z3c.zrtresource 1.1.0

Templated Resources

One of the design goals of Zope is to allow designers to check in HTML template, CSS and Javascript files, which just work (with some additional information). For HTML code we use Zope’s Page Templates to accomplish this objective. For CSS and Javascript we did not need such a feature until now, since those files were largely static or variables could be inserted using other ways at runtime.

However, in CSS URLs – for example for background images – are now frequently inserted into CSS directives. However, the path layout for the designer might not equal the resource file structure. This package provides a simple mechanism to replace strings by another.

To accomplish this, a templated resource is provided. The template syntax is provided in a way that it does not interfere with the syntax of the resource. For both, Javascript and CSS, this is a comment of the form /* ... */.

Here is the general syntax:

<COMMAND-BEGIN> <ZRT-COMMAND>: <COMMAND-ARGUMENTS> <COMMAND-END>

Here is an example for CSS:

/* zrt-replace: ".." "@@" */

To demonstrate this feature, we first have to create a CSS file.

>>> import tempfile
>>> fn = tempfile.mktemp('.css')
>>> open(fn, 'w').write('''\
... /* zrt-replace: "../img1" "++resource++/img" */
... /* zrt-replace: "fontName" "Arial, Tahoma" */
... h1 {
...   color: red;
...   font: fontName;
...   background: url('../img1/mybackground.gif');
... }
...
... h2 {
...   color: red;
...   background: url('../img2/mybackground.gif');
... }
... /* zrt-replace: "../img2" "++resource++/img" */
... ''')

The global replace command replaces a string with another. It is only active in the lines after it was declared. Thus, in this case, the second command is meaningless.

Now we create a ZRT resource from the resource factory …

>>> from z3c.zrtresource import ZRTFileResourceFactory
>>> cssFactory = ZRTFileResourceFactory(fn, None, 'site.css')

>>> from zope.publisher.browser import TestRequest
>>> css = cssFactory(TestRequest())

and render the resource:

>>> print css.GET()
h1 {
  color: red;
  font: Arial, Tahoma;
  background: url('++resource++/img/mybackground.gif');
}
<BLANKLINE>
h2 {
  color: red;
  background: url('../img2/mybackground.gif');
}

As you can see only the first URL was replaced, because of the incorrect position of the second statement.

And that’s all! In your ZCML you can use this factory as follows:

<zrt-resource
    name="site.css"
    path="css/site.css"
    />

zrt-resource Directive

This package provides a new directive to use the special resource directive. Let’s register it first:

>>> from zope.configuration import xmlconfig
>>> context = xmlconfig.string('''
... <configure i18n_domain="zope">
...   <include package="z3c.zrtresource" file="meta.zcml" />
... </configure>
... ''')

Now we can register a resource:

>>> import tempfile
>>> fn = tempfile.mktemp('.css')
>>> open(fn, 'w').write('''\
... /* zrt-replace: "../img1" "++resource++/img" */
... h1 {
...   color: red;
...   background: url('../img1/mybackground.gif');
... }
... ''')

>>> context = xmlconfig.string('''
... <configure xmlns="http://namespaces.zope.org/browser" i18n_domain="zope">
...   <zrt-resource
...       name="test.css"
...       file="%s" />
... </configure>
... ''' %fn, context=context)

Now let’s see whether the adapter has been registered:

>>> import zope.component
>>> import zope.interface
>>> from zope.publisher.browser import TestRequest
>>> resource = zope.component.getAdapter(
...     TestRequest(), zope.interface.Interface, name='test.css')

Now run it:

>>> print resource.GET()
h1 {
  color: red;
  background: url('++resource++/img/mybackground.gif');
}

CHANGES