Are there any good tutorials for using sitemesh in a grails application?
I'm a pretty experienced Grails developer, but most of my experience has been with using grails for serving up JSON/XML to a flex app and some relatively simple HTML websites.
I've been diving deeper into using the sitemesh integration in grails and I'm struggling a little to find best practices for some more complex configurations, and I'm curious if there are any good tutorials or examples out there. The original Sitemesh website isn't that useful as the tags it talks about aren't directly exposed in grails.
A google search is mostly showing old mailing list posts and some vanilla sitemesh stuff which is helping me to move a little further along, but it's a lot of trial and error.
I fully understand how the basic g:layoutTitle, g:layoutHead, and g:layoutBody tags work. Those are easy and well documented.
The kinds of things that I'd like to see examples for:
g:applyLayout - the documentation on this is weak and I don't fully understand the uses suggested in the main docs. How is this different than setting the
meta name='layout' content='foo'property?g:pageProperty - some better examples on how to pull and use properties into the main template by setting the values as meta tags in the page that's being decorated. The grails docs on pageProperty show only the onload attribute from the body being brought forward. I think you can also use meta tag values here as well, anything else?
can you use multiple levels of sitemesh layouts? My testing seems to make me think that I can't, but that seems to reduce reusability. I think that the answer here is some usage of the g:applyLayout, but that's where I'm struggling the most.
Answer
the g:pageProperty is a very powerful, but very poorly documented thing. Lets say in my layout I specify where to put some content like this:
<html>
<body>
<g:pageProperty name="page.header" />
</body>
Now in my page I can specify some content:
<content tag="header">
<!-- header -->
</content>
Sitemesh will take the content tag, regardless of actual position in the HTML of the page and place it where it needs to go in the flow of the layout.
Even better, if within my page I render a template that also specifies a content area with a tag of "header", it will overwrite the first declaration, and it will be the template's content that will be rendered in the final layout.