PHP tips and tricks

PHP tips and tricks
Skien, Norge, June 7th 2007

Agenda

Tips and Tricks from PHP
No need for anything else than standard distribution
All for PHP 5
( but lots of it is also valid in PHP 4 )

The month of PHP functions

Who is speaking?

Damien Séguy
Nexen Services, eZ publish silver partner for hosting
PHP / MySQL services
Redacteur en chef of www.nexen.net
Phather of an plush Elephpant
http://www.nexen.net/english.php

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

Array
<?php (
$a = range('a','d'); [0] => c
shuffle($a); [1] => d
[2] => b
print_r($a); [3] => a
)
print_r(array_rand($a,3)); Array
(
print str_shuffle('abcdef'); [0] => 0
// eabdcf [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, $b);
Array
print_r($c);
(
?>
[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(quot;http://www.php.net/quot;);

//'<a href=quot;http://php.netquot;>PHP</a>';
if (preg_match_all(
'#<a href=quot;(http://[^quot;/?]+/).*?>(.*?)</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
$array = array(1, quot;heiquot;, 1, quot;takkquot;, quot;heiquot;);
print_r(array_count_values($array));
?>
Array
(
sort r u
[1] => 2
r u
[hei] => 2
k k kr uk
[takk] => 1
a a ar ua )

Arrays as SQL

Array
(
array_multisort() : sort several [0] => 2
arrays at once [1] => 3
[2] => 4
Works like a ORDER BY
[3] => 5
<?php )
$ar1 = array(5,4,3,2); Array
$ar2 = array('a','b','c','d'); (
array_multisort($ar1, $ar2); [0] => d
array_multisort($ar1, [1] => c
SORT_ASC,SORT_STRING, [2] => b
$ar2); [3] => a
?> )

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
<?php
[3] => ..
print_r(scandir('/tmp/', 1));
[4] => .
print_r(glob('/tmp/sess_*'));
)
?>
Array
(
[0] => /tmp/sess_um8rgjj10f6qvuck91rf36srj7
[1] => /tmp/sess_u58rgul68305uqfe48ic467276
)

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($d[quot;queryquot;]);
var_dump($GLOBALS[quot;bquot;]);
?>

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) quot; quot;
}

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 &

URL rebuilding

http_build_query()
rebuild your query

takes into account encoding and arrays

<?php
print http_build_query(
array_merge($_GET ,
array(' de ' => ' ')));
?>

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

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: quot;f6f2a-dbb-433d0140quot;
[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 (quot;CONSTANTquot;, 'eZ Conference');
 echo CONSTANT;
 echo constant(quot;CONSTANTquot;);
?>

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

Avoid ‘already sent’ bug
Clean it : tidy
<?php
Compress it : gz
ob_start(quot;ob_gzhandlerquot;);
Cache it echo quot;Hellonquot;;
setcookie(quot;cquot;, quot;vquot;);
ob_end_flush();
?>

Caching

auto_prepend :
if ( filemtime($cache)+3600 < time()) {
 include($cachefile); exit;
}
ob_start();
auto_append :
 $content = ob_get_contents();
 file_put_contents('cache', $contents);
 ob_end_flush();

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 (
0 => 5,
$array = array(5,4,3,2);
1 => 4,
2 => 3,
file_put_contents('file.inc.php',
3 => 2,
'<?php $x = '.
)
var_export($array, true).
'; ?>'
);
?>

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 ', $script,' :
line ', $line,' : '; exit;
}

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

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) {
[quot;filequot;] => string(10) quot;/tmp/a.phpquot;
[quot;linequot;] => int(10)
[quot;functionquot;] => string(6) quot;a_testquot;
[quot;argsquot;]=>
array(1) { [0] => &string(6) quot;friendquot; }
}
[1]=>
array(4) {
[quot;filequot;] => string(10) quot;/tmp/b.phpquot;
[quot;linequot;] => int(2)
[quot;argsquot;] =>
array(1) { [0] => string(10) quot;/tmp/a.phpquot; }
[quot;functionquot;] => string(12) quot;include_oncequot;
}
}

Slides

http://www.nexen.net/english.php
damien.seguy@nexen.net
http://www.nexenservices.com/

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