How to hack a WordPress plugin that doesn’t have the filters you want

The best thing about WordPress, besides the fact that nearly anyone can edit a website built with it, is hooks. Filter and action hooks allow developers like me to customise a WordPress website in myriad ways. Many good plugins provide hooks too. But inevitably, you'll run up against a problem where you'd like a plugin to have a hook that it just doesn't have. You can ask the plugin author nicely to add that hook, and maybe they'll add it sometime soon, maybe even on time for your deadline. But what if your deadline comes before they add it?

Different thumbnail sizes for NextGEN Galleries

Ok, so we're allowed to have one (1) size option for thumbnails in all galleries, and they can be either cropped square, or not. This is my only option? But what if I want to have a gallery page of all of the lovely staff for my clients website, and their photos have been sensibly taken in portrait format, I do NOT want the thumbnails for this gallery to be cropped, that would be just wrong. And then there is to be a page with a photo gallery of the staff picnic where people have enjoyed taking happy snaps in both landscape AND portrait formats because that is what suits, so I need these thumbnails cropped.

Filter invalid characters from XMLReader input files

I just ran into a problem reading XML data exported from a Microsoft Access database. For whatever reason, Access has written VT (vertical tab) characters in the XML, which PHP's XMLReader baulks at. To be able to handle that on each data load without requiring the user to edit their XML, I wrote a simple PHP stream filter that replaces each VT character with a LF (line feed).

Sort wp-e-commerce products by category and product title

The wp-e-commerce shopping cart plugin lets you sort your products by a few different things: name (product title), price, date/time created... but it doesn't let you sort by category name and then product title. Here's what I just came up with for one client; it isn't generic, but other developers should be able to adapt it for their circumstances.

Running QEMU with port redirection through libvirt

Like many developers these days, I use a bunch of different virtual machine images to give me access to multiple development and test environments without having a room full of computers. My VM of choice is QEMU KVM, the kernel-based virtual machine bundled with Fedora. I've always used simple shell scripts to start my VMs, which has allowed me great flexibility, but yesterday I set one up using the nice Virtual Machine Manager (VMM) GUI application. And remembered why I wasn't using it: there's no way to tell it how to do TCP port redirection! But now, there is a way...