php tips and tricks

PHP tips and tricksSkien, Norge, June 7th 2007

Agenda

Tips and Tricks from PHPNo need for anything else than standard distributionAll for PHP 5( but lots of it is also valid in PHP 4 )

The month of PHP functions

Who is speaking?

Damien SéguyNexen Services, eZ publish silver partner for hostingPHP / MySQL servicesRedacteur en chef of www.nexen.netPhather of an plush Elephpant

http://www.nexen.net/english.php

Nod when you know about it

Random stuff

rand() and mt_rand()

array_rand() : extract info from an array

extract keys!

shuffle() : shuffle an array before deal

str_shuffle() : shuffle a string

Random stuff

<?php$a = range('a','d');shuffle($a);

print_r($a);

print_r(array_rand($a,3));

print str_shuffle('abcdef');// eabdcf?>

Array( [0] => c [1] => d [2] => b [3] => a)Array( [0] => 0 [1] => 1 [2] => 3)

Arrays combinaisons

array_combine() : turn two arrays into one

Inverse to array_keys() and array_values()<?php$a = array('green', 'red', 'yellow');$b = array('avocado', 'apple', 'banana');$c = array_combine($a, $b);

print_r($c);?>

Array( [green] => avocado [red] => apple [yellow] => banana)

Arrays combinaisons

array_combine() : turn two arrays into one

PDO::FETCH_KEY_PAIR : combine 2 columns in a hash

<?php $html = file_get_contents("http://www.php.net/");

//'<a href="http://php.net">PHP</a>'; if (preg_match_all('#<a href="(http://[^\"/\?]+/).*?>(.*?)</a>#s', $html, $r)) {     $liste = array_combine($r[2], $r[1]); } print_r($liste);

?>

Arrays as SQL

array_count_values() : makes easy stats

Works like a GROUP BY and COUNT()

<?php $array = array(1, "hei", 1, "takk", "hei"); print_r(array_count_values($array));?> Array

( [1] => 2 [hei] => 2 [takk] => 1)

sort ∅ r u∅ ∅ r uk k kr uka a ar ua

Arrays as SQL

array_multisort() : sort several arrays at once

Works like a ORDER BY

Array( [0] => 2 [1] => 3 [2] => 4 [3] => 5)Array( [0] => d [1] => c [2] => b [3] => a)

<?php$ar1 = array(5,4,3,2);$ar2 = array('a','b','c','d');array_multisort($ar1, $ar2);array_multisort($ar1, SORT_ASC,SORT_STRING, $ar2);?>

Fast dir scans

scandir(‘/tmp’, true);

Include name sorting

Replace opendir, readdir, closedir and a loop!

glob(‘*.html’);

Simply move the loop out of sight

Fast dir scans

Array( [0] => sess_um8rgjj10f6qvuck91rf36srj7 [1] => sess_u58rgul68305uqfe48ic467276 [2] => mysql.sock [3] => .. [4] => .)Array( [0] => /tmp/sess_um8rgjj10f6qvuck91rf36srj7 [1] => /tmp/sess_u58rgul68305uqfe48ic467276)

<?phpprint_r(scandir('/tmp/', 1));print_r(glob('/tmp/sess_*'));?>

URL operations

parse_url()

break down into details

do not make any check

parse_str()

split a query string

separate and decode, as long as it can

Fill up an array or globals

URL

<?php$url = 'http://login:pass@www.site.com/ path/file.php?a=2+&b%5B%5D= %E5%AF%B9%E4%BA%86%EF%BC%81#ee';$d = parse_url($url);print_r($d);

parse_str($d["query"]);var_dump($GLOBALS["b"]); ?>

URL

( [scheme] => http [host] => www.site.com [user] => login [pass] => pass [path] => /path/file.php [query] => a=2&b%5B%5D=%E5%AF%B9%E4%BA%86%EF%BC%81 [fragment] => ee)array(1) { [0]=> string(9) "对了！"}

URL validations

scheme : list your own

host : checkdnsrr() to check

path : realpath() + doc root (beware of mod_rewrite)

query : parse_str()

beware of the second argument!

don’t handle &amp;

URL rebuilding

<?phpprint http_build_query( array_merge($_GET , array(' de ' => '对了！')));?>

+de+=%E5%AF%B9%E4%BA%86%EF%BC%81

http_build_query()

rebuild your query

takes into account encoding and arrays

URL testing

<?php get_headers('http://localhost/logo.png');?>

Array( [0] => HTTP/1.1 200 OK [1] => Date: Mon, 12 Feb 2007 02:24:23 GMT [2] => Server: Apache/1.3.33 (Darwin) PHP/5.2.1 [3] => X-Powered-By: eZ publish [4] => Last-Modified: Fri, 30 Sep 2005 09:11:28 GMT [5] => ETag: "f6f2a-dbb-433d0140" [6] => Accept-Ranges: bytes [7] => Content-Length: 3515 [8] => Connection: close [9] => Content-Type: image/png)

PHP is dynamic

Variables variables<?php $x = 'y'; $y = 'z'; $z = 'a';

echo $x;  // displays y echo $$x;  // displays z echo $$$x; // displays a ?>

Variable constants

Still one definition

Dynamic constant value

<?php   define ("CONSTANT", 'eZ Conference');   echo CONSTANT;   echo constant("CONSTANT");  ?>

See the runkit to change constants...

Juggling with variables

Compact() and extract()<?php   $x = 'a'; $y = 'b';   $z = compact('x','y');   // $z = array('x'=> 'a', 'y' => 'b'); 

$r = call_user_func_array('func', $z);  // calling func($x, $y); 

extract($r);  // $x = 'c'; $y = 'd'; $t = 'e'; list($x, $y, $t) = array_values($r); ?>

Variable functions

<?php  $func = 'foo'; $foo = 'bar'; $class = 'bb';

 $func($foo); // calling foo with bar call_user_func($func, $foo);// same as above

 call_user_func(array($class, $func), $foo);  // now with objects! $class->$func($foo); // same as above ?>

Variable functions

<?php $func = 'f'; // a function // beware of langage construct such as empty()

$func = array('c','m'); // a static call to class c

$func = array($o,'m'); // a call to object o

call_user_func($func, $foo);?>

Object magic

__autoload() : load classes JIT

__sleep() and __wakeup()

Store object and ressources in sessions

__toString() : to turn an object to a string

__toArray() : get_object_vars($object);

__toInteger() : may be?

Output buffering

<?phpob_start("ob_gzhandler");echo "Hello\n";setcookie("c", "v");ob_end_flush();?>

Avoid ‘already sent’ bug

Clean it : tidy

Compress it : gz

Cache it

Caching

if ( filemtime($cache)+3600 < time()) {     include($cachefile);     exit; } ob_start();

  $content = ob_get_contents();    file_put_contents('cache', $contents);   ob_end_flush();

auto_prepend :

auto_append :

Auto-caching upon 404 error pages

Connexion handling

PHP maintains the connexion status

0 Normal; 1 Aborted; 2 Timeout

ignore_user_abort() to make a script without interruption

connexion_status() to check status

Register for shutdown

Function executed at script shutdown

Correct closing of resources

More convenient than ignore_user_abort() a library

In OOP, better use __destruct()

Storing calculated variables

Variables export

var_export() : recreate PHP code for a variable

<?php

$array = array(5,4,3,2);

file_put_contents('file.inc.php', '<?php $x = '. var_export($array, true). '; ?>');?>

array ( 0 => 5, 1 => 4, 2 => 3, 3 => 2,)

Assertions

Include tests during execution

Assertion are an option (default is on) :

Most clever way than removing than echo/var_dump

Common practice in other languages

Programmation by contract

Assertions

<?php assert_options(ASSERT_CALLBACK,'assert_callback'); function assert_callback($script,$line, $message){    echo 'There is something strange  in your script <b>', $script,'</b> :  line <b>', $line,'</b> :<br />'; exit; }

assert('is_integer( $x );' );   assert('($x >= 0) && ($x <= 10);  //* $x must be from 0 to 10' );   echo "0 <= $x <= 10"; ?>

Debugging

get_memory_usage()

memory_limit is now on by default

Better memory handling

The fake growth of memory needs

get_peak_memory_usage()

Debugging

get_included_files()

get_defined_constants/functions/vars()

get_declared_classes()

get_debug_backtrace()

function stack and their arguments

file and line calling

Debugging

array(2) {[0]=>array(4) { ["file"] => string(10) "/tmp/a.php" ["line"] => int(10) ["function"] => string(6) "a_test" ["args"]=> array(1) { [0] => &string(6) "friend" }}[1]=>array(4) { ["file"] => string(10) "/tmp/b.php" ["line"] => int(2) ["args"] => array(1) { [0] => string(10) "/tmp/a.php" } ["function"] => string(12) "include_once" }}

Slides

http://www.nexen.net/english.php

damien.seguy@nexen.net

http://www.nexenservices.com/

Everyone loves PHP