See Apache Webserver Tips

var was the keyword for defining a member variable within a class. Since php5 it should never appear anywhere.

For hashtables use this syntax:

echo "A banana is {$fruits['banana']}.";

• __FILE__: The full path and filename of the file, see language.constants.predefined
• $_SERVER['PHP_SELF']: filename of the currently executing script, relative to the document root, see reserved.variables
• HTTP POST variables: $_POST

Arrays - Array Functions

$fruits = array (
  "fruits"  => array ("a"=>"orange", "b"=>"banana", "c"=>"apple"),
  "numbers" => array (1, 2, 3, 4, 5, 6),
  "holes"   => array ("first", 5 => "second", "third")
);

foreach ($fruits as $fruit) {...}         // traverse the array
foreach ($fruits as $key => $fruit) {...} // same if indices are needed
$length= count($fruits); // get number of items
print_r($fruits);        // print content

Access to a nonexisting key generates a PHP notice. To prevent this, you can check before the access if the key exists or if the value is set. More

array_key_exists('key', $fruits)) // returns true if the key exists
isset($fruits['key']) // returns true if the key exists AND value != NULL

By default, arrays are copied by value (Unlike PHP objects and Java arrays and objects):

$a=array(0);
 
$b= $a;  /* Deep copy: Assignment by value */
$b[0]= 1;
assert($a[0] == 0);
 
$c= &$a; /* Shallow copy: Assignment by reference */
$c[0]= 2;
assert($a[0] == 2);
$a[0]= 3;
assert($c[0] == 3);
 
$d= $c;  /* $c is not different from $a: Again assignment by value */
$d[0]= 4;
assert($a[0] == 3);
assert($c[0] == 3);

function f($v)  { $v[0]= 1; }
function g(&$w) { $w[0]= 2; }
function h(&$x) { $x[0]= 3; return $x; }
$a= array(0);
 
f($a);     /* pass-by-value */
assert($a[0] == 0);
 
f(&$a); /* Call-time pass-by-reference works, but is deprecated! */
assert($a[0] == 1);
 
g($a);     /* pass-by-reference */
assert($a[0] == 2);
 
$b= h($a);          /* return-by-reference seems to be default */
assert($a[0] == 3); /* (pass-by-reference just to make it verifiable) */

$a= array(0);
$b= array('d'=> $a, 'e'=> &$a);
 
$a[0]= 1;
assert($b['d'][0] == 0);
assert($b['e'][0] == 1);

class C {
    public function f(&$v) { $this->v=  $v; $this->v[0]= 1; }
    public function g(&$w) { $this->w= &$w; $this->w[0]= 2; }
}
$o= new C();
$a= array(0);
 
$o->f($a);
assert($a[0] == 0);
 
$o->g($a);
assert($a[0] == 2);

Objects are copied by „something like a reference“ more. This means the reference operator is not necessary for ojects (anlike PHP arrays)

Add some code to prove this.

Use error_log() for debug logging.

If the calling PHP script is run by the web server, the output usually goes to /var/log/httpd/error_log whereas if if the script is called from the command line, the output goes to stderr (tested).

• see also php-docu: capter „Using Php from the command line“
• /usr/bin/php can be CLI- or CGI- Sapi; test it with „php -v“
• Only If CGI:
  • Optin -qC is necessary in shebang; therefore use it BY DEFAULT! (-q suppresses header; -C keeps working dir)
  • set register_argc_argv = On in /etc/apache/php.ini

#!/usr/bin/php
<?php
echo "argument count: ".$_SERVER['argc']."\n";
foreach ($_SERVER['argv'] as $name => $value) {
    echo "$name: $value\n";
}
?>

Script saved as tester and called with tester bee fly prints:

argument count: 3
0: /home/becki/bin/tester
1: bee
2: fly

argv[0] = name of script
Dont't use $arc and $argv, because they are not available under all circumstances!

This is only useful for PHP command line scripts, not for webserver scripts.

Read stdin line by line:

while (fgets(STDIN)) {/* do some thing */}

printf(); 
echo;

/* writing to stderr 
   Note that STDERR seems only to be available when script is called from command line */
fputs(STDERR, "Some msg!\n");

See also logging

1. We want to intstall the lib somewhere under /usr/local/… to separate it from files of the Linux distribution
2. We don't want to interfere with the C libraries in /usr/local/lib/
3. The lib shall be easy to inlcude without the need for an absolute pathname.
4. We don't want to tweak the include_path in php.ini
5. Older code which uses the lib must not break when the API of the lib changes

Example with a self-written PHP library called mystuff:

• Install the lib in /usr/local/lib/php/mystuff0. This fulfills 1 and 2
• Make a symlink from a dir which is specified in the PHP include_path to the real lib, eg: /usr/lib/php/mystuff0 → /usr/local/lib/php/mystuff0. To find out what the include_path is, use phpinfo(). This fulfills requirement #3 and #4

phpinfo.php

<?php phpinfo(); ?>

The number appendix specifies the API version of the lib. When the API of the lib changes, then the version number must be increased. This is the case when exported functions are removed, when their behavior changes or when the signature of the function changes. Note that adding more functions (or classes) to the lib do not break the API.

With every new API you have to install a new lib and keep the older ones:

/usr/lib/php/mystuff0 -> /usr/local/lib/php/mystuff0
/usr/lib/php/mystuff1 -> /usr/local/lib/php/mystuff1
/usr/lib/php/mystuff2 -> /usr/local/lib/php/mystuff2

It should be ovious that you should avoid to change the API too often!

Note that in C you need not to specify a version number. This is resolved by the linker which seems to automatically write a reference to the newest lib into the binary at compile time.

Pre- and Postactions are probably obsolete. See http://skiclub-mitwitz.de/lib/libPage/

See also: Build your own MVC Framework

1. Every page must have exactly 1 unique pre-action (prefix) which is used for building the page eg a database query
2. Pages can only be accessed by their pre-actions not directly by other pages. If the page has no dynamic content, the pre-action just calls the page constructor or sets the $page global variable.
3. Although different pages may require to do the same things in it's pre-actions do not use the same action, but let those actions call the same helper function. Thus the target page becomes clear.
4. pre-action can change page by calling other pre-action

1. Each link or form of a page may be bound to exactly 1 unique post-action (suffix) eg a database update
2. Post-actions may be followed by pre-actions (chaining of actions)
3. Actions are named after the page they are bound to. To the name of pre-actions 'p_' is prepended and to post-actons (suffixes) 's_' is prepended
4. Use a parameter called eg 'target' for (the pre-actions of) pages wich can be called by differnt other pages and have to jump back to ther calling pages after they are left.

This section is in progress

• Google Buchsuche
• http://www.devshed.com/cp/bio/David-Web/
• Dokuwiki sourcode
• http://en.wikipedia.org/wiki/HTTP_cookie#Authentication
• http://pear.php.net/distributions/manual/pear_manual_en.html.gz#package.authentication.auth.intro

• Standard PHP Library SPL
• Check Auth, HTML_QuickForm2, Text_CAPTCHA, Validate of Pear
• Check http://www.devshed.com/cp/bio/Alejandro-Gervasio/
• Check out: Sending Email with PHP and Practical PHP: Sending E-mail
• Check active record pattern for database access