Blog Posts

Phly Darcs Repository online

A darcs repository browser is now online for the Phly channel.

If you're not familiar with darcs, it's a revision control system, similar to GNU Arch and git; changes are kept as patch sets, and repositories are branched simply by checking them out. This makes darcs repositories very flexible, and incredibly easy to implement. Static binaries are available for most systems, which makes it easy to install on systems to which you have no administrator rights.

A perl CGI script is shipped with darcs, and provides a web-based repository viewer. It utilizes darcs' --xml-output switch to create XML, which is then transformed using XSLT. However, there are some issues with the script; it is somewhat difficult to customize, and makes many assumptions about your system (location of configuration files, repositories, etc.). To make it more flexible, I ported it to PHP, using Cgiapp2 and its XSLT template plugin and Phly_Config.

I have released this PHP darcs repository browser as Phly_Darcs, which contains both a Model and Controller, as well as example XSLT view templates. It is currently in beta as I'm still developing PHPUnit2 tests for some of the model functionality, as well as debating the ability to add write capabilities (to authenticated users only, of course).

Update: fixed links to internal pages to use absolute urls.

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Cgiapp2 2.0.0 FINAL Released

After several months of testing and some additional work, I've finally released the first stable version of Cgiapp2.

It is available at both the Cgiapp site as well as via my Phly PEAR channel.

There were a ton of changes while creating the Cgiapp2 branch. From the release notes:

The 2.x series of Cgiapp completes a PHP5 port of Cgiapp2. PHP5 compatibility changes include visibility operators for all properties and methods, declaration of many methods as static and/or final, and the use of exceptions for catching run mode errors. Most notably, though, is the fact that Cgiapp2 is now an abstract class, with one abstract method, setup(); this enforces the fact that you must subclass Cgiapp2 in order to create your application.

New features include:

  • Callback hook system. Cgiapp2 is now an observer subject, and has hooks at several locations within the application. Additionally, it provides a method for registering new hooks in your applications. The callback hook system replaces the plugin system introduced in Cgiapp 1.7.0.

  • Template engines are now relegated to plugin classes, and should implement the Cgiapp2_Plugin_Template_Interface. Shipped template engines include Smarty, Savant2, Savant3, and XSLT.

  • Improved and more extensive error handling, which has been expanded to exceptions as well. Cgiapp2_Exception and Cgiapp2_Error are both observable subjects, with interface classes for implementing observers. This allows the developer to tie into exceptions and errors and perform actions when triggered (Log and Mail observers are implemented for each).

  • Cgiapp2_FrontController class. This is a simple front controller that dispatches to public static methods in registered classes. Included is a 'page' controller for handling static pages.

I have included migration notes, for those migrating from the 1.x series of Cgiapp; there is very little that you need to do, but some PHP5 changes necessitate some compatability breakages, and the new callback hook architecture and the ability to separate the template engines into plugins introduced some slight changes as well.

In testing the release, I have been writing some apps that take advantage of some of the new features, and I will be writing some tutorials in the coming weeks.

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Always check the version before release

Last week, I had someone bring to my attention that the SPL's Countable interface was actually first released in PHP 5.1.0… which means I needed to update the PHP dependency on Phly_Hash. I also needed to do so on Phly_Config as it depends on Phly_Hash. I released 1.1.1 versions of each yesterday; the only change in each is the PHP version dependency.

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Phly_Struct? no, Phly_Hash...

After some discussion with Paul and Mike, I was convinced that 'Struct' was a bad name for Phly_Struct; structs are rarely if ever iterable, and one key feature of Phly_Struct is its iterable nature.

The question is: what to name it? Associative arrays go by a variety of names in different languages. In Perl, they're 'hashes'; Ruby and Javascript, 'collections'; Python, 'dictionaries'. I ruled out Phly_Dictionary immediately, as (a) I don't want it to be confused with online dictionaries, and (b), it's too long. The term 'Collection' also feels too long (although I write things like Cgiapp2_ErrorException_Observer_Interface, so I don't know why length should be such an issue), as well as unfamiliar to many PHP developers. Hash can imply cryptographic algorithms, but, overall, is short and used often enough in PHP circles that it makes sense to me.

So, I've renamed Phly_Struct to Phly_Hash, and updated Phly_Config to use the new package as its dependency. In addition, I've had it implement Countable, so you can do things like:

$idxCount = count($struct);

Go to the channel page for instructions on adding Phly to your PEAR channels list, and grab the new package with pear install -a phly/Phly_Hash, or pear upgrade -a phly/Phly_Config.

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Introducing Phly_Struct and Phly_Config

I often find myself needing a configuration module of some sort — for storing application parameters, bootstrapping, template variables, what have you. I typically will either:

  1. Create a PHP file that creates and returns an array, and suck that in via include, or
  2. Create an INI file and suck it in via parse_ini_file, or
  3. Create an XML file and suck it in via SimpleXML.

The first method gives great flexibility of structure and types, but isn't portable to other languages (well, not easily; you could turn it into JSON, or serialize it, etc). The second method (INI files) is handy because the syntax is so concise, and can translate to other projects in other languages easily if necessary; however, you can only easily go two levels deep (using [sections] in the file). The third method is very portable, and allows nested structures — but doesn't allow usage of many specific PHP types.

I find, however, that each has their place. The problem, however, is: once I bring them into my project, how can I access them? Better yet, would there be a way to bring in configurations of many types and still access them all in the same way?

Not happy with solutions out there, I did the only logical thing: I reinvented the wheel, and added some new tread of my own.

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mbstring comes to the rescue

I've been working with SimpleXML a fair amount lately, and have run into an issue a number of times with character encodings. Basically, if a string has a mixture of UTF-8 and non-UTF-8 characters, SimpleXML barfs, claiming the "String could not be parsed as XML."

I tried a number of solutions, hoping actually to automate it via mbstring INI settings; these schemes all failed. iconv didn't work properly. The only thing that did work was to convert the encoding to latin1 — but this wreaked havoc with actual UTF-8 characters.

Then, through a series of trial-and-error, all-or-nothing shots, I stumbled on a simple solution. Basically, I needed to take two steps:

  • Detect the current encoding of the string
  • Convert that encoding to UTF-8

which is accomplished with:

$enc = mb_detect_encoding($xml);
$xml = mb_convert_encoding($xml, 'UTF-8', $enc);

The conversion is performed even if the detected encoding is UTF-8; the conversion ensures that all characters in the string are properly encoded when done.

It's a non-intuitive solution, but it works! QED.

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PHP Library Channel

I've been working on Cgiapp in the past few months, in particular to introduce one possibility for a Front Controller class. To test out ideas, I've decided to port areas of my personal site to Cgiapp2 using the Front Controller. Being the programmer I am, I quickly ran into some areas where I needed some reusable code — principally for authentication and input handling.

I've been exposed to a ton of good code via PEAR, Solar, eZ components, and Zend Framework. However, I have several criteria I need met:

  • I want PHP5 code. I'm coding in PHP5, I should be able to use PHP5 libraries, not PHP4 libraries that work in PHP5 but don't take advantage of any of its features.
  • I prefer few dependencies, particularly lock-in with existing frameworks. If I want to swap out a storage container from one library and use one from another, I should be free to do so without having to write wrappers so they'll fit with the framework I've chosen. Flexibility is key.
  • Stable API. I don't want to have to change my code every few weeks or months until the code is stable.
  • I should be able to understand the internals quickly.

So what did I choose? To reinvent the wheel, of course!

To that end, I've opened a new PEAR channel that I'm calling PHLY, the PHp LibrarY, named after my blog. The name implies soaring, freedom, and perhaps a little silliness.

It is designed with the following intentions:

  • Loosely coupled; dependencies should be few, and no base class should be necessary.
  • Extendible; all classes should be easily extendible. This may be via observers, interfaces, adapters, etc. The base class should solve 80% of usage, and allow extensions to the class to fill in the remainder.
  • Designed for PHP5 and up; all classes should make use of PHP5's features.
  • Documented; all classes should minimally have excellent API-level documentation, with use cases in the class docblock.
  • Tested; all classes should have unit tests accompanying them.
  • Open source and commercial friendly; all classes should use a commercial-friendly open source license. The BSD license is one such example.

Please feel free to use this code however you will. Comments, feedback, and submissions are always welcome.

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Cgiapp 1.9.0 released

I released Cgiapp 1.9.0 into the wild last night. The main difference between 1.8.0 and 1.9.0 is that I completely removed the plugin system. I hadn't had any users reporting that they were using it, and, in point of fact, the overloading mechanism I was using was causing some obscure issues, particularly in the behaviour of cgiapp_postrun().

As usual, you can find more information and links to downloads at the Cgiapp site.

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What is Cgiapp?

After some conversations with Paul and Mike, in recent months I realized that while I often announce new releases of Cgiapp, I rarely explain what it is or why I develop it.

~~I got into trouble on the PEAR list when I tried to propose it for inclusion in that project, when I made the mistake of describing it as a framework. (This was before frameworks became all the rage on the PHP scene; PEAR developers, evidently, will not review anything that could possibly be construed or interpreted as a framework, even if it isn't.)~~ I mistakenly called Cgiapp a framework once when considering proposing it to PEAR. But if it's not a framework, what is Cgiapp? Stated simply:

Cgiapp is the Controller of a Model-View-Controller (MVC) pattern. It can be either a front controller or an application controller, though it's typically used as the latter.

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Telcos are Attacking the Internet

I generally try to stay out of politics on this blog, but this time something has to be said, as it affects anyone who uses the internet, at least in the US.

Basically, a number of telcos and cable providers are talking about charging internet content providers — the places you browse to on the internet, places like Google, Yahoo!, Amazon, etc. — fees to ensure bandwidth to their sites. Their argument is that these content providers are getting a 'free ride' on their lines, and generating a lot of traffic themselves, and should thus be paying for the cost of bandwidth.

This is patently ridiculous. Content providers already have to pay for their bandwidth — they, too, have ISPs or agreements with telcos in place, either explicitly or via their hosting providers. Sure, some of them, particularly search engines, send out robots in order to index or find content, but, again, they're paying for the bandwidth those robots generate. Additionally, people using the internet are typically paying for bandwidth as well, through their relationship with their ISP. What this amounts to is the telcos getting paid not just by each person to whom they provide internet access, but every end point on the internet, at least those within the US.

What this is really about is telcos wanting more money, and wanting to push their own content. As an example, let's say your ISP is AOL. AOL is part of Time Warner, and thus has ties to those media sources. Now, those media sources may put pressure on AOL to reduce bandwidth to sites operated by ABC, CBS, NBC, FOX, Disney, PBS, etc. This might mean that your kid can no longer visit the Sesame Street website reliably, because AOL has reduced the amount of bandwidth allowed to that service — but any media site in the TWC would get optimal access, so they could get to Cartoon Network. Not to slam Cartoon Network (I love it), but would you rather have your kid visiting or Basically, content providers would not need to compete based on the value of their content, but on who they can get to subscribe to their service.

Here's another idea: your ISP is MSN. You want to use Google… but MSN has limited the bandwidth to Google because it's a competitor, and won't accept any amount of money to increase that bandwidth. They do the same with Yahoo! So, now you're limited to MSN search, because that's the only one that responds reliably — regardless of whether or not you like their search results. By doing so, they've just artificially inflated the value of their search engine — without needing to compete based on merit.

Additionally, let's say Barnes and Noble has paid MSN to ensure good bandwidth, but part of that agreement is a non-compete clause. Now you find your connections to Amazon timing out, meaning that you can't even see which book provider has the better price on the book you want; you're stuck looking and buying from B&N.

Now, let's look at something a little more close to home for those of us developing web applications. There have been a number of success stories the last few years: MySpace, Digg, and Flickr all come to mind. Would these endeavors have been as successful had they needed to pay multiple times for bandwidth, once to their ISP and once each to each telco charging for content providers? Indeed, some of these are still free services — how would they ever have been able to pay the extra amounts to the telcos in the first place?

So, basically, the only winners here are the telcos.

Considering how ludicrous this scheme is, one must be thinking, isn't the US Government going to step in and regulate against such behaviour? The answer, sadly, is no. The GOP doesn't like regulation, and so they want market forces to decide. Sadly, what this will likely do is force a number of content providers to offshore their internet operations — which is likely to have some pretty negative effects on the economy.

The decision isn't final — efforts can still be made to prevent it (the above link references a Senate committee meeting; there's been no vote on it). Call your representatives today and give them an earful. Tell them it's not just about regulation of the industry, but about fair competition in the market. Allowing the telcos to extort money from content providers will only reduce the US' economic chances in the world, and stifle innovation and choice.

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