Procedimiento completo websockets

Suscribirse a un usuario

Al abrir cualquier ficha del estudiante se suscribe a él (Angular - student/controllers/student.js):

      // Subscribe to student's socket room
      console.log("connecting to socket");
      io.socket.post('/stu/subscribe', {
        action: 'subscribe',
        attributes:{
          id_stu: $scope.studentUser.id 
        }, 
        token: $window.sessionStorage.token 
      }, 
      function(res) {
        console.log("Connected to student: " + res.msg);
      });

La petición se recibe en el servidor (Sails - StudentController.js):

      // Subscribe to websockets events
      //
      subscribe: function(req, res) {
        var action = req.param('action');
        var attributes = req.param('attributes');

        var roomName = 'studentRoom' + attributes.id_stu;

        sails.log.debug("Inside /stu/subscribe. Action: " + action);

        if (req.isSocket) {
            sails.log.debug("Inside /stu/subscribe - isSocket");
            sails.sockets.join(req.socket, roomName);
            res.json({
                msg: "Subscribed to student " + roomName
            });
        }
      },

---

Cancelar suscripción a todos los usuarios

Al abrir el listado de alumnos se cancela la suscripción a todos los alumnos (Angular - supervisor/controllers/students.js):

    // Unsubscribe to student's socket room
    io.socket.post('/stu/unsubscribe', {
      action: 'unsubscribe'
    }, 
    function(res) {
      console.log("Disconnected socket: " + res.msg);
    });

La petición se recibe en el servidor (Sails - StudentController.js):

      // Unsubscribe to websockets events
      //
      unsubscribe: function(req, res) {
        var action = req.param('action');
        //var attributes = req.param('attributes');

        sails.log.debug("Inside /stu/unsubscribe. Action: " + action);

        if (req.isSocket) {
            sails.log.debug("Inside /stu/unsubscribe - isSocket");

            var rooms = sails.sockets.socketRooms(req.socket);
            console.log("Subscribed rooms in socket: " + JSON.stringify(rooms));

            // Leave all rooms
            for(var i=0; i<rooms.length; i++){
                sails.sockets.leave(req.socket, rooms[i]);
                sails.log.debug("Unsusbscribe from room " + room[i]);
            }

            res.json({
                msg: "Unsubscribed from all rooms"
            });
        }
      },

---

Enviar acción sobre el vocabulario a todos los suscritos a un usuario.

Lanzar un mensaje de broadcast a todos los suscritos. Un ejemplo de eliminar un picto (Angular - student/controllers/collections.js):

       // websocket emit vocabulary delete action
        io.socket.post('/stu/vocabulary', {
          action: 'delete',
          attributes: {
            id_stu: $scope.studentUser.id,    
            picto: data
          }
        }, 
        function(res) {
          console.log("Vocabulary emited: " + JSON.stringify(res.msg));
        });

De forma similar al ejemplo anterior con acción delete se hacen las acciones add y update sobre el vocabulario (/stu/vocabulary) o sobre los ensayos (/stu/action) y la configuración del estudiante (/stu/config).

Más info: Acciones en sesiones de trabajo

La petición se recibe en el servidor que genera un mensaje de broadcast a todos los suscritos (Sails - StudentController.js):

          // Logs a vocabulary action and broadcast to anyone subscribed to this student
      vocabulary: function(req, res) {
        var action = req.param('action');
        var attributes = req.param('attributes');

        var roomName = 'studentRoom' + attributes.id_stu;

        sails.log.debug("Inside vocabulary");

        if (req.isSocket) {
            sails.log.debug("Inside vocabulary - isSocket");

            // Send to all sockets subscribed to this room except the own socket that sends the message
            // Parameters: room, action, data to send, socket to avoid sending (the socket that send this)
            sails.sockets.broadcast(roomName, 'vocabulary', { "action": action, "attributes": attributes }, req.socket);

            res.json({
                msg: "Vocabulary "+ action +" action from student " + attributes.id_stu
            });
        }
      },

---

Gestionar las acciones lanzadas

Escucha de dichos mensajes desde el cliente (Angular - student/controllers/collections.js):

// websockets events handling
  io.socket.on('vocabulary', function(data) {
      console.log('Vocabulary '+ data.action +' event received with the following data:');
      console.log(JSON.stringify(data.attributes));

      //$scope.pictos.push(data.attributes.picto.picto);

      switch(data.action){
        case 'add':
          console.log("add action!!!!!!!!!!!!!");
          $scope.reload_pictos();
          break;
        case 'update':
          console.log("update action!!!!!!!!!!!!!");
          $scope.reload_pictos();
          break;
        case 'delete':
          console.log("delete action!!!!!!!!!!!!");
          $scope.reload_pictos();
          break;
      }

      // Socket.io does not live inside the angular lifecycle, and thus Angular
      // doesn't know new data has come in. Inside the socket.io callback,
      // as the last action, added $scope.apply() that lets angular know
      // what data has updated, and refresh what needs to be refreshed.
      $scope.$apply();
  });

Referencias

1. Implementación del servidor Sais.js
2. Implementación del cliente (Android)