Add a configurable avatar system and add an internal avatar system for enterprise

avatars/avatars.py

@@ -0,0 +1,63 @@
+import hashlib
+
+class Avatar(object):
+  def __init__(self, app=None):
+    self.app = app
+    self.state = self._init_app(app)
+
+  def _init_app(self, app):
+    return AVATAR_CLASSES[app.config.get('AVATAR_KIND', 'Gravatar')](
+      app.config['SERVER_HOSTNAME'],
+      app.config['PREFERRED_URL_SCHEME'])
+
+  def __getattr__(self, name):
+    return getattr(self.state, name, None)
+
+
+class BaseAvatar(object):
+  """ Base class for all avatar implementations. """
+  def __init__(self, server_hostname, preferred_url_scheme):
+    self.server_hostname = server_hostname
+    self.preferred_url_scheme = preferred_url_scheme
+
+  def get_url(self, email, size=16, name=None):
+    """ Returns the full URL for viewing the avatar of the given email address, with
+        an optional size.
+    """
+    raise NotImplementedError
+
+  def compute_hash(self, email, name=None):
+    """ Computes the avatar hash for the given email address. If the name is given and a default
+        avatar is being computed, the name can be used in place of the email address. """
+    raise NotImplementedError
+
+
+class GravatarAvatar(BaseAvatar):
+  """ Avatar system that uses gravatar for generating avatars. """
+  def compute_hash(self, email, name=None):
+    return hashlib.md5(email.strip().lower()).hexdigest()
+
+  def get_url(self, email, size=16, name=None):
+    computed = self.compute_hash(email, name=name)
+    return '%s://www.gravatar.com/avatar/%s?d=identicon&size=%s' % (self.preferred_url_scheme,
+                                                                    computed, size)
+
+class LocalAvatar(BaseAvatar):
+  """ Avatar system that uses the local system for generating avatars. """
+  def compute_hash(self, email, name=None):
+    if not name and not email:
+      return ''
+
+    prefix = name if name else email
+    return prefix[0] + hashlib.md5(email.strip().lower()).hexdigest()
+
+  def get_url(self, email, size=16, name=None):
+    computed = self.compute_hash(email, name=name)
+    return '%s://%s/avatar/%s?size=%s' % (self.preferred_url_scheme, self.server_hostname,
+                                          computed, size)
+
+
+AVATAR_CLASSES = {
+  'gravatar': GravatarAvatar,
+  'local': LocalAvatar
+}