grails tag library needs to include javascript

Question

I am trying to write a grails plugin to allow grails apps to scan qr codes. I'm using jsqrcode https://github.com/LazarSoft/jsqrcode to perform the actual interpretation of the qr codes.

This means that I need to include a number of javascript files in any page that uses my qrcode scanning tag.

Right now, I've created a tag that just imports the scripts and looks like:

StringBuilder sb = new StringBuilder()
sb << """<script src="/${grails.util.Metadata.current.'app.name'}/js/jsqrcode/grid.js"></script>"""
...
sb.toString()

This feels klugey to me.

Is there a better (right?) way to go about this?

To clarify, creating a tag to import specific javascript feels like a kludge for at least two reasons. First this requires that the person using the plugin must include this 'import' tag exactly once in any page using this library (I'm not a fan of unobvious dependency). And second, I'm concerned that the use of

${grails.util.Metadata.current.'app.name'}

could cause problems for people that use url mappings.

Answer 1

For dealing with JS includes it would be best to tie into the Grails Asset Pipeline plugin which is becoming a default plugin in grails 2.4 That plugin already has ways of making sure files are only included once, check out the documentation.