In a new post to the Developer Tutorials blog Akash Mehta takes a look at migrating PHP4 applications up to the more recent versions of PHP5.

PHP 5 supports most of the legacy syntax features of PHP 4. Most code written for PHP 4 should function fine under PHP 5, and a comprehensive test suite could check this. However, many of the backwards-incompatible changes in PHP 5 were in regard to language quirks, and quite a few hacks rely on these in order to function.

He points out some of these hacks including changes to the object model and updates to the way variables are handled (breaking many "bad use" cases). He also points out the changes made in the latest Windows binaries as well as some of the new reserved keywords that could conflict with pre-existing code in your application.

Eirik Hoem has posted an update on a previous problem he was having when working with SOAP in PHP and its handling of arrays.

The scenario was that when an array with only one object was returned over SOAP the array was discarded and pointed straight to the single object.

Come to find out, this behavior wasn't a bug, it was a feature - the fix is to add another parameter to the initialization of the SoapClient to add the SOAP_SINGLE_ELEMENT_ARRAYS feature.

John Lim has posted about an interesting bug he's come across when working with the output of two strings that should look the same:

Someone reported a bug in ADOdb, the open source db library i maintain. I went crazy for half an hour until i realised the problem.

According to him, "if you expect the above code to produce the same values, you are sadly mistaken". His example gives an interesting result for the first echo statement - not echoing the 9 in the first character like it seems would make sense. Check out his post for the code and try it out for yourself.

David Coallier has posted his look at the namespace support that will be included with PHP6, specifically some examples of their basic usage and things to look out for when using them in your applications.

Well, PHP has namespaces now! Time to start educating people on that long awaited feature and for the people that already do know namespaces from C++, you also need to read this, it's simple, but will give you the basic syntax.

He starts with things like "what is a namespace?" or "what are they used for?" before getting into the syntax. The next step up is explaining how they work - he uses an example project, ProjectOne, with its namespace definition and an example script (invoke.php) that uses this class (including the new "import" keyword and the double-colon namespace separator).

If you work with streams in PHP, Dotvoid has a tip that just might come in handy some day in the future. The tip deals with the difference between HTTP 1.1 and 1.0.

I have a class that I wrote some time ago that is called URLImporter. It's simple, does what it is supposed to do and thus makes my life easier. Essentially it helps me fetch URL resources - mostly dynamically generated data from password protected extranets that require me to use HTTP POST.

Up until recently this class have only been used behind an http proxy. The other day I moved it to another machine - that is not behind a proxy and suddenly it stopped working.

He realized the problem after a bit of research - HTTP 1.1 automatically performs a "keep alive" on the connection, not timing out after the transaction's done like 1.0 does. His solution? Passing another HTTP header to the stream connection: "Connection: close".