PHP/MySQL tips and tricksWashington DC, USA, November 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 )

No petting the elePHPant until the end of the session

Who is speaking?

Damien SéguyNexen Services, Open Source hosting companyPHP / MySQL expert servicesRedacteur en chef of www.nexen.netPHather of thousands plush Elephpants

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

Nod when you know about it

PHP 5 : PHP 4 on diet?

PHP 5 : 67 extensions bundledPHP 5 : 2144 functionsPHP 5 : 158 classes....(watch for DateTime)

PHP 4 : 77 extensions bundledPHP 4 : 2459 functionsPHP 4 : 3 classes

Random stuff

<?php$a = range('d','a');shuffle($a);

print_r($a);

print str_shuffle('abcdef');// eabdcf

print_r(array_rand($a,3));?>

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

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

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)

array_combine() applied

<?php $a = range('e','a');

$shuffled_a = array_combine( array_rand($a,5),  array_values($a)); // eabdcf

shuffle($a); ?>

Arrays as SQL

sort ∅ r u

∅ ∅ r u

k k kr uk

a a ar ua

Slicing array in chunks : PHP

<?php   $array = range(1,5);   print_r(array_chunk($array,2)); ?>

Array( [0] => Array ( [0] => 1 [1] => 2 )

[1] => Array ( [0] => 3 [1] => 4 )

[2] => Array ( [0] => 5 )

)

Slicing array in chunks : SQL

mysql> SET @a := 1; mysql> SELECT @a, GROUP_CONCAT(i) FROM integers GROUP BY ROUND((@a := @a + 1) / 4 , 0); +------+-----------------+| @a | group_concat(i) |+------+-----------------+| 2 | 0,1,2,13 | | 6 | 4,15,6,7 | | 12 | 11,8,9 | +------+-----------------+3 rows in set (0.00 sec)

+------+| i |+------+| 0 | | 1 | | 2 | | 13 | | 4 | | 15 | | 6 | | 7 | | 8 | | 9 | | 11 | +------+

JOIN is faster than LIMIT

mysql> SELECT cols FROM TABLE LIMIT 1000, 10;

JOIN is faster than LIMIT

mysql> CREATE TABLE `table_limit` ( `row` int(10) unsigned NOT NULL AUTO_INCREMENT, `id` int(11) unsigned DEFAULT NULL, UNIQUE KEY `id` (`id`) );

mysql> INSERT INTO table_limit SELECT 0, id FROM table ORDER BY col;

mysql> SELECT col FROM table_limit JOIN table ON bl_content.id = bl_content_nav.id AND table_limit.row BETWEEN @offset AND @offset + 10

JOIN is faster than LIMIT

Arrays sorted as SQL cols

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);?>

GROUP BY PHP!

DISTINCT : array_unique()

COUNT(*) and GROUP BY : array_count_values()

Hint : array_count_values() is always faster that array_unique()...

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

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

Hide those loops to me!

<?php  while(list($key, $val) = each($array)) {  print "$key => $val\n"; }

for($i = 0; $i<count($array); $i++) {  print "$i => {$array[$i]}\n"; } ?>

Hide those loops to me!

<?php $array = range(1,3); foreach($array as $id => &$value) {    $value++; } ?>

Array( [0] => 2 [1] => 3 [2] => 4)

Declare your objects as Iterators

Hidden loops

array_map : apply a function to all elements

array_walk_recursive : same as above, and multi-dimensional

array_filter : extract all elements using a custom function

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

<?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 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

Fills up an array or $GLOBALS

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() : PHP 5 only

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 ?>

PHP is crazy

Crazy variables

<?php $美国 = 'works'; $êtrânçé = 'works'; ${'Utter madness?'} = 'works'; ${''} = 'works'; ?>

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,)

Fast file exports

file_put_contents($file_name, $content);

accept contexts and streams

Complementary to file_get_contents()

fputcsv() : create CSV style files

complementary to fgetcsv()

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

get_peak_memory_usage()

sys_getloadavg() : no more need for exec(’uptime’);

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