Drupal's cache system is robust, feature full and extensible. It can be used to cache small blocks of rendered output or the results of more complex calculations. The cache can be stored in a for the page request, in a database or in a different cache system.

From the pages of 'crazy things you can do with Drupal 8' comes this idea that I recently had to implement on a site. This was on a site that had implemented translations, but they needed something a little extra. The central idea was that if you visited a page on the site in a particular language, and that language didn't exist, then to try and give the user a similar language.

For a long time the drupal_set_message() function has been a mainstay of Drupal development. You can use this function to print a message or an error response to a user. This is useful to do as it can be done almost anywhere before the final page rendering functions and will be printed into the same area of a Drupal page.

A while ago I was working on some changes to a website and came across a block of code that made me stare blankly at my screen. The website I was working on was a custom build website, created by another developer at the company I was working with at the time. I have never done a PHP:CSI on this site before but remember being so amazed at what I found at the time that I made a note of it for future reference. I have pondered recently how to approach the analysis of the code.

Colorising images is fairly simple to accomplish, especially using PHP's GD library. All we need to do is load an image, create a blank image of the same size in a particular color and then merge the two images together.

In fact, we can do this entirely with the imagecopymerge() function, but creating a function to wrap all of this makes sense as well.

From the drawers of "I didn't realise how complicated that was" I was wondering the other day how to draw a line using just pixels. This turned out to be more complicated than I thought.

Normally in PHP you would use the imageline() function to draw a line between two points. The following block of code creates and image and draws a white line from the coordinates 50x,50y to 200x,150y.

Part of the process of putting a new site live can be moving DNS entries around. Prior to doing this it's a really good idea to sort out the Time To Live (TTL) of the DNS record so that when you do change DNS entries you aren't waiting around for a day for the DNS to sort itself out. Most DNS registrars will allow you to set your TTL down to a minute or so.

It's also very important to check the status of your DNS records to ensure that they have the correct TTL, usually a day before (and day of) the move.

Whilst it is possible to view the contents of an SSL cert from within most modern browsers I occasionally find the need to use the command line to find out the same information. I find this useful when renewing certificates as browsers can occasionally cache certificates for longer than expected, causing false results.

The following command connects to the server, downloads the SSL certificate from port 443 and then uses the openssl tool to extract the information from the certificate into a readable format.