Zend Framework View Script Recursion

We know that in Zend Framework View Scripts it’s possible  to run in a recursion using a View Helper – either Partial, or Action, or a custom one.

However all of these become a certain execution overhead in case we need just a simple one-time tree traversal. Also for readability purpose, it would be nice to have the recursion defined inline.

Luckily, since PHP 5.3 we can use self referencing closures to define the behavior within the script:

<?php
$showTree = function(array $entities) use(&$showTree) {?>
 <?if(!$entities) return?>
 <ul>
 <?foreach($entities as $entity):?>
 <li><?=$entity->getName()?></li>
 <?=$showTree($entity->getChildren())?>
 <?endforeach?>
 </ul>
<?}
?>
<?=$showTree($this->entities)?>

Making Collective Decisions

While preparing to shrink up and replace my single role of Lead Software Architect with a Software Architecture team -

Decision Making

Making architectural decisions might seem easy and fun, but can have multiple consequences which can affect state and integrity of the software, the architecture team, the R&D teams and the whole company. We aim to make the decisions in the most responsible manner with taking all the relevant factors in consideration. Sometimes we do consult wide community of developers and PMs in early stages, sometimes we do that on later stages, but what’s very important, we never attempt to dictate our decision without majority consensus. The common flow of taking a decision is the following (CRAFT): Collect information about the subject from provided private and public sources. If necessary, use in-company resources reuse their existing experience. Research the gathered information and prepare a draft of architectural opinion with a list of alternative solutions and their advantages and disadvantages. Acknowledge the opinion of all the interested parties. Accept and react on all the provided input. Finalize the decision and make it effective. Make sure it’s acknowledged, accepted and adopted by all the relevant parties. Track the execution of the decision. Learn from the experience, reopen the flow if necessary.

Simple No-Framework Object Oriented Multi-Layer MVC Application Example

Recently I’ve created the subj. It’s a memory game, written in pure PHP/HTML, called “PHP Memory”.

What was important for me to demonstrate is the next principles:

1. Even if you don’t use a framework, you should write modular code with appropriate architecture.
2. Despite that, the application design and code should match its required functionality with no overhead of unneeded patterns and abstraction or preparations for future enhancements, unless they’re planned.
3. Nevertheless, the code should be readable and maintainable.
4. The bottom line is – developing a framework versus developing an application are completely different tasks. The strategy and tactics should vary very much. Of course, developers should learn from the frameworks source code, since they accumulate collective experience of great coders, but the ideas implemented in frameworks sometimes not required or even harmful while developing an application.

The demo and source code can be found here.

cURL HTTP1.1 empty POST bug

Today we spent almost 2 hours on a weird discrepancy between our development and staging environments. It’s pretty rare, that I experience such low level issue, thus in my opinion it’s worth mentioning here.

Last weeks we were busy developing integration to a new data vendor. Everything went well until we deployed the application to stage.
Suddenly we started receiving HTTP status 411 on one of the calls. Since we work with cURL library, which we believed is stable enough, we thought the problem is somewhere between the source code and environment configuration.

Later we found that the same request gets accepted if sent from a client other than cURL (e.g. chrome-poster). The unique about this request is that it’s sent with POST method (the vendor’s strict requirement) but the content body is empty.

In the end we discovered that newer version (since 7.20) of cURL interprets missing body as a negotiation request – sends Expect: 100-continue header and Content-Length: -1.

So, the immediate solution was to send empty content body (zero-length string) to cURL, which aligned the behavior in all the environments.

On the way we discovered a useful option CURLINFO_HEADER_OUT, which enables a possibility to further retrieve the headers sent by cURL to the remote host. From now we use it in our error handling mechanism to trace the sent headers as well.

What can we conclude from this story?

1. Try to synchronize the software of all of your environments. If possible, use exactly the same version OS version, libraries, tools, etc. It’s very easy if you host your applications on VPS and use VMs for development and staging servers. The least convenient case is when you have OSs of different architecture and (e.g. Windows for development and Linux for production).
2. Don’t underestimate importance of error handling. Find the optimal level of handling for your application, which will be easily extended and configured.

Hope my sincere advices will help you, my dear friend, to save your precious time.

Occasion

Today I’ve been told the second time in my life that I look Abdullah Hussein. Sceptical but intrigued, I performed an experiment to prove the opposite. The result clearly demonstrates absurdity and futility of this bold assumption. Observe.

PHP: array_merge versus array union operator (+)

It comes that even experienced PHP developers don’t remember what is the difference between running array_merge((array)$a1, (array)$a2) and (array)$a1+(array)$a2. The answer is given @ php.net, no need to guess and argue.

Here is the difference:

Array Union: The + operator appends elements of remaining keys from the right handed array to the left handed, whereas duplicated keys are NOT overwritten.

array_merge(): If the input arrays have the same string keys, then the later value for that key will overwrite the previous one. If, however, the arrays contain numeric keys, the later value will not overwrite the original value, but will be appended. If all of the arrays contain only numeric keys, the resulting array is given incrementing keys starting from zero.

Phing plugin for Eclipse PDT

I love Ant integration into Eclipse JDT – it provides smart editor, handy auto-completion, and the most important – fully functional debugger.

Recently I have been laboring on porting a deployment system from shell scripts to Phing, a loose PHP port of Ant. And naturally, I miss the above. I still get a little aid from Eclipse – since Phing’s syntax is very close to Ant’s, I can at use Ant editor for Phing files to enjoy property navigation and target integrity validation.

I would be more than happy to announce that I’m going to fill the gap and implement Phing plugin for Eclipse PDT, but unfortunately – I’m too busy and too lazy. On the other hand, if you, my dear friend, will suddenly decide to accept this challenge, I can gladly invest my time in architecture, design, review & testing free of charge. Or should I anyway try to start it myself?