Get a fully-qualified URL for the current Django site

You need to generate a fully-qualified URL to a Django page, in particular outside of a web request context (in which you would have access to server variables), such as an automated process that generates e-mail with links.  You may be able to generate a root-relative URL from a reverse lookup; there’s also get_absolute_url() of course, but it’s provided on a per-model basis, and in any case shouldn’t be coupled with URL elements such as protocol and host name.  You can get the domain part of the host name from the current site object, but Django currently (as of version 1.0.2) provides no means for reliably generating a fully-qualified URL (including protocol and port) outside of a web request context.  In the function current_site_url(), below, I have used two custom settings, MY_SITE_PROTOCOL and MY_SITE_PORT.  (My current practice is to prefix custom settings with MY_,  place them in a parallel module in the project called my_settings.py, and import the custom settings into the project settings module.)

def current_site_url():
    """Returns fully qualified URL (no trailing slash) for the current site."""
    from django.contrib.sites.models import Site
    current_site = Site.objects.get_current()
    protocol = getattr(settings, 'MY_SITE_PROTOCOL', 'http')
    port     = getattr(settings, 'MY_SITE_PORT', '')
    url = '%s://%s' % (protocol, current_site.domain)
    if port:
        url += ':%s' % port
    return url

Now, I still don’t really have enough information to construct a fully-qualified URL for the most general case, because in taking advantage of the django.root setting, my code no longer “knows” what Django’s root path is.  That was good for decoupling the URLconf from the web server conf, but again, I need to generate fully-qualified URLs outside of a web request context, so I don’t have access the django.root setting.  My solution has been to add another custom setting, MY_DJANGO_URL_PATH, which corresponds to the django.root setting (a comment Django’s mod_python handler module indicates that the handler must be called before importing any settings in order for os.environ to be set up correctly with respect to settings).  With that, I can get my Django root URL with this function:

def django_root_url(fq=False):
    """Returns base URL (no trailing slash) for the current project.

    Setting fq parameter to a true value will prepend the base URL
    of the current site to create a fully qualified URL.

    The name django_root_url is used in favor of alternatives
    (such as project_url) because it corresponds to the mod_python
    PythonOption django.root setting used in Apache.
    """
    url = getattr(settings, 'MY_DJANGO_URL_PATH', '')
    if fq:
        url = current_site_url() + url
    return url

With these functions and Django’s reverse URL lookup, I can construct fully-qualified URLs.

django.root decouples URLconf from Apache conf

Maybe I didn’t read the detailed change log for Django 1.0 … in any case I missed this important new feature. If you are using Apache and mod_python to serve your Django site, you can add a directive to your Apache conf that will tell Django the root path of your Django URLs:

PythonOption django.root /apps

It seemed as though most Django examples assumed that your Django site was served from the root URL of the web server — even though that wasn’t a requirement in any way. The problem before this setting was available is that it coupled your Django project root URLconf to your web server configuration because Django always received the full URL path. Now with this setting, the root Django path from your Apache config is stripped off before matching url patterns in your Django URLconfs.

Thanks, Django!