  echo $xpath->evaluate(
    'string(atom:link[@rel="alternate" and @type="text/html"][1]/@href)',
    $entryNode
    ), "\n";
  echo "\n";
}
...


Conditions

XPath expression can be conditions. It can be used to check if a entry has categories (tags). The return value of the following expression is a boolean value.

... if ($xpath->evaluate('count(atom:category) > 0', $entryNode)) { ... } ...

Loop over attributes

Each entry can have several categories. The title of the category is in it's attribute "term". You can select these attributes directly into a list.

echo 'Categories: ';
foreach ($xpath->evaluate('atom:category/@term', $entryNode) as $index => $categoryAttribute) {
  if ($index > 0) {
    echo ', ';
  }
  echo $categoryAttribute->value;
}
echo "\n";


Complete Example

Here is the full script. Be aware that it outputs text. If you execute it using a webserver (and not the command line), you should add a header('Content-Type: text/plain') to the top.

<?php
$errorSetting = libxml_use_internal_errors(TRUE);
$feed = new DOMDocument();
$feed->load('http://www.a-basketful-of-papayas.net/feeds/posts/default');
libxml_clear_errors();
libxml_use_internal_errors($erro

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A PEAR channel server allows you to install PEAR packages with the PEAR command line. You are probably already familiar with it as it comes bundled with most PHP installations:

$ pear install ...

Pirum comes from my frustration with the current state of PEAR channel servers. Beside big Open-Source projects like symfony, I'm also responsible for smaller projects (like Twig, or Swift Mailer). But for all my software, I like to provide different way of installing them: directly from SVN via svn:externals, from my Git mirrors, from an archive to download, or with the PEAR command line.

Except for the PEAR package installation, the other ones are quite easy to setup and automate. But providing a PEAR channel proves to be more involving. The only serious PEAR channel server I'm aware of is Chiara_PEAR_Channel from Greg Beaver. This is the software I used for symfony for four years. It works really well, but is a bit cumbersome to setup for smaller projects (it needs a database, and you need to configure some categories, the contributors for the project, and more). That's fine for PEAR itself, but frankly, for the rest of us, that's just too much.

As a matter of fact, hosting a PEAR channel server is super simple. It's all about static files. That's right, even if you need some sort of PHP scripts to maintain a PEAR channel server, the frontend used by the PEAR command line tool can only be static files (mainly XML ones). And Chiara_PEAR_Server works exactly like this. The backend, done in PHP, is where you maintain your packages, and it generates the frontend, a bunch of static files for the frontend. That's a really great architecture as it allows to scale very easily. For instance, you should probably be able to host a PEAR channel server on a CDN line Amazon S3 in a matter of minutes.

Thanks to this decoupled and simple architecture, I wrote some PHP scripts to manage a PEAR channel server for the symfony plugins two years ago.

The idea for Pirum came when I started the Twig project. Obviously, I wanted a PEAR channel server for Twig, but I really did not want to use Chiara_PEAR_Server. So I started to hack my own and Pirum was born.

Pirum lets you setup PEAR channel servers in a matter of minutes. Pirum is best suited when you want to create small PEAR channels for a few packages written by a few developers.

Pirum consists of just one file, a command line tool, written in PHP. There is no external dependencies, no not need for a database, no need to setup credentials, and nothing need to be installed or configured.

Installing Pirum is as simple as downloading the pirum file and saving it where you see fit.

Of course, Pirum itself uses Pirum to provide a PEAR channel server for itself!

Even if Pirum only consists of just one file, it comes with a lot of great features:

Besides its size and simplicity, Pirum is packed with a lot of features:

• It creates a full-featured PEAR channel server useable by any PEAR CLI;

• Each channel has an html page describing the server and the packages it hosts;

• New releases can be tracked by subscribing to an Atom feed.

Of course, it also comes with some limitations:

• No support for fallback PEAR channel servers;

• No category management (all packages are under a "default" category);

• No web interface for managing the packages.

You can find more information about using Pirum on its official website.

Pirum is already used by the following Open-Source projects:

• Symfony

• PHPUnit

• Swift Mailer

• Twig

• FluentDOM

• Pirum

I hope that with Pirum, more Open-Source projects will start providing a PEAR channel as a mean to install their software. If you start using Pirum for your project, please send me an email so that I can update the list on the Pirum website.

I think the next thing you should cover is how to retrieve put parameters and maybe even attempt to start a discussion on the different school of thoughts about POST vs PUT (Especially in the PHP world).

I know I’m even guilty of mentioning different schools of thought on POST vs. PUT in my talks, but the truth is that REST doesn’t specify what to use for what actions. These are defined by HTTP and not by REST.

Roy Fielding has this to say about the use of HTTP verbs in RESTful applications:

Some people think that REST suggests not to use POST for updates. Search my dissertation and you won’t find any mention of CRUD or POST. The only mention of PUT is in regard to HTTP’s lack of write-back caching. The main reason for my lack of specificity is because the methods defined by HTTP are part of the Web’s architecture definition, not the REST architectural style. Specific method definitions (aside from the retrieval:resource duality of GET) simply don’t matter to the REST architectural style, so it is difficult to have a style discussion about them. The only thing REST requires of methods is that they be uniformly defined for all resources (i.e., so that intermediaries don’t have to know the resource type in order to understand the meaning of the request). As long as the method is being used according to its own definition, REST doesn’t have much to say about it.

The POST vs. PUT debate, however, does rage on in different communities, and some protocols have defined their usage. For example, the Atom Publishing Protocol (RFC 5023) explicitly states in section 4.3 that “POST is used to create” and “PUT is used to edit.”

The important thing to note is that REST doesn’t care how the HTTP verbs are used, as long as they are used properly according to how they are defined in the protocol you are using.

For those interested, HTTP (RFC 2616) defines POST by saying:

The POST method is used to request that the origin server accept the entity enclosed in the request as a new subordinate of the resource identified by the Request-URI in the Request-Line. […] The actual function performed by the POST method is determined by the server and is usually dependent on the Request-URI. The posted entity is subordinate to that URI in the same way that a file is subordinate to a directory containing it, a news article is subordinate to a newsgroup to which it is posted, or a record is subordinate to a database.

PUT is defined as:

The PUT method requests that the enclosed entity be stored under the supplied Request-URI. If the Request-URI refers to an already existing resource, the enclosed entity SHOULD be considered as a modified version of the one residing on the origin server. If the Request-URI does not point to an existing resource, and that URI is capable of being defined as a new resource by the requesting user agent, the origin server can create the resource with that URI.

With this line of thinking, you might come to the conclusion that POST is used for creation of a subordinate resource, while PUT could be used for both creation or modification of a resource. The important distinction is that POST identifies the resource for which the entity should be considered a subordinate; PUT does not.

What is Asynchronous Processing?

What Problems Does Asynchronous Processing Solve?

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1. Cheap and cheerful desktop machines w/ multiple monitors and plenty of RAM, normally with AMD CPUs. These machines mostly run some form of Linux … Ubuntu and Debian are both popular.
2. Various laptops, a fair mix of MacBook Pros and other kit running Linux.
3. Virtual machines running on the desktops and laptops, used for cross-browser testing.
4. Virtual machines running on HP servers and blades, used for system testing, release testing and production.

It gives us a lot of flexibility, allows us to develop and test on standards-compliant environments (but still use Windows for testing IE), and most of the time the developer is the bottleneck not the equipment Recently, I’ve added both a netbook and an Atom-based mini-itx machine into the mix, and this blog post is my attempt to recommend that you consider doing the same.

Netbooks are incredibly popular in the wider computer-owning population. Over here in the UK, they come free with many mobile broadband packages, making them cheaper than many low-end laptops. They’re sold in the supermarket and the high street. Their small form factor and relative lightweight makes them appealing to people who would never willingly cart a traditional laptop around. And they run Windows, which most people are familiar with.

After an initial explosion of innovation, the specs have settled around a 1.6GHz Atom processor, 1 GB of RAM and a 10″ 1024×600 resolution screen. That’s not a lot of power, and it isn’t a lot of screen estate. How do your websites look on a netbook? Does your home page or your landing pages make an impact at that size, or is your site’s message partially or completely below the fold? How do the rest of the pages look? If you’re creating an app, does the user have enough of a working area to comfortably do their tasks? Try using Google Reader or Zimbra on a netbook to see examples of what to avoid.

And how do your websites run on a netbook? Too much Javascript, and the pages won’t be snappy. The CPU won’t keep up, and the different latencies and throughput of mobile broadband make round-trips back to the server much more noticeable. Javascript that fires at regular intervals (e.g. rotating marketing spotlight images) can force the CPU to switch execution speeds, and so drain the netbook’s battery much quicker.

Testing on a netbook is one way you can spot and deal with these problems before your customers do.

Stuart is running a course in Manchester in October immediately before the PHPNW09 conference on how to setup and organise your PHP developers to ensure things run smoothly for you and your customers. Learn more about the course, or sign-up now.

A simple, open, server-to-server web-hook-based pubsub (publish/subscribe) protocol as an extension to Atom.

Parties (servers) speaking the PubSubHubbub protocol can get near-instant notifications (via webhook callbacks) when a topic (Atom URL) they're interested in is updated.

The protocol in a nutshell is as follows:

An Atom URL (a "topic")

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Day 0: Tutorial Day

Thursday, June 11 was tutorial day. A whole day dedicated at learning new things by the greatest PHP minds in the world.

I attended the "Zend Framework Workshop" by Matthew Weier O' Phinney, Chief Architect at Zend Framework.

I went to see this tutorial session to see all the goodies that are put in Zend Framework 1.8 and to learn how to do stuff better. Great stuff like Zend_Tool, Zend_Application and other Zend Framework components are worth checking out.

As it appears, I have to look into the Zend_Acl adapter using a configuration file or an external source and contribute my solutions to the Zend Framework wiki.

Afterwards a Belgian delegation went down-town Amsterdam to have dinner at an Italian place and a drink afterwards at "Leidse Plein".

Day 1

Day one was a very hectic day for me since I was scheduled to speak at 10:30am. But we'll get there in a minute.

Opening keynotes

Before the opening keynote of Cal Evans, Director of PCE at Ibuildings, an awesome animated movie was shown to the public.

Cal Evans talked about what everyone could expect at the conference, what the rules of engagement were and what tags to use during the conference (a very important note).

Andrei Zmievski opened the conference officially talking about "PHP: people, code and ideas". Too bad I had to flee the scene half way the presentation to set up my gear for my own talk about SPL.

Morning Sessions

I hosted a talk called "SPL, not a bridge too far" where I discussed on a low level (according to some, a bit too low) the funky features SPL brings to the table. And looking at the comments left on joind.in I actually got people interested in using SPL in their future development projects.
Too bad I cut it short, like most people mentioned, because there's a whole lot to tell about SPL. Thanks everyone for you feedback, I will definitely keep it mind to make my presentation better.

Ben Ramsey showed us that "Grokking the REST architectural style" is worth thinking about when dealing with REST web services. He also talked about ATOM as a protocol, and he really got me interested in it to find out more. Thanks Ben, it was awesome.

Afternoon Sessions

Matthew Weier O' Phinney impressed us all again with another talk about "Contribute" and what we developers could do to make a difference.
For everyone involved in open-source projects, a must see presentation and again lots of kudos to Matthew for bringing this point to the attention of the masses.

Unfortunately I missed Stefan Esser's talk about "Secure Programming with the Zen

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