Added user roles and enabled plugins to settings ETag

Otherwise the cache of /api/settings would not be properly invalidated
on a change in either the user login state or the set of active plugins.

See also #1576

src/octoprint/server/api/settings.py

@@ -8,6 +8,7 @@ __copyright__ = "Copyright (C) 2014 The OctoPrint Project - Released under terms
 import logging
 
 from flask import request, jsonify, make_response
+from flask.ext.login import current_user
 from werkzeug.exceptions import BadRequest
 
 from octoprint.events import eventManager, Events
@@ -30,11 +31,18 @@ def _etag(lm=None):
 		lm = _lastmodified()
 
 	connection_options = printer.__class__.get_connection_options()
+	plugins = sorted(octoprint.plugin.plugin_manager().enabled_plugins)
+	if current_user is not None and not current_user.is_anonymous():
+		roles = sorted(current_user.roles)
+	else:
+		roles = []
 
 	import hashlib
 	hash = hashlib.sha1()
 	hash.update(str(lm))
 	hash.update(repr(connection_options))
+	hash.update(repr(plugins))
+	hash.update(repr(roles))
 	return hash.hexdigest()
 
 @api.route("/settings", methods=["GET"])

src/octoprint/users.py

@@ -464,6 +464,10 @@ class User(UserMixin):
 
 		return self._get_setting(path)
 
+	@property
+	def roles(self):
+		return list(self._roles)
+
 	def set_setting(self, key, value):
 		if not isinstance(key, (tuple, list)):
 			path = [key]