Using Templates

Stan is a great tool however it should be used sparingly to maintain proper separation of logic and presentation.

Nevow uses XML templates with the Nevow XML namespace. An example of such a template would be 

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en" xmlns:n="http://nevow.com/ns/nevow/0.1">
    <head>
        <title>Hello World Page</title>
    </head>
    <body>
        <div n:render="myContent"/>
    </body>
</html>

Using this template with a page is done simply as follows 

class APage(rend.Page):
    addSlash = True

    docFactory = loaders.xmlfile('template.xml')

    def render_myContent(self, ctx, data):
        return ctx.tag[ tags.div(id="hello", _class="helloicator")["Hello World"]]

Page Fragments

A common query is why one can't use multiple templates to render a header and footer for example. This is entirely possible but the method is not intuitive coming from other common frameworks or languages.

We start with a standard page and create render methods for returning our fragment instance. 

class AFragment(rend.Fragment):
    docFactory = loaders.xmlfile('fragment.xml', ignoreDocType=True)

    def render_fragmentContent(self, ctx, data):
        return ctx.tag["Pretend this is some dynamic content"]

class APage(rend.Page):
    addSlash = True

    docFactory = loaders.xmlfile('template.xml')

    def render_myContent(self, ctx, data):
        return ctx.tag[ tags.div(id="hello", _class="helloicator")["Hello World"]]

    def render_myFragment(self, ctx, data):
        frag = AFragment()
        return ctx.tag[frag]

Our template.xml then looks as follows 

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en" xmlns:n="http://nevow.com/ns/nevow/0.1">
    <head>
        <title>Hello World Page</title>
    </head>
    <body>
        <div n:render="myContent"/>
        <div n:render="myFragment"/>
    </body>
</html>

Our fragment.xml simply looks like this 

<?xml version="1.0" encoding="iso-8859-1"?>
<div xmlns:n="http://nevow.com/ns/nevow/0.1" n:render="fragmentContent"></div>
jethro@divmod.org