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So you are installing a modern version of php using one of the alternative repositories, and suddenly you are confronted with a confusing choice. You want support for mysql (mysqli or PDO-mysql) in your php program. But which one to choose?

First off, you should probably be using PDO. It's just a cleaner database interface when compared to mysqli, and also tends to be the supported option if you're using an ORM like Doctrine2.

But you probably have found that installing the PDO package doesn't get you support for MySQL.

So what are these 2 packages? Well let's see what yum under Centos shows us, once we've setup webtatic as a repo:



In short, the mysql extension aka the mysql library is to quote Oracle/mysql

... a general-purpose client library

named libmysql.

This was the original php approach to supporting mysql. MySQL provided a client api library, and using that c library, a php extension was created that depends upon libmysql implementing the famous mysql_ functions that allowed php to talk to mysql.

The mysqlnd package (where nd stands for "native driver") is the fruit of a project to make mysql work optimally in the php language. Again to quote the mysql site:

The mysqlnd library is highly optimized for and tightly integrated into PHP. The MySQL Client Library cannot offer the same optimizations because it is a general-purpose client library.

The mysqlnd library is using PHP internal C infrastructure for seamless integration into PHP. In addition, it is using PHP memory management, PHP Streams (I/O abstraction) and PHP string handling routines. The use of PHP memory management by mysqlnd allows, for example, memory savings by using read-only variables (copy on write) and makes mysqlnd apply to PHP memory limits.

On top of these benefits are a number of interesting enhancements and support for plugins that might be of specific interest to you as a developer or sysadmin.

In general nothing should break in your code as the api should work the same under mysqlnd as it did with the old mysql library.

Conclusion

In summary, you want to use mysqlnd now and in the future.

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A PHP block is started with the tag <?php. However, there is also an alternative known as a "short open tag" which is to only use <?

The problem with using short open tags is that they conflict with xml parsers and for that reason, support for short open tags has to be enabled. By default, it's disabled and enabling deprecated features may be impossible if hosts don't allow it.

Every so often you may come upon a code base that was written using short open tags.

Often people are first confronted with this problem when they have a legacy code base, and either move it to a new server or upgrade php only to find that the site is spewing errors and no longer functional. In a worse case scenario portions of your php code will be plainly visible to end users due to the fact that the php parser is no longer parsing those blocks and simply returning them as html text.

There are a number of different approaches you can take to solve this problem. First you can turn on the support for short open tags, but as I mentioned previously, this is not recommended.

Continue reading "Fixing PHP short open tags" »

I've been helping out Scott McGinnis with a revamp of his web-videos-for-kids and tweens site, Global Broadcast 4 Kids, aka GB4K.com.

Scott was a pretty successful actor in the 1980's, who transitioned to directing in the 90's, and like a lot of directors in Hollywood, got his first chance behind the camera courtesy of Roger Corman. After a stint making low budget features, he went on to direct episodes of "Angel" and the TV series "Honey I Shrunk the Kids", and for the last few years, has been producing educational webisodes using Prosumer video equipment, and editing the episodes on a Mac with Final Cut Pro.

The subject matter and production values aren't that much different from what you might expect to find on basic cable networks like The History Channel or Disney Channel. The GB4K "twist" is that all the segments feature kids and teens as the newscasters, reporters and narrators. GB4K has already proven to be a great training ground for a number of its young "stars", as GB4K alumni have gone on to success at the Disney Channel, and in feature films. There's lots of material in the archive, and he creates a number of new episodes each week, from sports and entertainment news, movie premier "red carpet" interviews, how-to videos on dancing and skateboarding, history channel-esq features on subjects like Guitars and Merry-go-rounds, and environmental science and the latest in Green living practices and Green news. The site also includes music videos he directed and produced for Amber Lily and Jadagrace Berry. A great example of what Scott is able to accomplish as a one-man directing, production and post production crew, is the Jadagrace "Express Yourself" video, which in my opinion compares favorably with music videos costing 10-20x as much.

Despite having a substantial library of video content, frequent updates, and a clear cut audience, problems with the website had put GB4K into a holding pattern.

Continue reading "Profile of the GB4k.com launch -- Joomla reborn" »

One of the first things people learn about using subversion is how to do a "checkout" using svn co. The svn checkout command pulls files from the subversion repository into your "sandbox" and in so doing creates what subversion calls a "working copy". A working copy includes a .svn directory in every subdirectory of the working copy, which is chock full of directories and files that svn uses to determine what you're doing in your sandbox.

A "working copy" is designed to be just that -- a copy of the source tree built with the assumption that you will be making changes and committing them back to subversion. But what do you do if you want the files, but you don't need or want a sandbox?

Continue reading "Get files from subversion without creating a sandbox using svn export" »

*Part 1 of this series is here*

Customizing your LAMP server

Unix people are probably familiar with the father of the DNS system -- the /etc/hosts file. The hosts file has a simple format:

ipaddress hostname

In the days prior to DNS, people would update a master hosts file and copy it around to all the servers in the enterprise. Surprisingly Windows versions also support this file, as a way of overriding DNS, so we can use this to our advantage, by adding an entry for our development server. In this example, I'm going to use dev.gizmola.com, which is not a real server.

One important reason to do this is that Apache and other web servers, use a feature of HTTP 1.1 that specifies a header field named "Host:". This mechanism facilitates the service of multiple domains from a single apache server, through the configuration of apache virtual host (or vhost) entires. The server uses the Host name in the HTTP header to determine how to route requests, so without host name resolution. you have to use non-standard ports and other mechanisms that are more trouble than they're worth. a

Continue reading "Centos Virtual LAMP server -- Part II" »

A few years ago I published a 3 part LAMP tutorial series entitled LAMP, MySQL/PHP Database Driven Websites on the well known php community website PHPFreaks.com. This series dealt with a slew of practical issues including how a LAMP server works, relational database design using MySQL, many to many tables, SQL inner and outer joins, practical PHP debugging, php documentation tools, basic PHP classes, css, interactive javascript & DHTML with a chooser widget, php HEREDOC and php basics like how to process forms and utilize GET and POST methods.

The series was fairly successful, (a 4.5 of 5 after hundreds of ratings), many pages of comments and questions, and page views to the 100k's+ although PHPFreaks auditing system was turned off at some point and stopped recording views.

Unfortunately, some years ago PHPFreaks.com suffered some fairly catastrophic issues with its publishing system. There were also some bugs, and the site was exploited with some XSS, and the admins simply decommissioned the majority of the site. My series was part of what disappeared. At that point, a couple of college Computer Science courses on web development had taken the series and integrated it into their curriculum, and the professor of one of these courses had converted it into a Word document, which I was able to download and convert to pdf.

I plan to write a compatible publishing addon for gizmola.com so that I can take the original markup and republish it here, but in the meantime, here is the series in pdf format. The conversion utility they used stripped out the original markup, and page breaks are gone, but the text, source code, and illustrations are all still there.

I also offer all the source code for parts 2 & 3 of the series. I'm not sure what happened to the source for part 1, however, it is all included inline in the tutorial. The LAMP, MySQL/PHP Database Driven Websites series is now available in pdf format. Click here.