So, Webmin has a very powerful module system, that allows you to package code for easy distribution and installation. A Webmin module is simply a directory with some files in it. Only one file is mandatory to make the directory into a “module”: module.info
So, we create a directory named extjs within the Webmin directory (/usr/libexec/webmin on my system), and make a file called module.info with the following contents:
name=ExtJS desc=ExtJS AJAX Toolkit depends=1.360 version=0.1 hidden=1
Here I’ve given it a name, and a short description, noted the version of Webmin it depends on, given it a version (I’m going to stat it at 0.1, though the contained ExtJS version is 2.0b), and set it to be hidden. The hidden option means that users won’t be able to see this module in the UI, but other modules can make calls to it. Later, if I decide to add configurable options to this library that I do want users to be able to see, I can make it visible and add an icon and a UI.
Now, I can start dropping in my files. I merely unzipped the ExtJS bundle, deleted the extraneous files, and dropped it into an ext directory within the module directory. That’s just to make it easy to update ExtJS components separately from the helper functions that I write in Perl in the top-level directory.
So, the simplest thing to automate away is the inclusion of the script tags that load the library. So, I’ll create a header_text function in a file called extjs-lib.pl (Webmin has a convention of calling function libraries modulename-lib.pl), which looks like this:
Here we pull in the Webmin core library, pull in the configuration for this module (which I’ll cover in a couple of days when I’ve completed the configuration code for this module), and build the function to return the bits of text we need to properly load ExtJS and its stylesheets.
Believe it or not, we’ve now got a library that can be used by other Webmin modules or by themes. Webmin has a foreign_require function that will pull libraries like this in under their own namespace. So, when I need to use ExtJS, I can do this:
foreign_require("extjs", "extjs-lib.pl"); print extjs::header_text();
All done! In a few days I’ll be finished with the first full-featured version of this library, and will wrap it up for distribution, along with some proof-of-concept modules that show how to use a full-featured AJAX interface without breaking text-mode browsers and readers, among other things.