Oracle Database Tips by Donald Burleson

Installing PHP5, Apache and PEAR

This chapter is devoted to the installation of Apache, PHP5 and PEAR on Linux and Microsoft Windows 2000(R) platforms.  It gives a detailed description of installing each component on each operating system.

Because Apache 2.0 has been in production for more than a year at the time of this writing (February 2005), it has been selected as the version of choice for our purposes. Another reason for choosing Apache 2.0 are numerous reported problems with Apache 1.3 and the latest versions of PHP5 which were written explicitly for Apache2.

PHP5was installed as the Apache2 module, not as the CGI component. The CGI or "Common Gateway Interface" is an old standard that has been abandoned for years. CGI was the first attempt of creating a dynamic web content and has been replaced by a variety of mechanisms, such as ASP (Active Server Pages), JSP (Java Server Pages), and EJB (Enterprise Java Beans) with Servlets and application servers. 

Using a CGI component, the web server has to start a shell process or thread and execute the component the same way as an interactive user would. Shortcomings of such an approach are countless, ranging from performance problems (the shell process for each access has to be created, paged in, executed and then destroyed) to various security problems (many shell programs interpret reverse quotes as "in place command" whose output is stored into a variable, possibly leading to problems with commands such as rm -rf $HOME).

Executing PHP5 as a module means that the installation process creates a sharable library which is mapped into the address space of each Apache thread, thus becoming a part of the Apache server itself.  In other words, when PHP5 is installed as a module, Apache "learns" how to interpret PHP in addition to interpreting HTTP requests. No invocation of a shell interpreter is necessary; the code is efficiently shared and PHP will not interpret reverse quotes entered into HTML forms, as can be seen from the following picture:

The error at the top of the form reads as follows:

Exception:oci8 error: [12154: ORA-12154: TNS:could not resolve the connect identifier specified ] in CONNECT(`ls -l /etc`, 'SYSTEM', '****', )

When `ls -l /etc` was entered in the database field of the DBA_Helper, the expression was not interpreted as a shell command.  This limitation does not apply to the command line version, which will execute the command in reverse quotes as is visible from the following example:

Example 32

#!/usr/local/bin/php
<?php
   $A=`ls -l /tmp`;
   print "$A\n";
?>

When this command is executed, it produces the following output:

$ ./example32.php

total 240

-rw-r--r--  1 mgogala users      67951 Feb 26 21:21 fetchmail.log
drwx------  3 mgogala users       4096 Feb 26 02:08 gconfd-mgogala
drwx------  3 root    users       4096 Feb 26 10:12 gconfd-root
drwx------  2 mgogala users       4096 Feb 26 02:08 keyring-XPLgKk
-rw-------  1 mgogala users      58535 Feb 26 21:20 mailfilter.log
srwxr-xr-x  1 mgogala users          0 Feb 26 02:08 mapping-mgogala
drwx------  2 mgogala users       4096 Feb 26 21:27 orbit-mgogala
drwx------  2 root    users       4096 Feb 26 10:12 orbit-root
-rw-------  1 mgogala users        133 Feb 26 21:21 procmail.log
-rw-------  1 nobody  4294967295     0 Feb 26 21:27
sess_jjhh8ss4qqil5fd30cam6noca0
-rw-r--r--  1 mgogala users      54913 Feb 26 21:30 snap.jpg
drwx------  2 mgogala users       4096 Feb 26 02:08 ssh-llTnpa4746
drwxr-xr-x  2 mgogala users       4096 Feb 26 21:31 svao3.tmp
srwxr-xr-x  1 mgogala users          0 Feb 26 02:15 xmms_mgogala.0
-rw-------  1 mgogala users      11948 Feb 26 21:37 xses-mgogala.B3qoba


The command line version of PHP suffers from the same security problems as other scripting interpreters. It is, however, invaluable for testing and debugging PHP scripts.

Of course, Oracle must not be forgotten. The availability of an Oracle client is a prerequisite for using PHP5 with Oracle. On some supported platforms there is also a product called Zend Core for Oracle which is, essentially, a pre-built PHP environment which doesn't require Oracle client installed. More information about Zend Core for Oracle can be found on the Oracle Technology Network  at:

http://www.oracle.com/technology/tech/php/zendcore

Many bugs with PHP5 and OCI8 driver were fixed in the Zend Core for Oracle. Unfortunately, on Linux, Zend Core for Oracle is supported only on the commercial Red Hat and SuSE versions. If your version is not one of those, you  must build PHP from source.

 The Oracle server I use on Linux is Oracle 10g. Yet, on Windows 2000, I use the Oracle 9.2 client to access the database on Linux. The following two machines were used for testing the software and examples for this book:

• A no-name PC with a AMD Athlon 2000XP 1800MHZ, 512MB RAM, 200GB of disk space and the Red Hat Fedora Core 3 Linux operating system.

• A HP Vectra with a 233MHZ Intel CPU and 192MB RAM with the Windows 2000 operating system and 40GB of disk space.

The first machine was also used as an Oracle database server.

The remainder of this chapter covers the following installations:

• Installation of the Apache2 web server on Linux from the source

• Installation of PHP5 on Linux from the source

• Installation of PEAR modules on Linux from the Internet.

• Installation of the Apache2 web server on Microsoft Windows 2000 from the binary distribution.

• Installation of PHP5 on Microsoft Windows 2000 from the binary distribution.

• Configuration of PEAR software and installation of PEAR modules on Microsoft Windows 2000.

I chose to install Apache2 and PHP5 on Linux from the source instead of using the RPM or DEB distribution because while both Apache2 and PHP5 can be installed from the binary distribution, PHP5 has to be installed from the source if the OCI8 module is needed.  Installation of the Apache web server is extremely simple in both cases and only one program is needed to successfully install PHP5.

See code depot for complete scripts

This is an excerpt from the book Easy Oracle PHP.  You can get it for more than 30% by buying it directly from the publisher and get instant HTML-DB scripts from the code depot:

Easy Oracle PHP Create Dynamic Web Pages with Oracle Data Includes online HTML-DB code depot Buy it now for 30% off - Only $19.95

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