basic WebSocket handler

eventman_server.py

@@ -29,6 +29,7 @@ import tornado.ioloop
 import tornado.options
 from tornado.options import define, options
 import tornado.web
+import tornado.websocket
 from tornado import gen, escape, process
 
 import utils
@@ -88,6 +89,9 @@ class RootHandler(BaseHandler):
             self.write(fd.read())
 
 
+# Keep track of WebSocket connections.
+_ws_clients = []
+
 class CollectionHandler(BaseHandler):
     """Base class for handlers that need to interact with the database backend.
     
@@ -243,6 +247,23 @@ class CollectionHandler(BaseHandler):
                 continue
             out, err = yield gen.Task(self.run_subprocess, [script], stdin_data, env)
 
+    def build_ws_url(self, path, proto='ws', host=None):
+        """Return a WebSocket url from a path."""
+        return '%s://%s/ws/%s' % (proto, host or self.request.host, path)
+
+    @gen.coroutine
+    def send_ws_message(self, url, message):
+        """Send a WebSocket message to all the connected clients.
+
+        :param url: WebSocket url
+        :type url: str
+        :param message: message to send
+        :type message: str
+        """
+        ws = yield tornado.websocket.websocket_connect(url)
+        ws.write_message(message)
+        ws.close()
+
 
 class PersonsHandler(CollectionHandler):
     """Handle requests for Persons."""
@@ -345,9 +366,11 @@ class EventsHandler(CollectionHandler):
             'merged': merged
         }
         self.run_triggers('update_person_in_event', stdin_data=stdin_data, env=env)
-        if old_person_data and old_person_data.get('attended') != new_person_data.get('attended') \
-                and new_person_data.get('attended'):
-            self.run_triggers('attends', stdin_data=stdin_data, env=env)
+        if old_person_data and old_person_data.get('attended') != new_person_data.get('attended'):
+            ws_url = self.build_ws_url(path='event/%s/updates' % id_)
+            self.send_ws_message(ws_url, json.dumps(doc.get('persons') or []))
+            if new_person_data.get('attended'):
+                self.run_triggers('attends', stdin_data=stdin_data, env=env)
         return {'event': doc}
 
     def handle_delete_persons(self, id_, person_id):
@@ -445,6 +468,30 @@ class SettingsHandler(BaseHandler):
         self.write({'settings': settings})
 
 
+class WebSocketEventUpdatesHandler(tornado.websocket.WebSocketHandler):
+    def open(self, event_id, *args, **kwds):
+        logging.debug('WebSocketEventUpdatesHandler.on_open event_id:%s' % event_id)
+        _ws_clients.append(self)
+        logging.debug('WebSocketEventUpdatesHandler.on_open %s clients connected' % len(_ws_clients))
+
+    def on_message(self, message):
+        logging.debug('WebSocketEventUpdatesHandler.on_message')
+        count = 0
+        for client in _ws_clients:
+            if client == self:
+                continue
+            client.write_message(message)
+            count += 1
+        logging.debug('WebSocketEventUpdatesHandler.on_message sent message to %d clients' % count)
+
+    def on_close(self):
+        logging.debug('WebSocketEventUpdatesHandler.on_close')
+        try:
+            _ws_clients.remove(self)
+        except Exception, e:
+            logging.warn('WebSocketEventUpdatesHandler.on_close error closing websocket: %s', str(e))
+
+
 def run():
     """Run the Tornado web application."""
     # command line arguments; can also be written in a configuration file,
@@ -475,6 +522,7 @@ def run():
             (r"/(?:index.html)?", RootHandler, init_params),
             (r"/ebcsvpersons", EbCSVImportPersonsHandler, init_params),
             (r"/settings", SettingsHandler, init_params),
+            (r"/ws/+event/+(?P<event_id>\w+)/+updates/?", WebSocketEventUpdatesHandler),
             (r'/(.*)', tornado.web.StaticFileHandler, {"path": "angular_app"})
         ],
         template_path=os.path.join(os.path.dirname(__file__), "templates"),

static/js/angular-websocket.js

@@ -0,0 +1,382 @@
+(function() {
+  'use strict';
+
+  var noop = angular.noop;
+  var objectFreeze  = (Object.freeze) ? Object.freeze : noop;
+  var objectDefineProperty = Object.defineProperty;
+  var isString   = angular.isString;
+  var isFunction = angular.isFunction;
+  var isDefined  = angular.isDefined;
+  var isObject   = angular.isObject;
+  var isArray    = angular.isArray;
+  var forEach    = angular.forEach;
+  var arraySlice = Array.prototype.slice;
+  // ie8 wat
+  if (!Array.prototype.indexOf) {
+    Array.prototype.indexOf = function(elt /*, from*/) {
+      var len = this.length >>> 0;
+      var from = Number(arguments[1]) || 0;
+      from = (from < 0) ? Math.ceil(from) : Math.floor(from);
+      if (from < 0) {
+        from += len;
+      }
+
+      for (; from < len; from++) {
+        if (from in this && this[from] === elt) { return from; }
+      }
+      return -1;
+    };
+  }
+
+  // $WebSocketProvider.$inject = ['$rootScope', '$q', '$timeout', '$websocketBackend'];
+  function $WebSocketProvider($rootScope, $q, $timeout, $websocketBackend) {
+
+    function $WebSocket(url, protocols, options) {
+      if (!options && isObject(protocols) && !isArray(protocols)) {
+        options = protocols;
+        protocols = undefined;
+      }
+
+      this.protocols = protocols;
+      this.url = url || 'Missing URL';
+      this.ssl = /(wss)/i.test(this.url);
+
+      // this.binaryType = '';
+      // this.extensions = '';
+      // this.bufferedAmount = 0;
+      // this.trasnmitting = false;
+      // this.buffer = [];
+
+      // TODO: refactor options to use isDefined
+      this.scope                       = options && options.scope                      || $rootScope;
+      this.rootScopeFailover           = options && options.rootScopeFailover          && true;
+      this.useApplyAsync               = options && options.useApplyAsync              || false;
+      this.initialTimeout              = options && options.initialTimeout             || 500; // 500ms
+      this.maxTimeout                  = options && options.maxTimeout                 || 5 * 60 * 1000; // 5 minutes
+      this.reconnectIfNotNormalClose   = options && options.reconnectIfNotNormalClose  || false;
+
+      this._reconnectAttempts = 0;
+      this.sendQueue          = [];
+      this.onOpenCallbacks    = [];
+      this.onMessageCallbacks = [];
+      this.onErrorCallbacks   = [];
+      this.onCloseCallbacks   = [];
+
+      objectFreeze(this._readyStateConstants);
+
+      if (url) {
+        this._connect();
+      } else {
+        this._setInternalState(0);
+      }
+
+    }
+
+
+    $WebSocket.prototype._readyStateConstants = {
+      'CONNECTING': 0,
+      'OPEN': 1,
+      'CLOSING': 2,
+      'CLOSED': 3,
+      'RECONNECT_ABORTED': 4
+    };
+
+    $WebSocket.prototype._normalCloseCode = 1000;
+
+    $WebSocket.prototype._reconnectableStatusCodes = [
+      4000
+    ];
+
+    $WebSocket.prototype.safeDigest = function safeDigest(autoApply) {
+      if (autoApply && !this.scope.$$phase) {
+        this.scope.$digest();
+      }
+    };
+
+    $WebSocket.prototype.bindToScope = function bindToScope(scope) {
+      var self = this;
+      if (scope) {
+        this.scope = scope;
+        if (this.rootScopeFailover) {
+          this.scope.$on('$destroy', function() {
+            self.scope = $rootScope;
+          });
+        }
+      }
+      return self;
+    };
+
+    $WebSocket.prototype._connect = function _connect(force) {
+      if (force || !this.socket || this.socket.readyState !== this._readyStateConstants.OPEN) {
+        this.socket = $websocketBackend.create(this.url, this.protocols);
+        this.socket.onmessage = angular.bind(this, this._onMessageHandler);
+        this.socket.onopen  = angular.bind(this, this._onOpenHandler);
+        this.socket.onerror = angular.bind(this, this._onErrorHandler);
+        this.socket.onclose = angular.bind(this, this._onCloseHandler);
+      }
+    };
+
+    $WebSocket.prototype.fireQueue = function fireQueue() {
+      while (this.sendQueue.length && this.socket.readyState === this._readyStateConstants.OPEN) {
+        var data = this.sendQueue.shift();
+
+        this.socket.send(
+          isString(data.message) ? data.message : JSON.stringify(data.message)
+        );
+        data.deferred.resolve();
+      }
+    };
+
+    $WebSocket.prototype.notifyOpenCallbacks = function notifyOpenCallbacks(event) {
+      for (var i = 0; i < this.onOpenCallbacks.length; i++) {
+        this.onOpenCallbacks[i].call(this, event);
+      }
+    };
+
+    $WebSocket.prototype.notifyCloseCallbacks = function notifyCloseCallbacks(event) {
+      for (var i = 0; i < this.onCloseCallbacks.length; i++) {
+        this.onCloseCallbacks[i].call(this, event);
+      }
+    };
+
+    $WebSocket.prototype.notifyErrorCallbacks = function notifyErrorCallbacks(event) {
+      for (var i = 0; i < this.onErrorCallbacks.length; i++) {
+        this.onErrorCallbacks[i].call(this, event);
+      }
+    };
+
+    $WebSocket.prototype.onOpen = function onOpen(cb) {
+      this.onOpenCallbacks.push(cb);
+      return this;
+    };
+
+    $WebSocket.prototype.onClose = function onClose(cb) {
+      this.onCloseCallbacks.push(cb);
+      return this;
+    };
+
+    $WebSocket.prototype.onError = function onError(cb) {
+      this.onErrorCallbacks.push(cb);
+      return this;
+    };
+
+
+    $WebSocket.prototype.onMessage = function onMessage(callback, options) {
+      if (!isFunction(callback)) {
+        throw new Error('Callback must be a function');
+      }
+
+      if (options && isDefined(options.filter) && !isString(options.filter) && !(options.filter instanceof RegExp)) {
+        throw new Error('Pattern must be a string or regular expression');
+      }
+
+      this.onMessageCallbacks.push({
+        fn: callback,
+        pattern: options ? options.filter : undefined,
+        autoApply: options ? options.autoApply : true
+      });
+      return this;
+    };
+
+    $WebSocket.prototype._onOpenHandler = function _onOpenHandler(event) {
+      this._reconnectAttempts = 0;
+      this.notifyOpenCallbacks(event);
+      this.fireQueue();
+    };
+
+    $WebSocket.prototype._onCloseHandler = function _onCloseHandler(event) {
+      this.notifyCloseCallbacks(event);
+      if ((this.reconnectIfNotNormalClose && event.code !== this._normalCloseCode) || this._reconnectableStatusCodes.indexOf(event.code) > -1) {
+        this.reconnect();
+      }
+    };
+
+    $WebSocket.prototype._onErrorHandler = function _onErrorHandler(event) {
+      this.notifyErrorCallbacks(event);
+    };
+
+    $WebSocket.prototype._onMessageHandler = function _onMessageHandler(message) {
+      var pattern;
+      var self = this;
+      var currentCallback;
+      for (var i = 0; i < self.onMessageCallbacks.length; i++) {
+        currentCallback = self.onMessageCallbacks[i];
+        pattern = currentCallback.pattern;
+        if (pattern) {
+          if (isString(pattern) && message.data === pattern) {
+            applyAsyncOrDigest(currentCallback.fn, currentCallback.autoApply, message);
+          }
+          else if (pattern instanceof RegExp && pattern.exec(message.data)) {
+            applyAsyncOrDigest(currentCallback.fn, currentCallback.autoApply, message);
+          }
+        }
+        else {
+          applyAsyncOrDigest(currentCallback.fn, currentCallback.autoApply, message);
+        }
+      }
+
+      function applyAsyncOrDigest(callback, autoApply, args) {
+        args = arraySlice.call(arguments, 2);
+        if (self.useApplyAsync) {
+          self.scope.$applyAsync(function() {
+            callback.apply(self, args);
+          });
+        } else {
+          callback.apply(self, args);
+          self.safeDigest(autoApply);
+        }
+      }
+
+    };
+
+    $WebSocket.prototype.close = function close(force) {
+      if (force || !this.socket.bufferedAmount) {
+        this.socket.close();
+      }
+      return this;
+    };
+
+    $WebSocket.prototype.send = function send(data) {
+      var deferred = $q.defer();
+      var self = this;
+      var promise = cancelableify(deferred.promise);
+
+      if (self.readyState === self._readyStateConstants.RECONNECT_ABORTED) {
+        deferred.reject('Socket connection has been closed');
+      }
+      else {
+        self.sendQueue.push({
+          message: data,
+          deferred: deferred
+        });
+        self.fireQueue();
+      }
+
+      // Credit goes to @btford
+      function cancelableify(promise) {
+        promise.cancel = cancel;
+        var then = promise.then;
+        promise.then = function() {
+          var newPromise = then.apply(this, arguments);
+          return cancelableify(newPromise);
+        };
+        return promise;
+      }
+
+      function cancel(reason) {
+        self.sendQueue.splice(self.sendQueue.indexOf(data), 1);
+        deferred.reject(reason);
+        return self;
+      }
+
+      if ($websocketBackend.isMocked && $websocketBackend.isMocked() &&
+              $websocketBackend.isConnected(this.url)) {
+        this._onMessageHandler($websocketBackend.mockSend());
+      }
+
+      return promise;
+    };
+
+    $WebSocket.prototype.reconnect = function reconnect() {
+      this.close();
+
+      var backoffDelay = this._getBackoffDelay(++this._reconnectAttempts);
+
+      var backoffDelaySeconds = backoffDelay / 1000;
+      console.log('Reconnecting in ' + backoffDelaySeconds + ' seconds');
+
+      $timeout(angular.bind(this, this._connect), backoffDelay);
+
+      return this;
+    };
+    // Exponential Backoff Formula by Prof. Douglas Thain
+    // http://dthain.blogspot.co.uk/2009/02/exponential-backoff-in-distributed.html
+    $WebSocket.prototype._getBackoffDelay = function _getBackoffDelay(attempt) {
+      var R = Math.random() + 1;
+      var T = this.initialTimeout;
+      var F = 2;
+      var N = attempt;
+      var M = this.maxTimeout;
+
+      return Math.floor(Math.min(R * T * Math.pow(F, N), M));
+    };
+
+    $WebSocket.prototype._setInternalState = function _setInternalState(state) {
+      if (Math.floor(state) !== state || state < 0 || state > 4) {
+        throw new Error('state must be an integer between 0 and 4, got: ' + state);
+      }
+
+      // ie8 wat
+      if (!objectDefineProperty) {
+        this.readyState = state || this.socket.readyState;
+      }
+      this._internalConnectionState = state;
+
+
+      forEach(this.sendQueue, function(pending) {
+        pending.deferred.reject('Message cancelled due to closed socket connection');
+      });
+    };
+
+    // Read only .readyState
+    if (objectDefineProperty) {
+      objectDefineProperty($WebSocket.prototype, 'readyState', {
+        get: function() {
+          return this._internalConnectionState || this.socket.readyState;
+        },
+        set: function() {
+          throw new Error('The readyState property is read-only');
+        }
+      });
+    }
+
+    return function(url, protocols) {
+      return new $WebSocket(url, protocols);
+    };
+  }
+
+  // $WebSocketBackendProvider.$inject = ['$window', '$log'];
+  function $WebSocketBackendProvider($window, $log) {
+    this.create = function create(url, protocols) {
+      var match = /wss?:\/\//.exec(url);
+      var Socket, ws;
+      if (!match) {
+        throw new Error('Invalid url provided');
+      }
+
+      // CommonJS
+      if (typeof exports === 'object' && require) {
+        try {
+          ws = require('ws');
+          Socket = (ws.Client || ws.client || ws);
+        } catch(e) {}
+      }
+
+      // Browser
+      Socket = Socket || $window.WebSocket || $window.MozWebSocket;
+
+      if (protocols) {
+        return new Socket(url, protocols);
+      }
+
+      return new Socket(url);
+    };
+    this.createWebSocketBackend = function createWebSocketBackend(url, protocols) {
+      $log.warn('Deprecated: Please use .create(url, protocols)');
+      return this.create(url, protocols);
+    };
+  }
+
+  angular.module('ngWebSocket', [])
+  .factory('$websocket', ['$rootScope', '$q', '$timeout', '$websocketBackend', $WebSocketProvider])
+  .factory('WebSocket',  ['$rootScope', '$q', '$timeout', 'WebsocketBackend',  $WebSocketProvider])
+  .service('$websocketBackend', ['$window', '$log', $WebSocketBackendProvider])
+  .service('WebSocketBackend',  ['$window', '$log', $WebSocketBackendProvider]);
+
+
+  angular.module('angular-websocket', ['ngWebSocket']);
+
+  if (typeof module === 'object' && typeof define !== 'function') {
+    module.exports = angular.module('ngWebSocket');
+  }
+}());