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############################################################################
# Example of registering rendering adapters for object types so that
# the page doesn't have to know anything about about the objects, only
# that it wants to render some particular view of the object.
############################################################################
import random
from zope.interface import implements, Interface
from twisted.python.components import registerAdapter, Adapter
from nevow import inevow
from nevow import loaders
from nevow import rend
from nevow import tags as T
############################################################################
# Define some simple classes for out application data.
class Person:
def __init__(self, firstName, lastName, email):
self.firstName = firstName
self.lastName = lastName
self.email = email
class Bookmark:
def __init__(self, name, url):
self.name = name
self.url = url
############################################################################
# Create interfaces for the different views of application objects.
# These are nothing but marker interfaces to register a rendering adapt
# for simplicity sake you can consider them to be named views.
class ISummaryView(Interface):
"""Render a summary of an object.
"""
class IFullView(Interface):
"""Full view of the object.
"""
############################################################################
# Define the rendering adapters that do the real work of rendering an
# object.
class PersonSummaryView(Adapter):
"""Render a summary of a Person.
"""
implements(inevow.IRenderer, ISummaryView)
def rend(self, data):
return T.div(_class="summaryView person")[
T.a(href=['mailto:',self.original.email])[
self.original.firstName, ' ', self.original.lastName
]
]
class PersonFullView(Adapter):
"""Render a full view of a Person.
"""
implements(inevow.IRenderer, IFullView)
def rend(self, data):
attrs = ['firstName', 'lastName', 'email']
return T.div(_class="fullView person")[
T.p['Person'],
T.dl[
[(T.dt[attr], T.dd[getattr(self.original, attr)])
for attr in attrs]
]
]
class BookmarkSummaryView(Adapter):
"""Render a summary of a Person.
"""
implements(inevow.IRenderer, ISummaryView)
def rend(self, data):
return T.div(_class="summaryView bookmark")[
T.a(href=self.original.url)[self.original.name]
]
class BookmarkFullView(Adapter):
"""Render a full view of a Bookmark.
"""
implements(inevow.IRenderer, IFullView)
def rend(self, data):
attrs = ['name', 'url']
return T.div(_class="fullView bookmark")[
T.p['Bookmark'],
T.dl[
[(T.dt[attr], T.dd[getattr(self.original, attr)])
for attr in attrs]
]
]
############################################################################
# Register the rendering adapters. Note, these could easily be defined in
# a text file and registered by name rather than class object.
registerAdapter(PersonSummaryView, Person, ISummaryView)
registerAdapter(PersonFullView, Person, IFullView)
registerAdapter(BookmarkSummaryView, Bookmark, ISummaryView)
registerAdapter(BookmarkFullView, Bookmark, IFullView)
############################################################################
# Create some data for the application to do something with.
objs = [
Person('Matt', 'Goodall', 'matt@pollenation.net'),
Bookmark('Nevow', 'http://www.nevow.com'),
Person('Somebody', 'Else', 'somebody@else.net'),
Bookmark('Twisted', 'http://twistedmatrix.com/'),
Bookmark('Python', 'http://www.python.org'),
]
############################################################################
# Page that simply renders a summary of the objects and chooses one at
# random to display a full view of.
class Page(rend.Page):
addSlash = True
def render_one(self, ctx, data):
return IFullView(random.choice(objs))
docFactory = loaders.stan(
T.html[
T.body[
T.ul(data=objs, render=rend.sequence)[
T.li(pattern='item')[lambda c,d: ISummaryView(d)]
],
T.hr,
render_one,
],
]
)
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