Safely overriding core modules to make them do what you need or want.
Sometimes a module presents things on screen in a way you don’t like. It might be that a certain piece is missing or the order of the elements breaks something you are trying to do. This guide presents some techniques for working around this.
Readers are assumed to be comfortable editing templates and identifying the source of content by searching the Zotonic codebase.
If you want to just change the look and feel, you should be able to get most of the way with CSS: create a CSS file in your site, and override the styles you don’t like.
Failing that, you should try overriding templates: Copy the module’s templates into your own site/module, keeping the file name and relative directory intact.
Make sure that the priority of your site is higher than the original module! To view this, check the prio field in the module overview in the admin, this should be a lower number. e.g. 1 has higher prio than 500.
In extreme cases, you can copy the module into the modules directory of your site and rename it. Make sure to change the module attributes within the Erlang modules along with renaming the files themselves.
A case for this would be an outdated core module that no longer works with an API or protocol due to external changes. For example, if Twitter dropped their current streaming interface (unlikely) then you might need to copy and modify mod_twitter in order to bridge the gap until you submit a patch and its gets accepted.