Blog of Jeff A blog about programming and random other things.

In part 1 and part 2, we installed Django and installed. Now we really begin (well, the configuring part at least).

 

Settings

Depending on the purpose of your website, you need to configure different settings to make django aware of these differences such as features you want enabled, debugging mode, timezone, etc. Luckily, there are usually very little in terms of configuration.

Open settings.py for editing. The variable names and comments in this file makes most of the settings self-explanatory, so I'll briefly explain the settings we're going to edit.

 

• DATABASE_ENGINE As stated earlier, I inted on using SQLite, so I put 'sqlite3' here. Enter your own database engine and other database information preceding it.
• TIME_ZONE I don't know about you, but I don't happen to live in Chicago. You'll have to see the list of various time zone choices. I've entered America/New Yorkfor this, but you'll have to change this when deploy django to the server's timezone.
• TEMPLATE_DIRS contains a list/array/tuple of strings that specify the directories that Django should look in for template files. It should be in absolute path, but if you prefer to enter the relative paths, type in the following code on the top of thesettings.py file:

import os
rel = lambda *x: os.path.join(os.path.abspath(os.path.dirname(__filename__)), *x)

TEMPLATE_DIRS = (
     rel('templates'),
)

• INSTALLED_APPS contains a list of applications that this project utilizes. Applications range from vvarious features such as user authentication to your website.

We're also planning to take advantage of Django's automatic administrative interface. So add the bolded code to your INSTALLED_APPS.

INSTALLED_APPS = (
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.sites',
    'django.contrib.admin',
)

While we're at it, we can name our application we're about to create. I'm simply going ot name the application chat. To add it to your INSTALLED_APPS variable, put the project name period and the application name. My folder name is dchat and the application name as chat. So my INSTALLED_APPS should finally look like this:

INSTALLED_APPS = (
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.sites',
    'django.contrib.admin',
    'dchat.chat',
)

Save and close your configuration file. Now back to the terminal/command line. We want to create the application using this:

python manage.py startapp chat

Which will generate a few things for us (yay).

URLs

Next thing we're going to touch upon are urls. Urls are associated by regular expressions to view code. In Django, URLs are considered an important part of your website as your content. Memorizable and readable URLs assist end users in their navigation.

In urls.py, uncomment all the comments that refer to the django automatic admin interface so your urls.py should look something like this:

from django.conf.urls.defaults import *
from django.contrib import admin
admin.autodiscover()

urlpatterns = patterns('',
    (r'^admin/(.*)', admin.site.root),
)

The url patterns variable stores the way django should dispatch incoming urls. Django will automatically strip out the domain information (eg - mydomain.com) and compares the resource location with this list of regular expressions in order until it finds a match.

Each line in the patterns function call is a tuple that first contains the regular expression to match. If that expression matches, it is tied to a particular view function to call. In the case with the one above, any urls that are prefixed with admin/ are directed to admin.site.root (or the automatic admin interface). The r in front of the regular expression strip makes the string "raw", mean you cannot escape any characters. This is particularly useful for regular expressions so you don't have to escape all your slashes.

In addition to the project urls.py, you each application can have it's own urls.py. We're simply going to make a reference that tells that all urls that match none of the above patterns (aka, the automatic admin url pattern), we'll redirect it to our chat application. So add the line below the admin regular expression link:

(r'^', include('dchat.chat.urls')),

This will match any other urls in this application and redirect it to the chat/urls.py url pattern list. The advantage of doing this is to make our chat application more modularized. So we can change the base path of the chat app here, and the chat app will still function exactly the same.

Of course if you tried to view the index page (or admin url for that matter), you'd probably get something like this:

We simply create url.py in the chat subfolder that is identical to the url.py for the project and if we reload the page, we get a Page not found. This won't be a problem in the next tutorial, where we start adding functionality to our chat

 

To be continued...