Difference between revisions of "PHP"
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[[Category:PHP]] | [[Category:PHP]] | ||
+ | [[category:Webdesign]] | ||
+ | =Basics= | ||
Script language for dynamic web-pages. The syntax and concepts used are similar to [[Perl]] | Script language for dynamic web-pages. The syntax and concepts used are similar to [[Perl]] | ||
− | + | ;Limited number of loops | |
<syntaxhighlight lang=php> | <syntaxhighlight lang=php> | ||
− | + | for ($i = 0; $i <= 6; $i++) { | |
− | + | echo "Loop number: $i "; | |
− | + | } | |
</syntaxhighlight> | </syntaxhighlight> | ||
+ | |||
+ | ;escapeshellcmd(shellcommand) | ||
+ | :Return the shellcommand with everything that might confuse the shell escaped. | ||
+ | ;exec(<cmd>,<outputarray>,<returnvar>) | ||
+ | :Executed <cmd> in the shell, append the command output to he array <outputarray> and set <returnvar> to the returnvalue of the command. | ||
+ | :Also the last line of the command output is returned | ||
+ | ;shell_exec(<cmd>) | ||
+ | :Execute <cmd> (output from excapedshellcmd) in the shell, return the command output. | ||
+ | |||
+ | ;<nowiki>date("Y-m-d h:i:s")</nowiki> | ||
+ | :Current timestamp (YYYY-mm-dd HH:MM:SS). | ||
+ | :Format "U" is [https://duckduckgo.com/?q=unixtime unixtime] (seconds since epoch) | ||
+ | ;sprintf("%7.2f", $float ) | ||
+ | :Format a number (7 digits, 2 decimals) | ||
+ | ;number_format($number, 2, '.', ',') | ||
+ | :Format $number with 2 decimals, . as decimal separator and , as thousand separator. | ||
+ | |||
+ | ;strpos($string, $search,$start) | ||
+ | :Return position of $search exists in $string. When it is not in, return FALSE. Start searching at position $start (optional). Simple test on strpos - <code>if (strpos(x,y)) {}</code> - does not differ between position 0 and FALSE. Test on position 2 or count from the end by setting $start to a negative value (possible since PHP7.1). | ||
+ | ;str_replace($old, $new, $string) | ||
+ | :Return $string with $old replaced by $new | ||
+ | ;trim($string, 'abc') | ||
+ | :Remove characters a, b and c from the start and the end of $string. If no characters are specified all whitespace will be removed. | ||
+ | |||
+ | ;round($float,<precision>) | ||
+ | :Round $float to <precision> decimals (0 is default) | ||
+ | |||
+ | =Regular expressions= | ||
+ | PHP is Perl-like, patterns need delimiters (default is /<pattern>/ ) | ||
+ | ;preg_match($pattern, $string) | ||
+ | :Return 1 if $pattern exists in $string | ||
+ | ;preg_split('/\s*\=+\s*/',$string | ||
+ | :Split $string into an array on a pattern (in this example on white-spaces and equality signs. | ||
+ | ;preg_replace('/#.*$/','',$string); | ||
+ | :Replace matches with the pattern in $string (in this example to remove comments from a line) | ||
+ | |||
+ | =Files= | ||
+ | Almost all you need to know about files. For writing open with 'w' and fwrite($fh,$line) | ||
+ | <syntaxhighlight lang=php> | ||
+ | $fh = fopen($filename, 'r') or die('Unable to open '.$file); | ||
+ | while(!feof($fh)) { | ||
+ | $line = fgets($fh); | ||
+ | } | ||
+ | fclose($fh) | ||
+ | </syntaxhighlight> | ||
+ | |||
=Functions= | =Functions= | ||
− | + | All variables are local to the function. You have to pass everything it needs, or declare variables as GLOBAL | |
<syntaxhighlight lang=php> | <syntaxhighlight lang=php> | ||
− | |||
function func1($arg1, $arg2) | function func1($arg1, $arg2) | ||
{ | { | ||
+ | GLOBAL $vardeclaredoutside | ||
<codeblock> | <codeblock> | ||
return $value; | return $value; | ||
} | } | ||
− | |||
</syntaxhighlight> | </syntaxhighlight> | ||
+ | Only one value can be returned but you can return arrays. | ||
+ | |||
+ | <syntaxhighlight lang=php> | ||
+ | |||
+ | function func1() | ||
+ | { | ||
+ | <codeblock> | ||
+ | return array ($value1, $value2); | ||
+ | } | ||
+ | |||
+ | list($val1,$val2) = func1(); | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | =Arrays= | ||
+ | |||
+ | ;arr = [] | ||
+ | :(Create) empty array | ||
+ | |||
+ | ;arr1 = [val1, val2, val3] | ||
+ | ;arr1 = array(val1, val2, val3) | ||
+ | :Create an indexed array. The keys are the range 0..arraylength. | ||
+ | |||
+ | ;array_push($arr1,val1,val2) | ||
+ | :Add elements val1 and val2 to the end of $arr1 | ||
+ | |||
+ | ;$arr1 = array(key1=>val1, key2=>val2, key3=>val3) | ||
+ | ;$arr2[key1] = val1 | ||
+ | :Create an associative array (like a [[Perl#Hashes]] or a [[Python:DataTypes#Dictionary_or_dict|Python dictionay]]) | ||
+ | |||
+ | ;count($arr1) | ||
+ | :Return the number of elements (length) of an array | ||
+ | |||
+ | ;end($arr1) | ||
+ | :Return the value of the last element in $arr1 and set the pointer to it. | ||
+ | |||
+ | ;join(',',$arr1) | ||
+ | :Join elements in arr1 with ',' as separator. | ||
+ | |||
+ | ;foreach($arr1 as $value) { codeblock } | ||
+ | :Loop over an indexed array | ||
+ | |||
+ | ;foreach($arr1 as $key => $value) { codeblock } | ||
+ | :Loop over an associative array | ||
+ | |||
+ | ;unset($arr1[key]) | ||
+ | :Remove the key element from $array. Numerical keys will not be reindexed. | ||
=Install= | =Install= | ||
Line 30: | Line 123: | ||
:Fix php security by editing <code>/etc/php/7.0/fpm/php.ini</code> | :Fix php security by editing <code>/etc/php/7.0/fpm/php.ini</code> | ||
:Uncomment line with cgi.fix_pathinfo and set it to 0 | :Uncomment line with cgi.fix_pathinfo and set it to 0 | ||
+ | |||
+ | ==php7.4 not in repository== | ||
+ | <syntaxhighlight lang=bash> | ||
+ | apt -y install lsb-release apt-transport-https ca-certificates | ||
+ | wget -O /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg | ||
+ | echo "deb https://packages.sury.org/php/ $(lsb_release -sc) main" | sudo tee /etc/apt/sources.list.d/php.list | ||
+ | sudo apt update | ||
+ | sudo apt -y install php7.4 | ||
+ | php -v | ||
+ | </syntaxhighlight> |
Latest revision as of 22:52, 7 October 2023
Basics
Script language for dynamic web-pages. The syntax and concepts used are similar to Perl
- Limited number of loops
for ($i = 0; $i <= 6; $i++) {
echo "Loop number: $i ";
}
- escapeshellcmd(shellcommand)
- Return the shellcommand with everything that might confuse the shell escaped.
- exec(<cmd>,<outputarray>,<returnvar>)
- Executed <cmd> in the shell, append the command output to he array <outputarray> and set <returnvar> to the returnvalue of the command.
- Also the last line of the command output is returned
- shell_exec(<cmd>)
- Execute <cmd> (output from excapedshellcmd) in the shell, return the command output.
- date("Y-m-d h:i:s")
- Current timestamp (YYYY-mm-dd HH:MM:SS).
- Format "U" is unixtime (seconds since epoch)
- sprintf("%7.2f", $float )
- Format a number (7 digits, 2 decimals)
- number_format($number, 2, '.', ',')
- Format $number with 2 decimals, . as decimal separator and , as thousand separator.
- strpos($string, $search,$start)
- Return position of $search exists in $string. When it is not in, return FALSE. Start searching at position $start (optional). Simple test on strpos -
if (strpos(x,y)) {}
- does not differ between position 0 and FALSE. Test on position 2 or count from the end by setting $start to a negative value (possible since PHP7.1). - str_replace($old, $new, $string)
- Return $string with $old replaced by $new
- trim($string, 'abc')
- Remove characters a, b and c from the start and the end of $string. If no characters are specified all whitespace will be removed.
- round($float,<precision>)
- Round $float to <precision> decimals (0 is default)
Regular expressions
PHP is Perl-like, patterns need delimiters (default is /<pattern>/ )
- preg_match($pattern, $string)
- Return 1 if $pattern exists in $string
- preg_split('/\s*\=+\s*/',$string
- Split $string into an array on a pattern (in this example on white-spaces and equality signs.
- preg_replace('/#.*$/',,$string);
- Replace matches with the pattern in $string (in this example to remove comments from a line)
Files
Almost all you need to know about files. For writing open with 'w' and fwrite($fh,$line)
$fh = fopen($filename, 'r') or die('Unable to open '.$file);
while(!feof($fh)) {
$line = fgets($fh);
}
fclose($fh)
Functions
All variables are local to the function. You have to pass everything it needs, or declare variables as GLOBAL
function func1($arg1, $arg2)
{
GLOBAL $vardeclaredoutside
<codeblock>
return $value;
}
Only one value can be returned but you can return arrays.
function func1()
{
<codeblock>
return array ($value1, $value2);
}
list($val1,$val2) = func1();
Arrays
- arr = []
- (Create) empty array
- arr1 = [val1, val2, val3]
- arr1 = array(val1, val2, val3)
- Create an indexed array. The keys are the range 0..arraylength.
- array_push($arr1,val1,val2)
- Add elements val1 and val2 to the end of $arr1
- $arr1 = array(key1=>val1, key2=>val2, key3=>val3)
- $arr2[key1] = val1
- Create an associative array (like a Perl#Hashes or a Python dictionay)
- count($arr1)
- Return the number of elements (length) of an array
- end($arr1)
- Return the value of the last element in $arr1 and set the pointer to it.
- join(',',$arr1)
- Join elements in arr1 with ',' as separator.
- foreach($arr1 as $value) { codeblock }
- Loop over an indexed array
- foreach($arr1 as $key => $value) { codeblock }
- Loop over an associative array
- unset($arr1[key])
- Remove the key element from $array. Numerical keys will not be reindexed.
Install
On debian (and its derivates)
- apt-get install php-fpm php-mysql
- Install php7 and mysql support
- Fix php security by editing
/etc/php/7.0/fpm/php.ini
- Uncomment line with cgi.fix_pathinfo and set it to 0
php7.4 not in repository
apt -y install lsb-release apt-transport-https ca-certificates
wget -O /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg
echo "deb https://packages.sury.org/php/ $(lsb_release -sc) main" | sudo tee /etc/apt/sources.list.d/php.list
sudo apt update
sudo apt -y install php7.4
php -v