How to customize LXQT for Meilix

We had a task of customizing the LXQT (LXQt is the Qt port and the upcoming version of LXDE, the Lightweight Desktop Environment) desktop environment in Meilix for events. For example, we can use a distro at events for presentations so during presentations things like system sounds, notifications and panel can be disturbing elements of presentations so we required LXQT to be pre configured for that so the time required in configuration is not wasted or none of the presentations are disturbed.

The default configuration of LXQT are present in ~/.config/lxqt. Configuration files are in This directory is initialized automatically. The default configuration for new users is found in /etc/xdg/lxqt but we are going to use skel for this so that if there are some changes in future in the LXQT code and they do not match default settings we can always be back to default settings by deleting user side changes. Similar to LXDE. LXQt provides a GUI applications to change its settings as well.

While Openbox is the default window manager we have used in Meilix with  LXQt, you can specify a different window manager to use with LXQt via by editing ~/.config/lxqt/session.conf. To a window manager of choice. Change the following line:



We have used the Openbox for Meilix.

To create a configuration for panel we can go to ~/.config/lxqt and edit the panel.conf file if it is not present we can create a file named panel.conf and add/edit the code.



GIF representing auto hide of panel.

In order to configure more things like notification we can edit the ~/.config/lxqt/notification.conf.

We can change things like the placement or the size of notification or the timeout of notification in this file.

For eg:



We can now place all the configurations inside the skel folder so that every new user gets the same configurations we have made.


Snackbar for Error Handling in Twitter Followers Insight loklak App

In this blog post am going to explain how the Twitter Followers Insight app handles error which occurs when when no query is passed to the “Search” function i.e., when the search is proceeded with an empty query.

How to handle the Exception

In such cases, I have used SNACKBAR / TOAST. Snackbar / Toast is used to popup an error notification on the screen when an exception occurs.

Script for Snackbar / Toast:

In the below script, initially the error is set to null i.e., no error. The “showError” function is which is being called when there occurs a situation of no query or an empty query. The function below helps to show an error popup which only shows till a time limit.

    $scope.error = null;

    $scope.showError = function() {
        setTimeout(function(){ $(".snackbar").removeClass("show") }, 3000);


In this script, it checks whether the query passed is undefined or empty. If yes, then the error message which was null earlier is changed and that error is showed up on the screen to the end user. Snackbars animate upwards from the edge of the screen.

        if ($scope.query === '' || $scope.query === undefined) {
            $scope.spinner = false;
            $scope.error = "Please enter a valid Username";



Implementing Notifications in Open Event Server

In FOSSASIA’s Open Event Server project, along with emails, almost all actions have necessary user notifications as well. So, when a new session is created or a session is accepted by the event organisers, along with the email, a user notification is also sent. Though showing the user notification is mainly implemented in the frontend site but the content to be shown and on which action to show is strictly decided by the server project.

A notification essentially helps an user to get the necessary information while staying in the platform itself and not needing to go to check his/her email for every action he performs. So unlike email which acts as a backup for the informations, notification is more of an instant thing.


The Notifications API is mostly like all other JSON API endpoints in the open event project. However in Notifications API we do not allow any to send a POST request. The admin of the server is able to send a GET a request to view all the notifications that are there in the system while a user can only view his/her notification. As of PATCH we allow only the user to edit his/her notification to mark it as read or not read. Following is the schema for the API:

class NotificationSchema(Schema):
    API Schema for Notification Model

    class Meta:
        Meta class for Notification API schema
        type_ = 'notification'
        self_view = 'v1.notification_detail'
        self_view_kwargs = {'id': '<id>'}
        self_view_many = 'v1.microlocation_list_post'
        inflect = dasherize

    id = fields.Str(dump_only=True)
    title = fields.Str(allow_none=True, dump_only=True)
    message = fields.Str(allow_none=True, dump_only=True)
    received_at = fields.DateTime(dump_only=True)
    accept = fields.Str(allow_none=True, dump_only=True)
    is_read = fields.Boolean()
    user = Relationship(attribute='user',
                        self_view_kwargs={'id': '<id>'},
                        related_view_kwargs={'notification_id': '<id>'},

The main things that are shown in the notification from the frontend are the
title and message. The title is the text that is shown without expanding the entire notification that gives an overview about the message in case you don’t want to read the entire message. The message however provides the entire detail that is associated with the action performed. The user relationship stores which user the particular notification is related with. It is a one-to-one relationship where one notification can only belong to one user. However one user can have multiple notifications. Another important attribute is the is_read attribute. This is the only attribute that is allowed to be changed. By default, when we make an entry in the database, is_read is set to FALSE. Once an user has read the notification, a request is sent from the frontend to change is_read to TRUE.

The different actions for which we send notification are stored in the models/ file as global variables.

USER_CHANGE_EMAIL = "User email"'
NEW_SESSION = 'New Session Proposal'
PASSWORD_CHANGE = 'Change Password'
EVENT_ROLE = 'Event Role Invitation'
TICKET_PURCHASED = 'Ticket(s) Purchased'
TICKET_PURCHASED_ATTENDEE = 'Ticket(s) purchased to Attendee    '
EVENT_EXPORTED = 'Event Exported'
EVENT_EXPORT_FAIL = 'Event Export Failed'
EVENT_IMPORTED = 'Event Imported'

HTML Templates

The notification title and message that is stored in the database and later served via the Notification API is created using some string formatting HTML templates. We firstly import all the global variables that represent the various actions from the notification model. Then we declare a global dict type variable named NOTIFS which stores all title and messages to be stored in the notification table.

        'title': u'New session proposal for {event_name}',
        'message': u"""The event <strong>{event_name}</strong> has received
             a new session proposal.<br><br>
            <a href='{link}' class='btn btn-info btn-sm'>View Session</a>""",
        'recipient': 'Organizer',

This is an example of the contents stored inside the dict. For every action, there is a dict with attributes
title, message and recipient. Title contains the brief overview of the entire notification whereas message contains a more vivid description with proper links. Recipient contains the one who receives the notification. So for example in the above code snippet, it is a notification for a new session created. The notification goes to the organizer. The title and message contains named placeholders which are later replaced by particular values using python’s .format() function.

Notification Helper

Notification helper module contains two main parts :-

  1. A parent function which saves the notification to the table related to the user to whom the notification belongs.
  2. Individual notification helper functions that are used by the APIs to save notification after various actions are performed.

Parent Function

def send_notification(user, action, title, message):
    if not current_app.config['TESTING']:
        notification = Notification(,
        save_to_db(notification, msg="Notification saved")
        record_activity('notification_event', user=user, action=action, title=title)

() is the parent function which takes as parameters user, action, title and message and stores them in the notification table in the database. The user is the one to whom the notification belongs to, action represents the particular action in an API which triggered the notification. Title and message are the contents that are shown in the frontend in the form of a notification. The frontend can implement it as a dropdown notification like facebook or a desktop notification like gitter or whatsapp. After the notification is saved we also update the activity table with the action that a notification has been saved for a user with the following action and title. Later, the Notification API mentioned in the very beginning of the blog uses this data that is being stored now and serves it as a JSON response.

Individual Functions

Apart from this, we have individual functions that uses the parent function to store notifications particular to a particular actions. For example, we have a send_notif_new_session_organizer() function which is used to save notification for all the organizers of an event that a new session has been added to their particular event. This function is called when a POST request is made in the Sessions API and the data is saved successfully. The function is executed for all the organizers of the event for which the session has been created.

def send_notif_new_session_organizer(user, event_name, link):
    message_settings = MessageSettings.query.filter_by(action=NEW_SESSION).first()
    if not message_settings or message_settings.notification_status == 1:
        notif = NOTIFS[NEW_SESSION]
        action = NEW_SESSION
        title = notif['title'].format(event_name=event_name)
        message = notif['message'].format(event_name=event_name, link=link)

        send_notification(user, action, title, message)

In the above function, we take in 3 parameters, user, event_name and link. The value of the user parameter is used to link the notification to that particular user. Event_name and link are used in the title and message of the notification that is saved in the database. Firstly in the function we check if there is certain message setting which tells that the user doesn’t want to receive notifications related to new sessions being created. If not, we proceed. We get the title and message strings from the NOTIFS dict from the file.

After that, using string formatting we get the actual message. For example,

u'New session proposal for {event_name}'.format(‘FOSSASIA’)

would give us a resulting string of the form:

u'New session proposal for FOSSASIA'

After this, we use this variables and send them as parameters to the send_notification() parent function to save the notification properly.



Displaying Proper Notification While Image is Being Uploaded in Phimpme

In this blog, I will explain how to display App Icon and appropriate text messages in the notification bar while the image is being uploaded on the various social media platform in Phimpme Android application.

Displaying Application icon in the Notification Bar

Whenever Phimpme application uses the notification the application icon should be present during the progress bar is showing and after the image has been uploaded to the social network website.

In the notification bar there are two types of the icon that can be set:

  • Small icon
  • Large Icon

In the small icon, we are putting the upload sign to tell the users that the image is being uploaded.

In the large icon, I am putting the logo of the Phimpme application. This way when the user exits the application while there is an upload process going on, he or she will know that the upload process is from the Phimpme application.

To set the app icon in the Notification bar:


To set the small icon in the Notification bar:


Displaying appropriate account name while uploading the Image

While uploading an Image the notification bar should show the appropriate Account Name in which the account is being uploaded. For example, if the image is being uploaded on Google Plus then the Notification should display “Uploading the image on Google Plus”.

For this, we need to modify the NotificationHandler.make() function and make it accept String resource as a parameter. We can then modify setContentTitle() function to display the appropriate message.

public static void make(@StringRes int title){

//Display Notification code over here


setContentTitle() function in Phimpme to display the appropriate function:

mBuilder.setContentTitle(ActivitySwitchHelper.getContext().getString(R.string.upload_progress) + " " + ActivitySwitchHelper.getContext().getResources().getString(title))

Notification make() function after the changes:

public static void make(@StringRes int title){
   mNotifyManager = (NotificationManager) ActivitySwitchHelper.getContext().getSystemService(Context.NOTIFICATION_SERVICE);
   mBuilder = new NotificationCompat.Builder(ActivitySwitchHelper.getContext());
   mBuilder.setContentTitle(ActivitySwitchHelper.getContext().getString(R.string.upload_progress) + " " + ActivitySwitchHelper.getContext().getResources().getString(title))
   mBuilder.setProgress(0, 0, true);
   // Issues the notification


Notification makes any application more interactive and show live updates even when the application is in use. By following this method users can be aware of the upload functionality and in which account the image is beign uploaded.




Sending Data between components of SUSI MagicMirror Module

SUSI MagicMirror module is a module to add SUSI assistant right on your MagicMirror. The software for MagicMirror constitutes of an Electron app to which modules can be added easily. Since there are many modules, there might be functionalities that need interaction between various modules by transfer of information. MagicMirror also provides a node_helper script that facilitates a module to perform some background tasks. Therefore, a mechanism to transfer information from node_helper to various components of module is also needed.

MagicMirror provides an inbuilt module notification system that can be used to send notification across the modules and a socket notification system to send information between node_helper and various components of the system.

Our codebase for SUSI MagicMirror is divided mainly into two parts. A Main module that handles all the process of hotword detection, speech recognition, calling SUSI API and saving audio after Text to Speech and a Renderer module which performs the task of managing the display of content on the Mirror Screen and playing back the file obtained by Speech Synthesis. Plainly put, Main module mainly handles the backend logic of the application and the Renderer handles the frontend. Main and Renderer module work on different layers of the application and to facilitate communication between them, we need to make a mechanism. A schematic of flow that is needed to be maintained can be highlighted as:

As you can see in the above diagram, we need to transfer a lot of information between the components. We display animation and text based on the current state of recognition in the  module, thus we need to transfer this information frequently. This task is accomplished by utilizing the inbuilt socket notification system in the MagicMirror. For every event like when system enters into listening , busy or recognized speech state, we need to pass message to renderer. To achieve this, we made a rendererSend function to send notification to renderer.

const rendererSend =  (event: NotificationType , payload: any) => {
   this.sendSocketNotification(event, payload);

This function takes an event and a payload as arguments. Event tells which event occurred and payload is any data that we wish to send. This method in turn calls the method provided by MagicMirror module to send socket notifications within the module.

When certain events occur like when system enters busy state or listening state, we trigger the rendererSend call to send a socket notification to the module. The rendererSend method is supplied in the State Machine Components available to every state. The task of sending notifications can be done using the code snippet as follows:

// system enters busy state
this.components.rendererSend("busy", {});
// send speech recognition hypothesis text to renderer
this.components.rendererSend("recognized", {text: recognizedText});
// send susi api output json to renderer to display interactive results while Speech Output is performed
this.components.rendererSend("speak", {data: susiResponse});

The socket notification sent via the above method is received in SUSI Module via a callback called socketNotificationReceived . We need to define this callback with implementation while registering module to MagicMirror. So, we register the MMM-SUSI-AI module by adding the definition for socketNotificationReceived method.

Module.register("MMM-SUSI-AI", {
//other function definitions
   // define socketNotificationReceived function
   socketNotificationReceived: function (notification, payload) {
       susiMirror.receivedNotification(notification, payload);

In this way, we send all the notification received to susiMirror object in the renderer module by calling the receivedNotification method of susiMirror object

We can now receive all the notifications in the SusiMirror and update UI. To handle notifications, we define receivedNotification method as follows:

public receivedNotification(type: NotificationType, payload: any): void {

   switch (type) {
       case "idle":
            // handle idle state
       case "listening":
           // handle listening state
       case "busy":
           // handle busy state
       case "recognized":
           // handle recognized state. This notification also contains a payload about the hypothesis text           
       case "speak":
           // handle speaking state. We need to play back audio file and display text on screen for SUSI Output. Notification Payload contains SUSI Response

In this way, we utilize the Socket Notification System provided by the MagicMirror Electron Application to send data across the components of Magic Mirror module for SUSI AI.


How Meilix Generator sends Email Notifications with SendGrid

We wanted to notify the users once the build was ready for download. To solve this we attempted making an email server on Meilix Generator but that can send email when it starts but it would take around 20 minutes to get the build ready so we thought of checking the deploy link status and send email whenever the link status was available (200) but the problem with this method was that the link can be pre available if ISO is rebuilt for same event.

Then, we attempted sending mail by Travis CI but the problem in that was closed SMTP ports (they have a strict policy about that) then we thought that Travis CI can trigger the Sendgrid which can send email to the user with the help of API.

We will use this code so that once the deployment of ISO by Travis CI is done it can execute the email script which requests Sendgrid to send email to the user.

  - ./


We can create code using code generation service of Sendgrid we are going to choose python as it is easier to manipulate strings in python and we are going to use email as an environment variable.

After generation of python 3 code from the sendgrid website we are going to edit the message and email and hide the API key as an environment variable and create an authorization string to be used there too.

The URL will be generated by the below script as the body of url remains same only two things will change the TRAVIS_TAG which is event name and date.

date ='%Y%m%d')


We can use this to hide the api key and use it as an environment variable because if the api key is visible in logs anyone can use it to exploit it and use it for spamming purpose.

authorization = "Bearer " + os.environ["mail_api_key"]
headers = {
    'authorization': authorization,


The main thing left to edit in the script is the message which is in the payload and is a string type so we are going to use the email received by Meilix generator as an environment variable and concatenate it with the payload string the message sent is in the value which is in the HTML format and we add the generated URL in similar way we added email variable to string.

payload = "{\"personalizations\":[{\"to\":[{\"email\":\"" + os.environ["email"] + "\"}],\"subject\":\"Your ISO is Ready\"}],\"from\":{\"email\":\"[email protected]\",\"name\":\"Meilix Generator\"},\"reply_to\":{\"email\":\"[email protected]\",\"name\":\"Meilix Generator\"},\"subject\":\"Your ISO is ready\",\"content\":[{\"type\":\"text/html\",\"value\":\"<html><p>Hi,<br>Your ISO is ready<br>URL : "+url+"<br><br>Thank You,<br>Meilix Generator Team</p></html>\"}]}"


The sent email looks like this


Mark Notifications Read on Click

Screenshot from 2016-08-01 07:31:22

Notification has become a really important way of informing users about the various activities related to them in web apps. There are different types of notification such as web app notification, email notification, desktop notification, push notification, etc. We are going to primarily talk about web app notification and mainly about how to mark them as read.

Create Notification

Creating a notification is plain and simple. You have a json or an object which stores the notification message corresponding to a particular activity. Whenever that activity occurs in the backend, you call the send notification module, which adds the information to the database and shows it in the notification page. As simple as that.

Screenshot from 2016-08-01 07:48:08

Marking Notification as Read

The main functioning of this is plain and simple as well. You have a URL, which on getting a request from the user, marks the notification as read in the database. That’s it.

Screenshot from 2016-08-01 07:48:17

We know how to do this using a button or a link. But the question here is how to mark a notification as read on clicking any part of the notification?? The obvious answer is, well, put the entire notification inside an anchor tag and you are done, right? Well, it would work in many cases. But what if the design structure is such that this doesn’t work somehow. Somehow enclosing the notification inside a particular anchor tag doesn’t solve the purpose. What do we do then?

Identify Whether Inside a DIV

The main problem here actually is how to identify whether the click is inside the enclosing div or somewhere else. Once we solve this problem, we can send an ajax request to the mark read URL and our job is done.

Screenshot from 2016-08-01 07:52:58

So, to identify that a click is indeed inside a div, we use the property of the event clicked. The target event property returns the element that triggered the event. So we check whether has the “notification” class in our case. If it does not have the “notification” class we check in all it’s parent nodes. We get the parent nodes using the “parent()” function and check whether any of that has notification. If either of the 2 occurs, we consider that the click is inside the div. And thus mark the notification as read.

Screenshot from 2016-08-01 07:51:09

So, once this is done, we mark the notification as read in the backend and our job is done…