PHP
Programming Language, Scripting Language

PHP (recursive acronym for "PHP: Hypertext Preprocessor") is a widely-used Open Source general-purpose scripting language that is especially suited for Web development and can be embedded into HTML.

Contents

• Introduction
• Installation
• Configuration
• Examples
• Environment
  • Checks if Exists
• Error Handling
• Environment Variables
• mail - send mail (send emails)
• Problems and Solutions
• Shell Scripts in PHP
• Testing Scripts
• Macintosh Notes
• References

• Primary source: www.php.net
• Superb companion to MySQL database
• See also Server Side Includes (SSI) for other server side technology

Installation

Extract from php.net/manual/en/install.general.php:

In case of setting up the server and PHP on your own, you have two choices for the method of connecting PHP to the server. For many servers PHP has a direct module interface (also called SAPI). These servers include Apache, Microsoft Internet Information Server, Netscape and iPlanet servers. Many other servers have support for ISAPI, the Microsoft module interface (OmniHTTPd for example). If PHP has no module support for your web server, you can always use it as a CGI or FastCGI processor. This means you set up your server to use the CGI executable of PHP to process all PHP file requests on the server.

If you are also interested to use PHP for command line scripting (e.g. write scripts autogenerating some images for you offline, or processing text files depending on some arguments you pass to them), you always need the command line executable. For more information, read the section about writing command line PHP applications. In this case, you need no server and no browser.

A blog from 2012-09-03 blog.layershift.com/which-php-mode-apache-vs-cgi-vs-fastcgi describes differences between three variants (Apache, CGI, and FastCGI) and also a fourth (PHP FPM) is mentioned in comments.

string php_sapi_name ( void ): cgi-fcgi, 3

General research

• www.google.com/search?q=change+php+settings+in+htaccess
• www.google.com/search?q=php+server+api+differences
• www.sitepoint.com/how-to-override-php-configuration-settings/
• http://php.net/manual/en/configuration.changes.php

Specific modes research

1. Direct module interface (SAPI or ISAPI)
2. CGI
3. FastCGI
4. PHP FPM (FastCGI Process Manager)
• www.google.com/search?q=fpm-fcgi
• wiki.apache.org/httpd/PHP-FPM
• www.nginx.com/resources/wiki/start/topics/examples/phpfcgi/
• stackoverflow.com/questions/4526242/what-is-the-difference-between-fastcgi-and-fpm
5. cadium
   1. http://php.net/manual/bg/install.unix.caudium.php
   2. https://www.google.com/search?q=php+caudium
6. cli
7. cli_server
   1. https://www.google.com/search?q=cli_server
   2. http://php.net/manual/en/features.commandline.webserver.php
   3. https://stackoverflow.com/questions/28216015/passing-in-values-to-scripts-running-under-php-built-in-server
8. continuity
   1. https://www.google.com/search?q=php_sapi_name+continuity
9. embed
   1. https://www.google.com/search?q=php_sapi_name+embed
10. litespeed
    1. https://www.google.com/search?q=php_sapi_name+litespeed
11. https://www.google.com/search?q=php_sapi_name+milter

Configuration

• PHP in general
  • php.net/manual/en/ini.core.php
• 1&1:
  • How can I change my PHP settings? https://contact.1and1.com/solutions/95
  • Change PHP Directives - help.1and1.com/hosting-c37630/scripts-and-programming-languages-c85099/php-c37728/change-php-directives-a660257.html
    For Linux Web Hosting packages, 1&1 Managed Servers, and Linux Root servers. The following article describes how to change PHP directives by editing either the php.ini or .htaccess file.
  • View PHP Settings and Modules - help.1and1.com/hosting-c37630/scripts-and-programming-languages-c85099/php-c37728/view-php-settings-and-modules-a595886.html
  • Edit the Advanced Configuration for 1&1 Managed Servers - help.1and1.com/servers-c37684/dedicated-server-managed-c37686/edit-the-advanced-configuration-for-1and1-managed-servers-a612134.html
  • Disable PHP Global Variables - help.1and1.com/hosting-c37630/scripts-and-programming-languages-c85099/php-c37728/disable-php-global-variables-a708570.html
  • Modify the Apache Configuration - help.1and1.com/hosting-c37630/scripts-and-programming-languages-c85099/htaccess-c37776/modify-the-apache-configuration-a596185.html
  • google.com/search?q=1and1+php.ini+location
  • google.com/search?q=1and1+php+settings+htaccess

Examples

A few examples

<?php
print "<html><head><title>Hello, World! Script</title></head>\n";
print "<body>\n";
print "<p>Hello, World!</p>\n";
print "</body></html>\n";
?>

<?php
ob_start(); // start output buffer, => nothing's displayed until buffer's closed
phpinfo(1); // Show just general information (1)
$php_info .= ob_get_contents();
ob_end_clean();
$php_info = str_replace("</body></html>", "", $php_info);
$offset   = strpos($php_info, "<table");
print substr($php_info, $offset);
?>

Environment

Environment tests

Checks if Exists

Checks if something exists in current environment:

https://pear.php.net/

Error Handling

$my_error_reporting_enable = 1 (in script)

From php.net / manual / en / errorfunc.configuration.php (R:2016-02-29):

Some research

• How do I get PHP Errors to display? stackoverflow
• Reasons why PHP would echo errors, even with error_reporting(0)? stackoverflow
• how to display php error message on web page in firefox? stackoverflow
• PHP's white screen of death, stackoverflow
• php.net- Runtime Configuration - base for table above
• php.net- error_reporting() function
• php.net- Predefined Constants
• xdebug.org
  • xdebug.org/docs/all_settings
  • http://stackoverflow.com/questions/1758014/whats-the-difference-between-extension-and-zend-extension-in-php-ini

Environment Variables

how to get client's IP address in PHP - http://www.phpbuilder.com/board/showthread.php?t=10327697

reserved variables - http://ro.php.net/manual/en/reserved.variables.php

mail - send mail (send emails)

(PHP 4, PHP 5) mail — Send mail, man page: us2.php.net/manual/en/function.mail.php

mail() http://www.google.com/search?q=php+mail%28%29

( http://us2.php.net/str_replace )

Problems and Solutions

Until further notice, pls see Perl-section for more troubleshooting in general.

php-and-ssi.php - tests

Shell Scripts in PHP

If want to create scripts for use both in web server but also maybe occasionally as scripts.

!/usr/bin/env php
<?php

print "<html><head><title>Printenv Script</title></head>\n";
print "<body>\n";
print "Hello, World, in PHP";
print "</body></html>\n";
?>

Important details:

1) Shebang as first line
2) (Apparently) Also must have '<?php' .. '?>' also in scripts, to work what so ever.
3) Make sure executable (e.g. chmod a+x)

Note: Difference in how works on 1&1:

With '!/usr/bin/php ' as shebang:

(uiserver):uXXX:~/comgt-com/... > ./printenv.php
X-Powered-By: PHP/4.4.9
Content-type: text/html

With '!/usr/bin/env php ' as shebang:

(uiserver):uXXX:~/comgt-com/... > ./printenv.sh.php
X-Powered-By: PHP/5.5.30
Content-type: text/html

Resources:

• google writing shell scripts in php
• blog.digitalstruct.com/ 2007/04/24/ tips and tricks php shell scripts

Testing Scripts

Click to see how the web server handles different potential issues, details that may differ on different servers. All opens in a separate window (or tab).

More extensive tests of scripts are also avaiable in the Perl-section, including one page running a number of scripts (mostly Perl).

Older Material / Archive

Macintosh Notes

(Added 2009-09-08)

PHP is by default NOT enabled; to enable uncomment one line in httpd.conf and restart server:

...
# 2008-02-27 Wed: removing preceeding '#' from line below 
LoadModule php5_module libexec/apache2/libphp5.so


...

References

• General: www.php.net
  • Documentation: www.php.net/docs.php
  • PHP Manual - php.net/manual/en/
  • Language Reference - php.net/manual/en/langref.php
  • Security - php.net/manual/en/security.php
  • Features - php.net/manual/en/features.php
  • Function Reference - php.net/manual/en/funcref.php
  • ... (more)
• webcheatsheet.com/php/ - good overview, quick nav, web-based cheat-sheet - type
• Mac-specific:
  • <none yet>
• PHP Tutorial - Learn PHP: www.tizag.com/phpT
• For 10.4, older:
  • 10.4: Install Apache2, PHP5, and MySQL5 http://www.macosxhints.com/article.php?story=20051214031718251