albert wavering bobby seng. week whatever: php announcements/questions/complaints
TRANSCRIPT
ALBERT WAVERINGBOBBY SENG
Week Whatever: PHP
Announcements/questions/complaints
What is PHP?
Server-side scripting language PHP: Hypertext Processor Created in 1995; current version
5.3.3 Dynamically typed (like JavaScript) Other scripting languages:
Microsoft ASP Adobe ColdFusion Java (using JSP) Ruby (using Rails)
PHP
Scripts are stored on a server Interpreted on servers when a page
is requested I request example.php Server looks up the file PHP software processes PHP file Output is HTML+CSS+JavaScript that is
returned as the requested page
Real Life Examples
Facebook ‘Compressed’ PHP
Wikipedia Photobucket Yahoo! YouTube
PHP
Can run on most operating systems Compatible with most servers
(Apache, IIS, etc) Lets you create dynamic webpages
Most useful when you want to insert specific custom data
Where does this data come from? Databases!
PHP + MySQL
MySQL is a Structured Query Language database platform
PHP has native built-in support for MySQL
While interpreting a PHP script, PHP software can make multiple requests to multiple MySQL databases
PHP also supports many other databases
PHP Basics
PHP Script can contain: HTML CSS JavaScript PHP script
PHP files have extension .php If you save them as .html, the PHP
software will not process them Closed source – your users cannot
read your code (unlike JavaScript)
PHP Basics
PHP scripts are written inside a <?php ?> tag
Anything you want interpreted has to be inside these tags
Example:
<html><body>
<?phpecho "Hello World";?>
</body></html>
PHP Basics
Like Java, every line in PHP ends with a semicolon;
//Single-line comments /*
Multi-linecomments*/
PHP Basics
PHP variable names are always preceded by a $
Assigning a value to a variable:$variable_name = value;
PHP variables are loosely typed Don’t have to declare variables before
using them Can reassign variables to hold different
types of values
PHP Basics
Variables can only include alphanumeric characters and the underscore
Variables must start with a letter or an underscore
PHP variables have a single scope, usually Variables in functions are limited to those
functions The keyword global will use global variables
inside a function
The global keyword
<?php$a = 1;$b = 2;
function Sum(){ global $a, $b;
$b = $a + $b;}
Sum();echo $b;?>
Operators
+ Addition +=- Subtraction -=* Multiplication *=/ Division /=% Modulus %=++ Increment-- Decrement= Assignment.= Concatenate (Strings)
Comparison Operators
== Equal to!= Not equal to <>< Less than<= Less than or equal to> Greater than>= Greater than or equal to
Logical Operators
&& and AND|| or OR! not
xor XOR
If/elseif/else
if (condition)statement;
elseif (condition)statement;
elsestatement;
Switch
switch(variable){case a:
statement;break;
case b:statement;break;
default:statement;
}
Loops
while (condition){statements;
}
for (initialization; condition; increment){statements;
}
Arrays
Numerically indexed Associatively indexed (maps) Multidimensional (combination of one or
any of the above) Create an array with $var_name =
array(); Index with $var_name[0] = assignment;
or$var_name[$other_var] = assignment;
PHP GET
Built-in functions to get data from pages $_GET function collects values from a form sent
with method = getHTML Page:<form action="welcome.php" method="get">Name: <input type="text" name="fname" />Age: <input type="text" name="age" /><input type="submit" /></form>PHP Response:Welcome <?php echo $_GET["fname"]; ?>.<br />You are <?php echo $_GET["age"]; ?> years old!
PHP POST
Get is limited to 100 characters Not awesome
Post has 8Mb maximum Awesome
PHP Post
HTML Page:<form action="welcome.php" method="post">Name: <input type="text" name="fname" />Age: <input type="text" name="age" /><input type="submit" /></form>PHP Response:Welcome <?php echo $_POST["fname"]; ?
>.<br />You are <?php echo $_POST["age"]; ?> years
old!
Resources
Ask Jeeves AltaVista http://php.net/manual/en
Language Reference Your new best friend
Code examples, user questions, hints
http://www.w3schools.com/php/default.asp
Homework
Create a PHP script that outputs the current date to a page, inserted among other usual HTML elements in a full page http://php.net/manual/en/function.date.php
Use one additional construct of PHP (array, loop, if/else, etc)
Upload to your account on my server as a .php file by the start of next class
Be creative! Databases next time (real fun starts)