I was recently working on a project which required me to insert external, dynamically generated, HTML code into a HTML page. The dynamic HTML code was being generated with PHP, as it was extracting data from a MySQL database for display. So people would be able to paste some static code into their page and this code would reference an external file on a remote server which would return content.
One of Wordpress’ greatest features, which has undoubtedly contributed to its great success, is the plugin system. Plugin developers use the action and filter hooks offered by the plugin API to tap into the Wordpress system, without the need to hack the core code.
Whilst the list of action and filter hooks offered is substantial and affords much modification freedom, there are going to be times when there is no action or filter to do the job. I was recently asked to develop a plugin that added a few small things to the Wordpress administration backend. A quick browse of the plugin API led me to conclude that there was no plugin hook available which would directly enable me to modify the area in question. So I was about to edit the relevant core Wordpress files when I realised that I could end up indirectly using a plugin hook after all.
