tryGit: it’s the teach, not the tech.

I picked up a link to a free online course from a recent Linux Voice podcast. I tried the course and wasn’t really impressed with it. The interface is nice, with an embedded virtual terminal to let you practice typing in the commands but the pedagogy is pretty weak. There’s nothing in the presentation that indicates that the designers understand how to construct understanding: all this lovely bit of code is doing is rehearsing a list of commands (and there’s even a click-once shortcut if you can’t be bothered actually typing). It’s more of a checklist than a course. It would be easy to turn it into a really effective bit of online learning with the addition of some better structure and graphics, and maybe a little assessment for learning. A shame, really, as it is clearly a loss leader to sell the Code School itself: I am in the market for some good quality online learning in their area, but I’m not likely to look any further at their catalogue.

CentOS 6.5 on MSWind

Rather than make a pig’s ear out of my live VPS by testing out new Ruby code I’m playing with, I thought it would be prudent to have a machine that I can break without upsetting users. I have an Atom-based Advent netbook which only ever gets played with occasionally and this afternoon, seems quite willing to volunteer for a rebuild as a CentOS server. The world loves a volunteer. Continue reading “CentOS 6.5 on MSWind”

Code hacks: Internet Explorer Compatibility mode

guess-browserI’ve been developing a site for a national competition to be launched in October and ran into a little difficulty with Internet Explorer. Despite this browser losing ground amongst even the unthinking default user community, it is still sufficiently popular that I needed to look at the problem.

The site is running WordPress on a LAMP server using Konstantin Kovshenin‘s Expound theme. One of the testers noticed the letters “Ski” next to the Home menu item. Mousing over it produces a fleeting grey box to appear top left of the browser window. This turned out to be only visible in IE8, IE9 and IE 10 in “compatibility mode”, a feature of IE that allows the browser to render sites that are broken by IE’s shockingly poor implementation of standards, using a model from an earlier version. It’s what a code monkey might call a Kludge.

SkiThe “Ski” is in fact, the first few letters of “Skip to content”. It is one of several features of the site’s theme implementation which are broken in IE’s compatibility mode.

There are several suggestions in the forums designed to force IE into non-compatibility mode and render the site properly. Most rely on delivering a <Doctype> tag on the very first line, followed immediately by a X-UA-Compatible meta tag. Unless this tag is placed on the line immediately after the Doctype tag, IE ignores it.

I considered trying to knock up a plugin to make this work in some kind of customisable way. Editing the theme’s header.php file seemed doomed to be overwritten on the next update, and branching a child theme felt like too much hard work for such a small fix to accommodate a browser that I personally would like everyone to stop using. Part of me wants all sites to look broken when viewed with IE so as to encourage the masses to make an intelligent choice for once. Let’s not start talking about democracy.

Anyway, a little more digging found a really elegant solution which suited my particular needs from Reza Qorbani, which is to use the .htaccess file to have the Apache server sniff the browser and send the metatag. This is what I finished up with:

BrowserMatch MSIE best-standards-support
Header set X-UA-Compatible IE=edge env=best-standards-support

It works a treat. Thanks, Reza!

Pro Git and more MX DNS

Continuing the summer of code into the early autumn, I have been developing, enhancing and debugging the new server. New and migrated sites are stable and responding well within the resource limits I’ve chosen of 10GB disk, 50GB traffic (although we’re close to whacking this one) and 256/512 MB RAM/Swap space. Uptime has been 100% for over 60 days now.

Within the suite of services running on the server are database, web server, CGI, mail, stats and monitoring. What is not, is the DNS service, which I have learned to keep in a different place, with the registrar. Setting up reverse DNS for the mail service to work correctly is important: I discovered that one client had been having difficulties receiving mail from just one of his friends. This was because the MX DNS entry for his domain pointed to an IP address which some service providers will reject as it doesn’t comply with the RFC. Changing it to the host domain of the server’s IP, however, stopped all mail getting through to the client. This was finally resolved by pointing the MX record for the domain to the domain itself:

example.com. A     192.0.2.1
@            MX 10 example.com.

If you want to know how the Internet works, by the way, a really good place to start is the Internet Engineering Task Force (IETF). They have a good introduction here. Many internet standards are defined in RFC documents.

Other services on the server operate as database-driven php suites such as the WordPress CMS, Moodle, LimeSurvey or phpBB. All of these are subject to modifications, code hacks and tweaks to make them work to the needs of the site owner. Whilst the Parallels Plesk Panel allows install-at-a-click for many application suites, I prefer to manage the installation and customisation of these myself. Until now, I had used the download-unzip-upload over FTP method but I’m going to try using the more elegant command-line facility offered by Git. I’m getting started by using their excellent online documentation. This should allow me a much faster update route and potentially a way to be a better contributor to open source than the consumer I have been.