PHP Reference: Beginner to Intermediate PHP chapter 1 Class 2

PHP Reference: Beginner to Intermediate PHP5

If multiple pages will see the same functions, then make a different one

functions.php file (name it whatever you like) and require() or
require_once() with pages that will need to use those functions. For speed

and file size, page specific functions should be included directly on the
necessary page.

exit([$string])

die([$string])

Stops the current script and outputs the optional $string.

Example:

$result = @mysql_connect('db', 'user', 'pw')

or die('Unable to connect to database!'); echo 'If it fails, this will never be seen';

Unable to connect to database!

Note: The above output would only display if it failed. If the @ was not present before mysql_connect(), PHP would output a warning as well.

eval($string)

Evaluates a string as if it was code. This can be used to store code in a database and have it processed dynamically by PHP as if it were part of the page. All appropriate aspects of code must be included, such as escaping items with a backslash (\) and including a semicolon (;) at the end of the string.

Example:

$name = 'Mario';

$string = 'My name is $name.'; // Note the single quotes echo $string;

$code = "\$evalstring = \" $string \" ;";

// Effect of backslash escape: $code = "$evalstring = " $string " ;"; eval($code); // eval($evalstring = " My name is $name " ;);

// $evalstring is the same as $string, except with double quotes now echo $evalstring;

My name is $name. My name is Mario.

sleep($integer)

Pauses PHP for $integer amount of seconds before continuing.

Example:

sleep(2); // pause for 2 seconds

usleep($integer)Pauses PHP for $integer amount of microseconds before continuing.

Example:

usleep(1000000); // pause for 1 second

uniqid([$scalar [, entropy]])

entropy – [optional] $boolean default: FALSE, 13 character output

Generate a unique ID based on the $scalar. If no input is given, the current time in microseconds is used automatically. This is best used in combination with other functions to generate a more unique value. If the $scalar is an empty string ('') and entropy is set to TRUE, a 26 character output is provided instead of a 13 character output.

Examples:

$id = uniqid();
echo $id;

47cc82c917c99

$random_id = uniqid(mt_rand());
echo $random_id;

63957259147cc82c917cdb

$md5 = md5($random_id);

echo $md5;

ea573adcdf20215bb391b82c2df3851f

See Also:

md5() – MD5 algorithm based encryption

setcookie(name [, value] [, time] [, path] [, domain] [, secure] [, httponly])

name – $string
value – [optional] $string

time – [optional] $integer default: till the end of the session
path – [optional] $string default: current directory

domain – [optional] $string default: current domain (e.g.
http://www.example.com)

secure – [optional] $boolean default: FALSE, does not require a secure connection

httponly – [optional] $boolean default: FALSE, available to scripting languages

PHP Reference: Beginner to Intermediate PHP5

Sets a cookie2, visible to the server on the next page load. To send then default value, use a set of single quotes ('') for each argument you want to skip except the time argument, which should use 0 to send the default value. In most cases, providing the name, value, time, and domain will cover most uses (with '' for path).

Examples:

setcookie('Cookie','Set till end of this session',0);

// This will display properly after the page has been reloaded print_r($_COOKIE);

Array ( [Cookie] => Set till end of this session )

setcookie('Cookie','Set for 60 seconds for all subdomains of example.com, such as www., mail., etc.',time()+60,'','.example.com'); print_r($_COOKIE);

Array ( [Cookie] => Set for 60 seconds for all subdomains of example.com, such as www., mail., etc. )

Some common times used for expiration: time()+60*60*24 is equal to 1 day time()+60*60*24*30 is equal to 30 days

time()-1 is one second in the past, used to expire/delete a cookie

setcookie('Cookie','',time()-1);

// expires the Cookie named 'Cookie'. Note the empty string for value

urlencode($string)

Changes the formatting of $string to the proper format for passing through a URL, such as part of a GET query, returning the new string.

Example:

$string = 'Hello There! How are you?'; echo urlencode($string);

Hello+There%21+How+are+you%3F

urldecode($string)

Changes the formatting of $string from the URL compatible (such as a GET query) format to human readable format, returning the new string.

Example:

$string = 'Hello+There%21+How+are+you%3F'; echo urldecode($string);

Hello There! How are you?

Must be sent prior to any headers or anything else is sent to the page (including the <html> tag). See ob_start() for an easy way to make this work

get_magic_quotes_gpc()

Returns 0 if it is off, 1 otherwise.

Used to determine if magic quotes is on. This check is used for code portability and determining if the addition of backslashes is necessary for security purposes and preventing SQL injection. Magic_quotes_gpc processes GET/POST/Cookie data and, if turned on, automatically processes the above data every time with addslashes().

Example:

if (get_magic_quotes_gpc()){

echo 'Magic Quotes is on!';

}else{

echo 'Magic Quotes is NOT on, use addslashes()!';

}

// This is the default setting for PHP5 installations Magic Quotes is NOT on, use addslashes()!

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