Adds a class that can detect whether a user has uploaded a custom avatar

app/models/user.rb

@@ -300,14 +300,15 @@ class User < ActiveRecord::Base
     template.gsub("{size}", "45")
   end
 
-  def avatar_template
-    if SiteSetting.allow_uploaded_avatars? && use_uploaded_avatar
   # the avatars might take a while to generate
   # so return the url of the original image in the meantime
+  def uploaded_avatar_path
+    return unless SiteSetting.allow_uploaded_avatars? && use_uploaded_avatar
     uploaded_avatar_template.present? ? uploaded_avatar_template : uploaded_avatar.try(:url)
-    else
-      User.gravatar_template(email)
   end
+
+  def avatar_template
+    uploaded_avatar_path || User.gravatar_template(email)
   end
 
   # Updates the denormalized view counts for all users

lib/avatar_detector.rb

@@ -0,0 +1,32 @@
+require_dependency 'user'
+require 'net/http'
+
+class AvatarDetector
+
+  def initialize(user)
+    raise "Tried to detect an avatar on a non-user instance" unless user && user.is_a?(User)
+
+    @user = user
+  end
+
+  def has_custom_avatar?
+    return true if @user.uploaded_avatar_path
+    has_custom_gravatar?
+  end
+
+  # Check whether the user has a gravatar by performing a HTTP HEAD request to
+  # Gravatar using the `d=404` parameter.
+  def has_custom_gravatar?
+    result = Net::HTTP.start('www.gravatar.com') do |http|
+      http.open_timeout = 2
+      http.read_timeout = 2
+      http.head("/avatar/#{User.email_hash(@user.email)}?d=404")
+    end
+
+    return result.code.to_i == 200
+  rescue
+    # If the HTTP request fails, assume no gravatar
+    false
+  end
+
+end

spec/components/avatar_detector_spec.rb

@@ -0,0 +1,67 @@
+# encoding: utf-8
+require 'spec_helper'
+require_dependency 'avatar_detector'
+
+describe AvatarDetector do
+
+  describe "construction" do
+
+    it "raises an error without a user" do
+      -> { AvatarDetector.new(nil) }.should raise_error
+    end
+
+    it "raises an error on a non-user object" do
+      -> { AvatarDetector.new(Array.new) }.should raise_error
+    end
+
+  end
+
+  describe "has_custom_avatar?" do
+
+    describe "with a user" do
+      let(:user) { User.new(use_uploaded_avatar: true) }
+      let(:avatar_detector) { AvatarDetector.new(user) }
+
+      describe "when the user doesn't have an uploaded_avatar_path" do
+
+        before do
+          user.stubs(:uploaded_avatar_path)
+        end
+
+        it "returns true if they have a custom gravatar" do
+          avatar_detector.expects(:has_custom_gravatar?).returns(true)
+          avatar_detector.has_custom_avatar?.should be_true
+        end
+
+        it "returns false if they don't have a custom gravatar" do
+          avatar_detector.expects(:has_custom_gravatar?).returns(false)
+          avatar_detector.has_custom_avatar?.should be_false
+        end
+      end
+
+
+      context "when the user doesn't have an uploaded_avatar_path" do
+        let(:user) { User.new(use_uploaded_avatar: true) }
+        let(:avatar_detector) { AvatarDetector.new(user) }
+
+        describe "when the user has an uploaded avatar" do
+          before do
+            user.expects(:uploaded_avatar_path).returns("/some/uploaded/file.png")
+          end
+
+          it "returns true" do
+            avatar_detector.has_custom_avatar?.should be_true
+          end
+
+          it "doesn't call has_custom_gravatar" do
+            avatar_detector.expects(:has_custom_gravatar?).never
+            avatar_detector.has_custom_avatar?
+          end
+
+        end
+      end
+
+    end
+  end
+
+end