Implement SSO overriding avatars.

Implemented by having Discourse download the image from the provided URL
and treating it as a custom upload.

Adds two more parameters to the SSO site’s response:

* `avatar_url` specifies the URL of the overriding avatar.
* `avatar_force_update` Discourse does not re-download avatars that
has already been download from the same URL. Setting this to true forces
Discourse to re-download the avatar in `avatar_url`

Note that both parameters are ignored if `sso_overrides_avatar` is set
to false.

app/assets/javascripts/discourse/controllers/preferences.js.es6

@@ -12,6 +12,7 @@ export default ObjectController.extend({
 
   allowAvatarUpload: Discourse.computed.setting('allow_uploaded_avatars'),
   allowUserLocale: Discourse.computed.setting('allow_user_locale'),
+  ssoOverridesAvatar: Discourse.computed.setting('sso_overrides_avatar'),
 
   selectedCategories: function(){
     return [].concat(this.get("watchedCategories"), this.get("trackedCategories"), this.get("mutedCategories"));

app/assets/javascripts/discourse/templates/user/preferences.js.handlebars

@@ -82,9 +82,9 @@
         {{bound-avatar model "large"}}
         {{#if allowAvatarUpload}}
           <button {{action showAvatarSelector}} class="btn pad-left no-text"><i class="fa fa-pencil"></i></button>
-        {{else}}
+        {{else}} {{#unless ssoOverridesAvatar}}
           <a href="//gravatar.com/emails" target="_blank" title="{{i18n user.change_avatar.gravatar_title}}" class="btn no-text"><i class="fa fa-pencil"></i></a>
-        {{/if}}
+        {{/unless}} {{/if}}
       </div>
     </div>
 

app/models/discourse_single_sign_on.rb

@@ -121,9 +121,32 @@ class DiscourseSingleSignOn < SingleSignOn
       user.name = User.suggest_name(name || username || email)
     end
 
+    if SiteSetting.sso_overrides_avatar && (
+      avatar_force_update == "true" ||
+      avatar_force_update.to_i != 0 ||
+      sso_record.external_avatar_url != avatar_url)
+      begin
+        tempfile = FileHelper.download(avatar_url, 1.megabyte, "sso-avatar")
+
+        upload = Upload.create_for(user.id, tempfile, "external-avatar", File.size(tempfile.path), { origin: avatar_url })
+
+        user.uploaded_avatar_id = upload.id
+
+        if !user.user_avatar.contains_upload?(upload.id)
+          user.user_avatar.custom_upload_id = upload.id
+        end
+      rescue SocketError
+        # skip saving, we are not connected to the net
+        Rails.logger.warn "Failed to download external avatar: #{avatar_url}, socket error - user id #{ user.id }"
+      ensure
+        tempfile.close! if tempfile && tempfile.respond_to?(:close!)
+      end
+    end
+
     # change external attributes for sso record
     sso_record.external_username = username
     sso_record.external_email = email
     sso_record.external_name = name
+    sso_record.external_avatar_url = avatar_url
   end
 end

app/models/single_sign_on_record.rb

@@ -6,15 +6,16 @@ end
 #
 # Table name: single_sign_on_records
 #
-#  id                :integer          not null, primary key
-#  user_id           :integer          not null
-#  external_id       :string(255)      not null
-#  last_payload      :text             not null
-#  created_at        :datetime
-#  updated_at        :datetime
-#  external_username :string(255)
-#  external_email    :string(255)
-#  external_name     :string(255)
+#  id                    :integer          not null, primary key
+#  user_id               :integer          not null
+#  external_id           :string(255)      not null
+#  last_payload          :text             not null
+#  created_at            :datetime
+#  updated_at            :datetime
+#  external_username     :string(255)
+#  external_email        :string(255)
+#  external_name         :string(255)
+#  external_avatar_url   :string(255)
 #
 # Indexes
 #

config/locales/server.en.yml

@@ -769,6 +769,7 @@ en:
     sso_overrides_email: "Overrides local email with external site email from SSO payload (WARNING: discrepancies can occur due to normalization of local emails)"
     sso_overrides_username: "Overrides local username with external site username from SSO payload (WARNING: discrepancies can occur due to differences in username length/requirements)"
     sso_overrides_name: "Overrides local name with external site name from SSO payload (WARNING: discrepancies can occur due to normalization of local names)"
+    sso_overrides_avatar: "Overrides user avatar with external site avatar from SSO payload. If enabled, disabling allow_uploaded_avatars is highly recommended"
 
     enable_local_logins: "Enable local username and password login based accounts. (Note: this must be enabled for invites to work)"
     allow_new_registrations: "Allow new user registrations. Uncheck this to prevent anyone from creating a new account."

config/site_settings.yml

@@ -229,6 +229,9 @@ login:
   sso_overrides_email: false
   sso_overrides_username: false
   sso_overrides_name: false
+  sso_overrides_avatar:
+    default: false
+    client: true
 
 
 users:

db/migrate/20140817011612_add_external_avatar_url_to_single_sign_on_record.rb

@@ -0,0 +1,5 @@
+class AddExternalAvatarUrlToSingleSignOnRecord < ActiveRecord::Migration
+  def change
+    add_column :single_sign_on_records, :external_avatar_url, :string
+  end
+end

lib/single_sign_on.rb

@@ -1,5 +1,5 @@
 class SingleSignOn
-  ACCESSORS = [:nonce, :name, :username, :email,
+  ACCESSORS = [:nonce, :name, :username, :email, :avatar_url, :avatar_force_update,
                :about_me, :external_id]
   FIXNUMS = []
   NONCE_EXPIRY_TIME = 10.minutes