Child Pages

There are various methods to construct a page hierarchy which depends on the structure of the application and the complexity.

The simplest way is using the child_ specials

class ChildPage(rend.Page):
    addSlash = True

    docFactory = loaders.stan(tags.html[
        tags.body[
            "This is a child page"
        ]
    ])

class APage(rend.Page):
    addSlash = True

    child_aChild = ChildPage()

    docFactory = loaders.stan(tags.html[
        tags.head[
            tags.title["Child Example"]
        ],
        tags.body[
            tags.a(href="/aChild/")["Go to child page"]
        ]
    ])

This constructs a page with a child called ChildPage? accessed via /aChild/.

This example can be extended further to demonstrate overriding the childFactory method

class ComplexChildren(rend.Page):
    addSlash = True
    docFactory = loaders.stan(tags.html[
        tags.body[
            "Another child"
        ]
    ])

class ChildPage(rend.Page):
    addSlash = True

    docFactory = loaders.stan(tags.html[
        tags.body[
            "A page"
        ]
    ])

    def childFactory(self, ctx, childSegment):
        if childSegment == "myChild":
            return ComplexChildren()
        else:
            rend.Page.childFactory(self, ctx, childSegment)

This provides a convenient way to locate multiple children which might require different initialisation arguments. Note that childSegment is a string containing the resource that was requested.

As an example if we wanted to allocate the same resource to a bunch of child resources, we can create a dictionary with references to the page resource and instantiate it with the child segment.

class ChildPage(rend.Page):
    myChildren = {
        'Dog': Animal,
        'Cat': Animal,
        'Zebra': Animal
    }

    def childFactory(self, ctx, childSegment):
        if childSegment in self.myChildren:
            return self.myChildren[childSegment](childSegment)
        else:
            rend.Page.childFactory(self, ctx, childSegment)

This is also a convenient way to provide REST style arguments.