gem-hunter

Note

Repoze.BFG is now known as Pyramid.

Starting Django Project and Application

We will start a project called intranet with a Django application called wiki:

$ django-admin.py startproject intranet
$ cd intranet
intranet $ python manage.py startapp wiki

Now we need to modify our settings.py to include this new application and configure our database connections:

#!/usr/bin/env python
# settings.py

import os
ROOTDIR = os.path.dirname(os.path.realpath(__file__))

# No relational database...
DATABASE_ENGINE = 'sqlite3'
DATABASE_NAME = ':memory:'

# append the following lines:
ZODB = {
    'default': ['file://' + os.path.join(ROOTDIR, 'wiki_db.fs')],
}

# ... other Django configurations ...

MIDDLEWARE_CLASSES = (
    # ... other middlewares ...

    # If everything is ok (aka no exception raised) this middleware will
    # run a transaction.commit() on response.
    'django_zodb.middleware.TransactionMiddleware',
)

INSTALLED_APPS = (
    'django_zodb',  # enable manage.py zshell command
    'wiki',
)

Let's create our model classes. We will need a "root" object that will store our objects (let's name it Wiki) and a model to store the wiki pages itself (Page):

#!/usr/bin/env python
# wiki/models.py

import markdown  # http://pypi.python.org/pypi/Markdown
from django_zodb import models

# models.RootContainer - Define a 'root' object for database. This class
#                        defines __parent__ = __name__ = None
class Wiki(models.RootContainer):
    def pages(self):
        for pagename in sorted(self):
            yield self[pagename]

    def get_absolute_url(self):
        return "/wiki"

    # It's possible to change models.RootContainer settings using Meta
    # configurations. Here we will explicitly define the default values
    class Meta:
        database = 'default'  # Optional. Default: 'default'
        rootname = 'wiki'     # Optional. Default: RootClass.__name__.lower()

# models.Container - We will use Container to add support to subpages.
class Page(models.Model):
    def __init__(self, content="Empty Page."):
        super(Page, self).__init__()
        self.content = content

    def html(self):
        md = markdown.Markdown(safe_mode="escape",
                extensions=('codehilite', 'def_list', 'fenced_code'))
        return md.convert(self.content)

    @property
    def name(self):
        return self.__name__

    def get_absolute_url(self):
        return u"/".join((self.__parent__.get_absolute_url(), self.name))

We've a configured application and models. It's time to map an URL to our view function:

#!/usr/bin/env python
# urls.py

# ... Django default URL configurations ...

urlpatterns = patterns('',
    # ... other URL mappings ...
    (r'^(?P<path>.*)/?$', 'wiki.views.page'),
)

And wiki/views.py:

#!/usr/bin/env python
# views.py

import re

from django.shortcuts import render_to_response
from django.http import HttpResponseRedirect
from django import forms

import transaction
from django_zodb import views
from django_zodb import models

from samples.wiki.models import Wiki, Page

wikiwords = re.compile(ur"\b([A-Z]\w+([A-Z]+\w+)+)")


class PageEditForm(forms.Form):
    content = forms.CharField(widget=forms.Textarea)


class WikiView(views.View):
    def __index__(self, request, context, root, subpath, traversed):
        return HttpResponseRedirect("FrontPage")

    def add(self, request, context, root, subpath, traversed):
        try:
            name = subpath[0]
        except IndexError:
            return HttpResponseRedirect("/")

        if request.method == "POST":
            form = PageEditForm(request.POST)
            if form.is_valid():
                page = Page(form.cleaned_data['content'])
                root[name] = page
                return HttpResponseRedirect(page.get_absolute_url())
        else:
            form = PageEditForm()

        page_data = {
            'name': name,
            'cancel_link': "javascript:history.go(-1)",
            'form': form,
        }
        return render_to_response("edit.html", page_data)
views.registry.register(model=Wiki, view=WikiView())


class PageView(views.View):
    def __index__(self, request, context, root, subpath, traversed):
        content = context.html()

        def check(match):
            word = match.group(1)
            if word in root:
                page = root[word]
                view_url = page.get_absolute_url()
                return '<a href="%s">%s</a>' % (view_url, word)
            else:
                add_url = models.model_path(root, "", "add", word)
                return '<a href="%s">%s</a>' % (add_url, word)

        content = wikiwords.sub(check, content)

        page_data = {
            'context': context,
            'content': content,
            'edit_link': context.get_absolute_url() + "/edit",
            'root': root,
        }
        return render_to_response("page.html", page_data)

    def edit(self, request, context, root, subpath, traversed):
        context_path = models.model_path(context)

        if request.method == "POST":
            form = PageEditForm(request.POST)
            if form.is_valid():
                context.content = form.cleaned_data['content']
                return HttpResponseRedirect(context_path)
        else:
            form = PageEditForm(initial={'content': context.content})

        page_data = {
            'name': context.name,
            'context': context,
            'cancel_link': context_path,
            'form': form,
        }
        return render_to_response("edit.html", page_data)
views.registry.register(model=Page, view=PageView())


def create_frontpage(root):
    frontpage = Page()
    root["FrontPage"] = frontpage
    return root

def page(request, path):
    root = models.get_root(Wiki, setup=create_frontpage)
    return views.get_response_or_404(request, root=root, path=path)

def handle_page_objects(request, result):
    # result is a TraverseResult object.
    # result.context is a Page object found by traverse
    return render_to_response(...)

# Register handle_page_objects function to handle Page objects:
views.registry.register(model=Page, view=handle_page_objects)

class PageView(views.View):
    # This is the 'default' handle (no method_name)
    def __index__(self, request, context, root, subpath, traversed):
        # ... context is a Page object ...
        return render_to_response(...)

    # called when method_name == "edit"
    def edit(self, request, context, root, subpath, traversed):
        # ... context is a Page object ...
        return render_to_response(...)

# Register a PageView *instance* to handle Page objects
views.registry.register(model=Page, view=PageView())

scheme://username:password@host:port/path?arg1=foo&arg2=bar#fraction

mem
mem:
mem://
mem?database_name=memory

file:///tmp/Data.fs
file:///tmp/main.db?database_name=file

file://subdir/Data.fs

zconfig:///my/app/zodb_config.zcml
zconfig:///my/app/zodb_config.zcml#main

mysql://user:password@host:3306?compress=true#mysql_db_name
mysql:///tmp/mysql.sock#local_database
mysql://localhost#database

postgresql://user:password@host:5432#mysql_db_name