Weather App Tutorial. Part 1 of 5. Preparation

It is Blog Action Day tomorrow so I decided to participate in it as a blogger again. The theme for this year is "Climate Change". After a little brainstorm, I came up with an idea to write a tutorial how to build an app which regularly checks local weather and lets you compare different weather features for months of different years.

I'll use Yahoo! Weather to check the current weather. From all information that it provides, we'll be mostly interested in temperature, humidity, wind speed, and visibility in the current location. The app will check the weather regularly, will allow you to show the current weather, and also provide a graph comparing average monthly weathers throughout years.

So let's start with the new project. I have quite a clean computer and want to do the app the nice way. So first of all, I will install virtualenv to be able to install third-party python libraries in a closed environment which will only be used for this project (I have already installed setuptools and django).

# install virtualenv
sudo easy_install virtualenv

I created a directory Projects in my home directory and cd to it.

Let's create a virtual environment and start the new project and app.

# create virtual environment "climate_change_env"
virtualenv climate_change_env
cd climate_change_env/
# activate the environment
source bin/activate

Since now I see (climate_change_env) as a prefix to each command line. I'll type deactivate at some point later to get out of this virtual environment.

# create django project "blog_action_day_2009"
django-admin.py startproject blog_action_day_2009
cd blog_action_day_2009/
# create django app "climate_change"
django-admin.py startapp climate_change
# create folders for templates and media
mkdir templates media

To get started quickly, I will use sqlite3 database now. As I am using python 2.5, I don't need to install sqlite3 module, because it's already there. So I open the settings.py and define those settings:

import os
PROJECT_DIR = os.path.dirname(__file__)
# ...
DATABASE_ENGINE = "sqlite3"
DATABASE_NAME = "blog_action_day_2009.sqlite3"
# ...
MEDIA_ROOT = os.path.join(PROJECT_DIR, "media")
MEDIA_URL = "/media/"
ADMIN_MEDIA_PREFIX = "/admin/media/"
# ...
TEMPLATE_DIRS = [
    os.path.join(PROJECT_DIR, "templates"),
    ]
# ...
INSTALLED_APPS = (
    "django.contrib.auth",
    "django.contrib.contenttypes",
    "django.contrib.sessions",
    "django.contrib.sites",
    "django.contrib.admin",
    "climate_change",
    )

Now we'll need those parts:

• Models for locations and imported weather information.
• Management command for importing data from Yahoo! Weather.
• Template tag for displaying latest weather.
• View for displaying a graph.

But I'll continue about that tomorrow.

To end today's post, let's watch a video about a regular guy who talks about weather when he has nothing to say: