The next step following the database integration is a simple settings page to change the plugin options. This is achieved with another hook to add an item to the menu in the admin area:

This alone doesn’t do anything other than telling WordPress to call the ‘Admin_Menu’ function at the right time, the function then tells WordPress the menu item to add and which page to open via the add_options_page API function:

This creates the page link on the menu as ‘Thumbshot Preview’ and informs which file (the current plugin PHP file) and which function to call ‘Admin_Settings’. The number 8 refers to the user level required to access the page, in this case it is only available to the WordPress admin.

The Admin_Settings function simply outputs some HTML and also provides some very basic form validation and obviously also does the database updates. I have copied the styles and layouts from a standard WordPress settings page to ensure my page is consistent with the default styles. Here is the completed function:

The validation here isn’t perfect, but it does the job. Considering the simplicity of this plugin it doesn’t really make much sense to spend time making it any more complex than this. It would be nice to use templates for the HTML as well but again as this is a simple plugin it doesn’t really warrant the complexity.

Here is a screen shot of the settings page:

Note: The functions listed here are used as part of the object defined in my previous post.

The next step with the plugin is to add some database integration so the plugin options can be stored in the WordPress database. This is really simple as the API provides funtions for this in the form of the functions add_option, get_option, update_option and delete_option.

To ensure that the database is populated with some defaults, a hook can be added to do this:

This will be triggered when a user installs the plugin and the default options will be saved to the WordPress options database.

I have also added a deactivation hook to clean up the options from the database when the plugin is deactivated:

The default options are set to use the free version of Thumbshots, so the plugin instantly works on activation without any changes to the default settings. To complete the database integration I have also added a function to get the default options from the database when the plugin is loaded (this function is run from the constructor):

Note: The functions listed here are used as part of the object defined in my previous post.

Now that I have a very simple working plugin it’s time for a little clean up.

Before I start adding addition functions and build additional features in messy procedural style it makes sense at this state to make it object orientated. WordPress continues to support PHP 4.3 and upwards, hence the plugin should also support PHP 4 configurations.

Here is the class made from the original function, variables have been moved to the object’s global scope, the hooks are included in the constructor and the Render() function now contains the regex replacements:

This is much tidier than before

Now to make everything work all that is required is an instance of the object:

As I have an account with Thumbshots.com I thought it would be nice to include it on my blog and have preview images of links in posts. Despite the 1000′s of WordPress plugins available, unfortunately none of them worked specifically for Thumbshots.

I noticed there were a few similar plugins which worked with alternative thumbnail sites, so initially thought that I could hack them up a bit to use with Thumbshots. Another dead end, none of them seamed to have the features I was looking for.

So it looks like I’ll have to make a plugin…

In the whole 24 hours I have been using this version of WordPress I have been impressed with how it has evolved since I last used it, especially in that it is so easy to use. Plugin development is no exception to this.

There are 2 versions of Thumbshots, both a free and paid version (on .org and .com respectively), so it makes sense that if I am to eventually get this plugin to a point where I can publish it that it should support both. The free one can also be used ‘out of the box’ without an account or any configuration, whereas the paid one obviously requires an account and additional settings.

To get the plugin to work I needed to create the plugin information which is simply stuck in a comment block and WordPress recognises it, it looks something like this:

Secondly I needed a short function to perform the core functionality of the plugin. To enable the user to choose when they want to see a preview it made sense to use bbcode style tags so it could be easily used when adding or editing a post. Any URL wrapped in [preview] tags would be converted to a link with thumbnail image. I’ve hard coded the settings for now for testing purposes, the end result is this function:

Finally to get this to work a hook is required which tells WordPress to run my new function on the post content:

That’s it, all done, this is what it produces:

http://www.philbayfield.com

http://www.google.co.uk

http://www.pimpedentertainment.com

To do:

• Add default values
• Store default values in the database
• Modify the function to retrieve the settings from the database
• Add a page in the admin console to customise the settings
• Convert the plugin to OO format