PHP

Server-side scripts.

file.php

Contains normal HTML, and then PHP code mixed in, delimited as follows:

<html> <body> html code <?php php code ?> more html code

PHP gets interpreted on server side before resulting HTML stream is returned to client.
Client can't see PHP code: Unlike the case with Javascript, client can't see the code that generated the HTML.
PHP used for interaction with data on server (e.g. database).

Reference

Environment and calling programs

to display structure of variable:

	var_dump($variable);
	print_r($variable);

Predefined Variables
- $_SERVER
- to see incoming environment variables:
  - var_dump($_SERVER);
To see local configuration of PHP, set up a test.php page that does:
- phpinfo();
accessing command-line:
- exec
- shell_exec
- backquotes
- system
- passthru
- e.g. Could access command line to do HTTP request.
Make HTTP requests directly
- file_get_contents
- HTTP extension
- cURL extension
- Might be issue with DCU proxy.

Example

My demo PHP server-side page illustrates some environment variables etc.

Just put in your normal webspace. Only needs read permission, not executable.

PHP mini test

Return a single environment variable:

REMOTE_ADDR
HTTP_X_FORWARDED_FOR

Call with arguments

PHP can be used with arguments in the URL.
This is like a CGI script with HTTP GET, like a Google search.

http://host/prog.php?variable=value

Example:

world.php?world=w2m.TyrrellWorld

Parsed like this in world.php:

<html> <?PHP $qs=$_SERVER["QUERY_STRING"]; parse_str ( $qs ); // $world is now defined as whatever the value was ?> <head> <?PHP print "<title> World: $world </title> \n"; ....

Stand-alone PHP scripts

Can use PHP as just general offline scripting language.
Can run Stand-alone PHP scripts at command-line. Something like:

#!/usr/local/bin/php 

Whatever is outside PHP is just displayed.

<?php

// echo PHP_VERSION;

 print "Name of script = $argv[0] \n"; 
 print "First command-line arg = $argv[1] \n"; 

 print "All command-line args: \n";
 print_r($argv); 
 print "\n"; 

?>

Whatever is outside PHP is just displayed.

On DCU Linux, this works for ssh login:

#!/local1/php5/bin/php