Drupal

I was struggling with a problem on a Drupal 8 project that was in development recently where a block used to show information to anonymous users was cached for the first user who saw it. This meant that the special message meant for the first user was then being seen by all subsequent users who visited that page. This only happened when page caching was turned on, but as it's best practice to do that I didn't want to turn that off just to solve one little problem.

For the past few months I have been organising an unconference event with †he other organisers of the North West Drupal User Group (NWDUG). An unconference is just like a normal conference, with the exception of the sessions. All of the sessions are selected on the day and then presented by the delegates. Thankfully, everything came together and on November the 4th at MadLab in Manchester we had 55 people show up for the day. Once we introduced the day and got some sessions on the wall we started out.

I had to update a Drupal 7 site recently and needed to change the field keys of a list field to be different values. This wasn't possible from within Drupal as it does a pre-check to make sure that the key doesn't already exist. If it finds any values present in the database with that key then it will reject the change. This is absolutely correct but causes a little bit of an issue when you need to update these values.

The solution to this is to alter both the field definition and the field data via directly altering them in the database. The following function provides a neat little way of doing this to a field by just passing in the field name and what the key values need to change to.

The European DrupalCon was held in Dublin from 26th - 30th September and I went along with a couple of colleagues to learn a few things about Drupal. I have been back from the conference for a few days now, and I wanted to write down some of the highlights of the conference in a blog post. There is a lot going on at DrupalCon and with 2000+ people, 3 full days of sessions, 2 tutorial days, multiple parties and over 10,000 cups of coffee consumed there is too much to write about here. So this will be a few random highlights and stand out moments of the conference.

I was recently asked to implement a feature on a Drupal site where all nodes of a certain type would redirect to a main listing page if that node had been unpublished. The problem in doing this is that if a post is unpublished then Drupal will issue an access denied response quite early on in the boot process. When the menu item is loaded it goes through an access callback which sees that the post is unpublished and issues an access denied before anything else can happen. So in this situation you can't use things like Rules to redirect users as the rule is never triggered.

The solution was to use hook_menu_alter() to change the access callback parameter of the node page. We are essentially replacing the normal access callback of node_access() with our own version.

To get the currently selected language on a Drupal 8 site you need to run the following.

When creating re-usable theme templates in Drupal 8 it's quite easy to include that template by using the following snippet.

{% include directory ~ '/templates/parts/footer.html.twig' %}

This assumes that your footer.html.twig template file is kept in the same theme as the template you are working on. It's also good practice to add the template part to a directory called 'parts' or 'components' to separate them from the normal Drupal templates.

When overriding theme functions in Drupal 7 you would normally copy the theme function into the template.php and alter it to suit your needs. This isn't always convenient though, especially if you are trying to abstract functionality into modules and not have code in your theme layer that is reliant on module code. If you add theme override functions to your module files then they won't do anything as Drupal isn't looking for them there and won't pick them up.

It is possible to alter the theme registry in order to get Drupal to pick up your theme functions from your module code. This helps collect together code that performs a certain task and allows you to deploy theme alterations along with module updates.