Switch avatars to be built out of CSS and only overlayed with the gravatar when a non-default exists

avatars/avatars.py

@@ -1,4 +1,5 @@
 import hashlib
+import math
 
 class Avatar(object):
   def __init__(self, app=None):
@@ -7,8 +8,7 @@ class Avatar(object):
 
   def _init_app(self, app):
     return AVATAR_CLASSES[app.config.get('AVATAR_KIND', 'Gravatar')](
-      app.config['SERVER_HOSTNAME'],
-      app.config['PREFERRED_URL_SCHEME'])
+      app.config['PREFERRED_URL_SCHEME'], app.config['AVATAR_COLORS'], app.config['HTTPCLIENT'])
 
   def __getattr__(self, name):
     return getattr(self.state, name, None)
@@ -16,48 +16,83 @@ class Avatar(object):
 
 class BaseAvatar(object):
   """ Base class for all avatar implementations. """
-  def __init__(self, server_hostname, preferred_url_scheme):
-    self.server_hostname = server_hostname
+  def __init__(self, preferred_url_scheme, colors, http_client):
     self.preferred_url_scheme = preferred_url_scheme
+    self.colors = colors
+    self.http_client = http_client
 
-  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.
+  def get_mail_html(self, name, email_or_id, size=16, kind='user'):
+    """ Returns the full HTML and CSS for viewing the avatar of the given name and email address,
+        with an optional size.
     """
-    raise NotImplementedError
+    data = self.get_data(name, email_or_id, kind)
+    url = self._get_url(data['hash'], size) if kind != 'team' else None
+    font_size = size - 6
 
-  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
+    if url is not None:
+      # Try to load the gravatar. If we get a non-404 response, then we use it in place of
+      # the CSS avatar.
+      response = self.http_client.get(url)
+      if response.status_code == 200:
+        return """<img src="%s" width="%s" height="%s" alt="%s"
+                       style="vertical-align: middle;">""" % (url, size, size, kind)
+
+    radius = '50%' if kind == 'team' else '0%'
+    letter = '&Omega;' if kind == 'team' and data['name'] == 'owners' else data['name'].upper()[0]
+
+    return """
+      <span style="width: %spx; height: %spx; background-color: %s; font-size: %spx;
+                   line-height: %spx; margin-left: 2px; margin-right: 2px; display: inline-block;
+                   vertical-align: middle; text-align: center; color: white; border-radius: %s">
+        %s
+      </span>
+""" % (size, size, data['color'], font_size, size, radius, letter)
+
+  def get_data_for_user(self, user):
+    return self.get_data(user.username, user.email, 'robot' if user.robot else 'user')
+
+  def get_data_for_team(self, team):
+    return self.get_data(team.name, team.name, 'team')
+
+  def get_data_for_org(self, org):
+    return self.get_data(org.username, org.email, 'org')
+
+  def get_data(self, name, email_or_id, kind='user'):
+    """ Computes and returns the full data block for the avatar:
+        {
+          'name': name,
+          'hash': The gravatar hash, if any.
+          'color': The color for the avatar
+        }
+    """
+    colors = self.colors
+    hash_value = hashlib.md5(email_or_id.strip().lower()).hexdigest()
+
+    byte_count = int(math.ceil(math.log(len(colors), 16)))
+    byte_data = hash_value[0:byte_count]
+    hash_color = colors[int(byte_data, 16) % len(colors)]
+
+    return {
+      'name': name,
+      'hash': hash_value,
+      'color': hash_color,
+      'kind': kind
+    }
+
+  def _get_url(self, hash_value, size):
+    """ Returns the URL for displaying the overlay avatar. """
+    return None
 
 
 class GravatarAvatar(BaseAvatar):
   """ Avatar system that uses gravatar for generating avatars. """
-  def compute_hash(self, email, name=None):
-    email = email or ""
-    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)
+  def _get_url(self, hash_value, size=16):
+    return '%s://www.gravatar.com/avatar/%s?d=404&size=%s' % (self.preferred_url_scheme,
+                                                              hash_value, size)
 
 class LocalAvatar(BaseAvatar):
   """ Avatar system that uses the local system for generating avatars. """
-  def compute_hash(self, email, name=None):
-    email = email or ""
-    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)
-
+  pass
 
 AVATAR_CLASSES = {
   'gravatar': GravatarAvatar,