Template reuse¶

Important

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It’s wasteful, and generally harmful, to have the same code repeated in multiple places, even if that code is HTML. A single definition means that only that definition need ever be changed, and you can’t wind up with two definitions that are subtly different. There are two ways of avoiding this: fragment views and macros.

Fragment Views¶

Fragment views are the preferred method. When working with content classes, you may want to render a content class in a view for another class. The HTML you would want to include is usually the default view’s HTML, stripped of its leading and trailing HTML, like <html>, <head> and body.

So given a default view named +index , you would create a new view called +fragment, and move the body of the HTML into it. The +index TAL would then include context/@@+fragment to copy the content in.

You could then reuse +fragment in other locations where you want to display that content object.

The +fragment view can also be viewed in a browser by hand-hacking its URL. Since it’s only meant to be included in other pages, allowing a browser to view it is not really pure. Providing it this way permits AJAX to reuse it, and normal users would need to hand-hack URLs to even be aware of it.)

Macros¶

In cases where you’re not dealing with a particular content object, it may make more sense to use a macro. For example, if you’re writing a page that seems to have certain things repeated frequently, you can define a macro for the repeated code, then use the macro later in the page.

Single-view Macros¶

To refer to the macro mymacro within the page where you defined it, you can use template/macros/mymacro. template refers to the template that is currently being rendered.

Context-wide Macros¶

If you have macros that need to be reused across pages for a given content object, then you may wish to create a view that holds the relevant macros for that content object, like +macros .

You can then refer to it as context/@@/+macros/mymacro. It is rarely a good idea for one view to refer to the macro of a “normal” view, because that reuse will not be obvious to the casual observer.

Multi-context Macros¶

If you wish to reuse macros for views across various context objects, you’ll need to create a reference to the correct Zope Page Template. You can do this by making a member of the view class which is an instance of ViewPageTemplateFile.

The view class would look like:

class FooView(LaunchpadView):
    bar_macros = ViewPageTemplateFile("../templates/bar-macros.pt")

A reference to the macro mymacro would look like:

view/bar_macros/macros/mymacro