Monthly Archives: June 2010
Vuvuzela in PHP
My website is slow. What can I do?
Don’t assume anything
Measure the problem
Cache it
Do it offline
Database Connections.
Debug flags
Detecting errors and bottle necks in PHP.
In this post I want to make a short list of different ways to detect errors and bottle necks in our PHP projects. It’s an informal list of recommendations and best practises useful at least for me
Indent code.
Python has a great characteristic. Code blocks are defined with indentation. Not with any especial character like other program languages. That’s means if you don’t want syntax errors and you want to execute your program, your script must be properly indented. That’s is a great practise., even in program languages not as restrictive as python with code indention. For example when I need to check a piece of code with a any kind of error, if it isn’t correctly indented I start to indent it. I know it isn’t necessary but for me at least it helps me to understand the code (if I’m not the original developer of the code) and quickly find errors like wrong if clauses and another things like that.
Analyze code and check syntax
You must use a modern text editor or IDE with at least check syntax and also code analyze tools. That’s mandatory. Chose what you want but use one. Zend Studio is a great tool but you also can do it with another editors, even with vi. You can programing PHP with notepad but it’s definitely a waste of time. You will use significant less time programming with modern IDE. I like Zend Studio code Analyzer. It helps you with errors easy to implement and difficult to find like :
// error 1
if ($a=1) {
// error 2
$variable= 2;
if ($Variable == 2) {
...
}
I like to fix every warning even if those warnings are recommendations and not in fact a problem.
Check indentation level.
Even with a perfect indentation big indentation level is a clear signal of “code smell”. Take care of it. If you see a big indentation level you must ask yourself: Is it really the way to do it?
Loops.
If you want to check performance issues and you don’t have too many time,focus yourself finding loops and analyze them. If there is a performance problem is very probably to discover your problem inside a loop. One slow operation executed one time is a problem. But if this operation is executed 1000 times inside a loop is definitely a big problem. OK it’s the same problem but the impact is 1000 times bigger.
Copy-paste code
Avoid them like a plague. It can be helpfully and attractive but the use of the same piece of code distributed among a set of source code files will give you definitely a headache in the future, Be sure about it. We have a lot techniques in to avoid copy and paste code.
PHPDoc, code completion and iterations with PHP
Let’s start with an example
class MyClass
{
function hello($name)
{
return "Hello " . $name . "\n";
}
}
When we want to use this class and we type:
$obj = new MyClass; echo $obj-> <------ code completion appear in our IDE suggesting hello function
But now we put a simple singleton function in MyClass
class MyClass
{
private static $_instance = null;
function singleton()
{
if (is_null(self::$_instance)) {
self::$_instance = new self;
}
return self::$_instance;
}
function hello($name)
{
return "Hello " . $name . "\n";
}
}
And we use our singleton:
echo MyClass::singleton()-> <---- ups nothing happens
That’s because our IDE doesn’t know the return type of our singleton function. Because of that we are going to help to our IDE with a bit of PHPDoc magic.
private static $_instance = null;
/**
* @return MyClass
*/
function singleton()
{
if (is_null(self::$_instance)) {
self::$_instance = new self;
}
return self::$_instance;
}
And now our IDE will help us.
And now something a bit different. We have other class:
class MyClass2
{
static function getAll()
{
return array(new MyClass, new MyClass, new MyClass);
}
}
According to PHPDoc manual we can hint getAll function with @return array[int]MyClass but code completion doesn’t work, at least on my tests (please tell me I’m wrong because it’s the best solution).
So I need to use a small trick to get the autocompletion:
foreach (MyClass2::getAll() as $row) {
/* @var $row MyClass */
echo $row-> <------------------- code completion appear
}
I’ve tried with @return array[int]MyClass and also using SPL Iterators but that’s the only way I know to ensure autocompletion.
Other possible solution is use a dummy cast function in MyClass. It’s a bit ugly solution but also works always:
/**
* @param MyClass $cls
* @return MyClass
*/
static function cast($cls)
{
return $cls;
}
Now We can use:
foreach (MyClass2::getAll() as $row) {
echo MyClass::cast($row)->hello("Gonzalo"); // code completion works
}
