gistfile1.py

from copy import copy
from hashlib import md5
from urllib import urlencode
from django import template
from django.conf import settings

register = template.Library()

class GravatarNode(template.Node):
    def __init__(self, user, size=None):
        self.user = template.Variable(user)
        self.size = size
    
    def render(self, context):
        GRAVATAR_URL = getattr(settings, 'GRAVATAR_URL',
            'http://www.gravatar.com/avatar/')
        
        # For available options, see this URL: http://en.gravatar.com/site/implement/url
        GRAVATAR_OPTIONS = copy(getattr(settings, 'GRAVATAR_OPTIONS', {}))
        
        if self.size is not None:
            GRAVATAR_OPTIONS['s'] = self.size
        
        user = self.user.resolve(context)
        email = user.email or 'INVALID_EMAIL'
        return u'%s%s?%s' % (
            GRAVATAR_URL,
            md5(email).hexdigest(),
            urlencode(GRAVATAR_OPTIONS),
        )

@register.tag
def gravatar(parser, token):
    bits = token.split_contents()
    if len(bits) == 2:
        kwargs = {
            'user': bits[1]
        }
    elif len(bits) == 3:
        kwargs = {
            'user': bits[1],
            'size': bits[2]
        }
    else:
        raise template.TemplateSyntaxError, "%r tag requires either one or two argument(s)." % token.contents.split()[0]
    
    return GravatarNode(**kwargs)