A Database-Driven Web Application in 18 Lines of Code
The LAMP combination of Linux, Apache, MySQL and a programming technology (typically Perl, Python or PHP) is a powerful one. Once you've built one Web-based database application, however, you've built them all. From a programmer's perspective, things become boring and repetitive pretty quickly.
I recently worked on my first Web application. I built it on Linux, of course, running through Apache and talking to MySQL. I used Perl as my glue language, with CGI figuring heavily. I created all the code to talk to a MySQL table, adding/editing/updating as need be. And it all worked, which was good. What was bad was, I was faced with repeating this activity (and effort) for each of the remaining tables in my database. In a time-honoured tradition among Perl programmers, I started to look for ways to be constructively lazy. There had to be a better way. After a few false starts and some searching, I found Maypole.
Initially created by Simon Cozens and maintained by Sebastian Riedel, Maypole is a rapid application development framework for Web applications. Maypole's home page promised a fully functioning application in about 20 lines of Perl code. This sounded too good not to try.
Having tried Maypole, I can confirm that Simon and Sebastian are not lying. Only a handful of lines of code is required to build a very functional application. Some setup is required, but—critically—this activity is not programming. Once the setup is complete, any number of applications can be created, each with a handful of lines of code. In the rest of this article, I step you through building an application with Maypole.
This step used to require an entire article to describe. Today, a single sentence summarizes. Pick your favourite distribution, and install it.
Having recently taken delivery of a new PC, I grabbed Fedora Core 3 and custom installed everything. If you don't have this luxury, be sure to install the following packages from your chosen distribution: httpd, httpd-devel, mod_perl, mod_perl-devel, mysql (client and server) and Perl.
Increasingly, modern distributions are shipping with release 2 of Apache and version 1.99 of mod_perl, as opposed to the entrenched 1.3.x release of Apache. Thankfully, Maypole can work with either release of Apache and also can be configured to use CGI (if mod_perl is not available). My Fedora installation shipped with release 2.0.52 of Apache and 1.99_16-3 of mod_perl, so that's what I use here. Users on the Maypole mailing list have reported successful installations on the vast majority of Linux platforms, including SuSE, Debian and Red Hat. Maypole also can be installed on Apple's Mac OS X and, with some extra effort, Microsoft's Windows.
As root, I edited Fedora's Apache configuration file at /etc/httpd/conf/httpd.conf and commented out the ServerTokens directive. I then arranged to start Apache automatically at boot time, and fired up the Web server using these commands:
chkconfig httpd on service httpd start
The lynx text-based browser can be used to check the status of the server with this command:
lynx -head -dump http://localhost/
The results confirm that Apache and mod_perl are up and running, as shown on the third line of this output:
HTTP/1.1 403 Forbidden Date: Wed, 17 Nov 2004 23:30:01 GMT Server: Apache/2.0.52 (Fedora) mod_perl/1.99_16 Perl/v5.8.5 DAV/2 Accept-Ranges: bytes Content-Length: 3931 Connection: close Content-Type: text/html; charset=UTF-8
Happy that all was okay, I re-edited httpd.conf and uncommented the ServerTokens directive, as it is best not to give away too much about the internals of your Web server to potential attackers. While in httpd.conf, I changed the ServerAdmin directive to a more appropriate e-mail address, then set ServerName to the DNS name for my server. I also made a note of the value set for DocumentRoot, which was /var/www/html on my machine.
Depending on the distribution you are running, MySQL already may be installed. If MySQL is missing, download it from your distribution's download area, or go to the MySQL Web site. On my Fedora machine, I issued the usual commands to prepare MySQL for use, while logged in as root:
chkconfig mysqld on service mysqld start
With MySQL running, I then set the MySQL administrator password:
mysqladmin -u root password 'passwordhere'
Free DevOps eBooks, Videos, and more!
Regardless of where you are in your DevOps process, Linux Journal can help!
We offer here the DEFINITIVE DevOps for Dummies, a mobile Application Development Primer, and advice & help from the expert sources like:
- Linux Journal
- New Products
- Flexible Access Control with Squid Proxy
- Users, Permissions and Multitenant Sites
- Security in Three Ds: Detect, Decide and Deny
- High-Availability Storage with HA-LVM
- Tighten Up SSH
- DevOps: Everything You Need to Know
- Solving ODEs on Linux
- Non-Linux FOSS: MenuMeters
- diff -u: What's New in Kernel Development