Post-Module PHP Forms

BTM 395: Internet Programming

Cookies• Cookie is a name-value pair stored on the

user’s (client) computer– Track preferences and other information

• Each server’s cookies stored as a text file on client computer– Stored securely so that it is difficult for other server-

side applications to access another’s cookies– But don’t store sensitive information (e.g. credit card

number) without encryption• Security risk if someone has physical access to the user’s

computer

• Write or change cookies:– setcookie( $name, $value ); various optional options

(e.g. expiration date)• Read cookies

– Use the $_COOKIE['name'] environment variable

Sessions

• A session is a built-in way of tracking a user across multiple pages

• Implemented using cookies• Thus, requires cookies to be enabled on client

side

PHP string quoting• ' (single quote): for literal strings with minimal

text expansion (\\ and \' only)

• " (double quote): for flexible strings with expansion of variables and many codes (e.g. \n and \t)

• Heredoc: for lengthy strings with complex plain-text format (see http://codepad.org/pzHHK3wH) – Begins with <<<ANY_DELIMITER– Ends with ANY_DELIMITER; as the only contents of

closing line– Expands variables similarly to "– Nowdoc format works like single quote equivalent of

heredoc• Official reference: http://

php.net/manual/en/language.types.string.php

Array indexing

• ALL arrays in PHP are associative arrays• Numeric indices are automatically

generated, but the arrays are still fully associative

• Arrays can have both flexible associative keys and auto-generated numeric keys

• Official reference: http://www.php.net/manual/en/language.types.array.php

Customized array sorting

• PHP has many built in array sort functions, for sorting by value, by key, and backwards

• JavaScript only has one very limited built-in sort: lexicographic (strict alphabetic) sort

• Both have custom sort functions that work similarly– JavaScript: myArray.sort(function(a,b){…});– PHP: usort($myArray,customSortFunction);

customSortFunction(a,b){…};– These can sort any kind of array anyway

you like, including multidimensional arrays

Other PHP tips

• Equality and assignment= vs == vs ===

• The ternary (conditional) operator ? :– $myVar = $testCondition ? $valueIfTrue :

$valueIfFalse;– Ternary operator exercise

• Stop an infinite loop in PHP– Click the stop or cancel button on your browser to

stop the page loading– Or just wait 30 seconds or so for a server timeout

Sources

• Heredoc example: http://www.tuxradar.com/practicalphp/2/6/3