Showing Order Details in Eventyay Organizer Android App

In Open Event Organizer App, the organizer was not able to view the details for the Orders received from attendees for his/her events. So in this blog we’ll see how we implemented this functionality in the Orga App.


There is a fragment showing the list of all orders for that event. The user will be able to click on order from the list which will then take the user to another fragment where Order details will be displayed. We will be following MVVM architecture to implement this functionality using REST API provided by Open Event Server. Let’s get started.

Firstly, we will create Order Model class. This contains various fields and relationship attributes to setup the table in database using RazizLabs DbFlow annotations.

Then, We will make a GET request to the server using Retrofit 2  to fetch Order object.

Observable<Order> getOrder(@Path(“identifier”) String identifier);

The server will return the Order details in form of a Order object and then we will save it in local  database so that when there is no network connectivity then also we can show data to the user and user can refresh to fetch the latest data from network. The network observable handles fetching data from network and disk observable handles saving data in local database.

public Observable<Order> getOrder(String orderIdentifier, boolean reload) {
Observable<Order> diskObservable = Observable.defer(() ->
.getItems(Order.class, Order_Table.identifier.eq(orderIdentifier)).take(1)

Observable<Order> networkObservable = Observable.defer(() ->
.doOnNext(order -> repository
.save(Order.class, order)

return repository

Now, we will make a Fragment class that will bind the layout file to the model in the onCreateView method using DataBindingUtil. Further, we will be observing on ViewModel to reflect changes of Order, Progress and Error objects in the UI in the onStart method of the Fragment.

public class OrderDetailFragment extends BaseFragment implements OrderDetailView {

public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
binding = DataBindingUtil.inflate(inflater, R.layout.order_detail_fragment, container, false);

orderDetailViewModel = ViewModelProviders.of(this, viewModelFactory).get(OrderDetailViewModel.class);

return binding.getRoot();

public void onStart() {

orderDetailViewModel.getOrder(orderIdentifier, eventId, false).observe(this, this::showOrderDetails);
orderDetailViewModel.getProgress().observe(this, this::showProgress);
orderDetailViewModel.getError().observe(this, this::showError);

Next, we will create OrderDetailsViewModel.This is the ViewModel class which interacts with the repository class to get data and the fragment class to show that data in UI.

Whenever the user opens Order details page, the method getOrder() twill be called which will request an Order object from OrderRepository, wrap it in MutableLiveData and provide it to Fragment.

Using MutableLiveData to hold the data makes the data reactive i.e. changes in UI are reflected automatically when the object changes. Further, we don’t have to worry handling the screen rotation as LIveData handles it all by itself.

  public LiveData<Order> getOrder(String identifier, long eventId, boolean reload) {
if (orderLiveData.getValue() != null && !reload)
return orderLiveData;

compositeDisposable.add(orderRepository.getOrder(identifier, reload)
.doOnSubscribe(disposable -> progress.setValue(true))
.doFinally(() -> progress.setValue(false))
.subscribe(order -> orderLiveData.setValue(order),
throwable -> error.setValue(ErrorUtils.getMessage(throwable))));

if (!reload) {

return orderLiveData;


  1. Codebase for Open Event Orga App
  2. Official documentation for LiveData Architecture Component
  3. Official Github Repository of Retrofit
  4. Official Github Repository for RxJava
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Adding a Countdown to Orders Page in Open Event Frontend

This blog post will illustrate how you can add a countdown to orders page which on finishing expires the ticket in Open Event. In Open Event we allow some predefined time for users to fill in their details and once the time expires order gets expired and tickets get released. Users can order the tickets again if they want.

We start by adding a createdAt field to orders model so that we can keep track of remaining time. To calculate the time when the order should expire we add predefined time in which user should fill their details to createdAt time. In this way, we get the time when the order will expire.

So now to calculate the remaining time we just subtract the expiring time from current time. And then we render this data into the template. We define getRemainingTime property in our template and fetch the data for that property with help of javascript.

To see the template code visit this link.

The challenge here is to update the time remaining after every second. For this, we take the help of ember runloop. The run.later() function of ember runloop helps us to calculate the property after every second and set it. Code for setting the remaining time with the help of javascript is given below.

// app/components/forms/orders/order-form.js

getRemainingTime: computed('data', function() {
    let willExpireAt = this.get('data.createdAt').add(10, 'minutes');
    this.timer(willExpireAt, this.get('data.identifier'));

  timer(willExpireAt, orderIdentifier) {
    run.later(() => {
      let currentTime = moment();
      let diff = moment.duration(willExpireAt.diff(currentTime));
      this.set('getRemainingTime', moment.utc(diff.asMilliseconds()).format('mm:ss'));
      if (diff > 0) {
        this.timer(willExpireAt, orderIdentifier);
      } else {
        this.get('router').transitionTo('orders.expired', orderIdentifier);
    }, 1000);


As given in the code. We pass expiring time and order’s model instance to the timer function. Timer function calculates the remaining time and sets it to getRemainingTime property of template. Timer function runs after every second with the help of run.later() function of ember runloop. To format the remaining time into MM:SS we take help of moment.js library and format the data accordingly.

Once the remaining time is less than zero (time expires) we reload the model and transition current route to expired route. We do not have to set order status as expired inside the FE. Server sets the order as expired after the predefined time. So we just reload the model from the server and we get the updated status of the order.

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Adding Helper and Adding Action Buttons to Orders List in Open Event Frontend

This blog post will illustrate how to add a helper to orders list and add action buttons to orders list to delete and cancel an order in Open Event Frontend. To cancel or delete an order item we need to communicate to the server. The API endpoints to which we communicate are:

  • PATCH        /v1/orders/{order_identifier}
  • DELETE    /v1/orders/{orders_identifier}

We will define the action buttons in ui-table component of open event frontend. We will use the cell-actions file to define the cell buttons that will be present in cell-actions column. The following handlebars code will render the buttons on website.


class="ui vertical compact basic buttons"> {{#if (and (not-eq record.status 'cancelled') (can-modify-order record))}} {{#ui-popup content=(t 'Cancel order') click=(action (confirm (t 'Are you sure you would like to cancel this Order?') (action cancelOrder record))) class='ui icon button' position='left center'}} class="delete icon"> {{/ui-popup}} {{/if}} {{#if (can-modify-order record)}} {{#ui-popup content=(t 'Delete order') click=(action (confirm (t 'Are you sure you would like to delete this Order?') (action deleteOrder record))) class='ui icon button' position='left center'}} class="trash icon"> {{/ui-popup}} {{/if}} {{#ui-popup content=(t 'Resend order confirmation') class='ui icon button' position='left center'}} class="mail outline icon"> {{/ui-popup}}


In above code you can see two things. First is can-modify-order which is a helper. Helper is used to simplify conditional logics which cannot be easily placed in handlebars. Second thing is action. There are two actions defined: cancelOrder and deleteOrder. We will see implementation of these later. First let’s see how we define can-modify-order helper.

In can-modify-order helper we want to return true or false in case we want cancel button and delete button to display or not respectively. We write the code of can-modify-order in helpers/can-modify-order.js file. When we want to get result from this helper we call it from handlebars file and pass any parameter that we want to use in helper. Code for can-modify-order helper is given below.

// helpers/can-modify-order.js

import Helper from '@ember/component/helper';

export function canModifyOrder(params) {
 let [order] = params;
 if (order.amount !== null && order.amount > 0) {
   // returns false if order is paid and completed
   return order.status !== 'completed';
 // returns true for free ticket
 return true;

export default Helper.helper(canModifyOrder);


We extract the parameter and store it in order variable. We see if it satisfies our conditions we return true else false.

Now lets see how we can define actions to perform delete and cancel action on a order. We define these actions in controllers section of app. After performing suitable operation with order we call save to update modified order and destroyRecord() to delete an order. Let see the code implementation for these actions.

actions: {
   deleteOrder(order) {
     this.set('isLoading', true);
       .then(() => {
         this.notify.success(this.get('l10n').t('Order has been deleted successfully.'));
       .catch(() => {
         this.notify.error(this.get('l10n').t('An unexpected error has occurred.'));
       .finally(() => {
         this.set('isLoading', false);
   cancelOrder(order) {
     this.set('isLoading', true);
     order.set('status', 'cancelled');
       .then(() => {
         this.notify.success(this.get('l10n').t('Order has been cancelled successfully.'));
       .catch(() => {
         this.notify.error(this.get('l10n').t('An unexpected error has occurred.'));
       .finally(() => {
         this.set('isLoading', false);

After defining these actions, buttons in the orders list start working. In this way, we can make use of helper to simplify the conditional logic inside templates and define proper actions.

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Integrating Orders API to Allow User Select Tickets for Placing Order in Open Event Frontend

In Open Event Frontend organizer has option to sell tickets for his event. Tickets which are available to public are listed in public page of event for users to buy. In this blog post we will learn how to integrate orders API and manage multiple tickets of varying quantity under an order.

For orders we mainly interact with three API endpoints.

  1. Orders API endpoint
  2. Attendees API endpoint
  3. Tickets API endpoint

Orders and attendees have one to many relationship and similarly orders and tickets also have one to many relationship. Every attendee is related to one ticket. In simple words one attendee has one ticket and one order can contain many tickets of different quantity each meant for different attendee.

// routes/public/index.js

order:'order', {
  event     : eventDetails,
  user      : this.get('authManager.currentUser'),
  tickets   : [],
  attendees : []


We need to create instance of order model to fill in data in that record. We do this in our routes folder of public route. Code snippet is given below.

We create a empty array for tickets and attendees so that we can add their record instances as relationship to order.

As given in screenshot we have a dropdown for each ticket to select quantity of each ticket. To allow user select quantity of a ticket we use #ui-dropdown component of ember-semantic-ui in our template. The code snippet of that is given below.

// templates/components/public/ticket-list.js

{{#ui-dropdown class='compact selection' forceSelection=false onChange=(action 'updateOrder' ticket) as |execute mapper|}}
  {{input type='hidden' id=(concat '_quantity') value=ticket.orderQuantity}}
    <i class="dropdown icon"></i>
class="default text">0
class="item" data-value="{{map-value mapper 0}}">{{0}}
{{#each (range ticket.minOrder ticket.maxOrder) as |count|}}
class="item" data-value="{{map-value mapper count}}">{{count}}
{{/each}} </div> {{/ui-dropdown}}


For every change in quantity of ticket selected we call a action named updateOrder. The code snippet for this action is given below.

// components/public/ticket-list.js

updateOrder(ticket, count) {
      let order = this.get('order');
      ticket.set('orderQuantity', count);
      order.set('amount', this.get('total'));
      if (count > 0) {;
      } else {
        if ( {


Here we can see that if quantity of selected ticket is more than 0 we add that ticket to our order otherwise we remove that ticket from the order if it already exists.

Once user selects his tickets for the order he/she can order the tickets. On clicking Order button we call placeOrder action. With help of this we add all the relations and finally send the order information to the server. Code snippet is given below.

// components/public/ticket-list.js
placeOrder() {
   let order = this.get('order');
   let event = order.get('event'); => {
     let attendee = ticket.orderQuantity;
     let i;
     for (i = 0; i < attendee; i++) {
       order.attendees.addObject('attendee', {
         firstname : 'John',
         lastname  : 'Doe',
         email     : '[email protected]',


Here for each ticket placed under an order we create a dummy attendee related to ticket and event. And then we call save action to save all the models. Code snippet for save is given:

actions: {
    async save() {
      try {
        this.set('isLoading', true);
        let order = this.get('model.order');
        let attendees = order.get('attendees');
        attendees.forEach(async attendee => {
          .then(order => {
            this.get('notify').success(this.get('l10n').t('Order created.'));
      } catch (e) {
        this.get('notify').error(this.get('l10n').t('Oops something went wrong. Please try again'));


Here we finally save all the models and transition to orders page to enable user fill the attendees details.

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Open Event Server – Export Orders as CSV File

FOSSASIA‘s Open Event Server is the REST API backend for the event management platform, Open Event. Here, the event organizers can create their events, add tickets for it and manage all aspects from the schedule to the speakers. Also, once he/she makes his event public, others can view it and buy tickets if interested.

The organizer can see all the orders in a very detailed view in the event management dashboard. He can see the statuses of all the orders. The possible statuses are completed, placed, pending, expired and canceled.

If the organizer wants to download the list of all the orders as a CSV file, he or she can do it very easily by simply clicking on the Export As and then on CSV.

Let us see how this is done on the server.

Server side – generating the Orders CSV file

Here we will be using the csv package provided by python for writing the csv file.

import csv
  • We define a method export_orders_csv which takes the orders to be exported as a CSV file as the argument.
  • Next, we define the headers of the CSV file. It is the first row of the CSV file.
def export_orders_csv(orders):
   headers = ['Order#', 'Order Date', 'Status', 'Payment Type', 'Total Amount', 'Quantity',
              'Discount Code', 'First Name', 'Last Name', 'Email']
  • A list is defined called rows. This contains the rows of the CSV file. As mentioned earlier, headers is the first row.
rows = [headers]
  • We iterate over each order in orders and form a row for that order by separating the values of each of the columns by a comma. Here, every row is one order.
  • The newly formed row is added to the rows list.
for order in orders:
   if order.status != "deleted":
       column = [str(order.get_invoice_number()), str(order.created_at) if order.created_at else '',
                 str(order.status) if order.status else '', str(order.paid_via) if order.paid_via else '',
                 str(order.amount) if order.amount else '', str(order.get_tickets_count()),
                 str(order.discount_code.code) if order.discount_code else '',
                 if order.user and order.user.first_name else '',
                 if order.user and order.user.last_name else '',
                 str( if order.user and else '']
  • rows contains the contents of the CSV file and hence it is returned.
return rows
  • We iterate over each item of rows and write it to the CSV file using the methods provided by the csv package.
writer = csv.writer(temp_file)
from app.api.helpers.csv_jobs_util import export_orders_csv
content = export_orders_csv(orders)
for row in content:

Obtaining the Orders CSV file:

Firstly, we have an API endpoint which starts the task on the server.

GET - /v1/events/{event_identifier}/export/orders/csv

Here, event_identifier is the unique ID of the event. This endpoint starts a celery task on the server to export the orders of the event as a CSV file. It returns the URL of the task to get the status of the export task. A sample response is as follows:

  "task_url": "/v1/tasks/b7ca7088-876e-4c29-a0ee-b8029a64849a"

The user can go to the above-returned URL and check the status of his/her Celery task. If the task completed successfully he/she will get the download URL. The endpoint to check the status of the task is:

and the corresponding response from the server –

  "result": {
    "download_url": "/v1/events/1/exports/http://localhost/static/media/exports/1/zip/OGpMM0w2RH/"
  "state": "SUCCESS"

The file can be downloaded from the aabove-mentionedURL.


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Implementing Permissions for Orders API in Open Event API Server

Open Event API Server Orders API is one of the core APIs. The permissions in Orders API are robust and secure enough to ensure no leak on payment and ticketing.The permission manager provides the permissions framework to implement the permissions and proper access controls based on the dev handbook.

The following table is the permissions in the developer handbook.


List View Create Update Delete
Event organizer [1] [1] [1] [1][2] [1][3]
Registered user [4]
Everyone else
  1. Only self-owned events
  2. Can only change order status
  3. A refund will also be initiated if paid ticket
  4. Only if order placed by self

Super Admins and admins are allowed to create any order with any amount but any coupon they apply is not consumed on creating order. They can update almost every field of the order and can provide any custom status to the order. Permissions are applied with the help of Permission Manager which takes care the authorization roles. For example, if a permission is set based on admin access then it is automatically set for super admin as well i.e., to the people with higher rank.

Self-owned events

This allows the event admins, Organizer and Co-Organizer to manage the orders of the event they own. This allows then to view all orders and create orders with or without discount coupon with any custom price and update status of orders. Event admins can provide specific status while others cannot

if not has_access('is_coorganizer', event_id=data['event']):
   data['status'] = 'pending'

And Listing requires Co-Organizer access

elif not has_access('is_coorganizer', event_id=kwargs['event_id']):
   raise ForbiddenException({'source': ''}, "Co-Organizer Access Required")

Can only change order status

The organizer cannot change the order fields except the status of the order. Only Server Admin and Super Admins are allowed to update any field of the order.

if not has_access('is_admin'):
   for element in data:
       if element != 'status':
           setattr(data, element, getattr(order, element))

And Delete access is prohibited to event admins thus only Server admins can delete orders by providing a cancelling note which will be provided to the Attendee/Buyer.

def before_delete_object(self, order, view_kwargs):
   if not has_access('is_coorganizer',
       raise ForbiddenException({'source': ''}, 'Access Forbidden')

Registered User

A registered user can create order with basic details like the attendees’ records and payment method with fields like country and city. They are not allowed to provide any custom status to the order they are creating. All orders will be set by default to “pending”

Also, they are not allowed to update any field in their order. Any status update will be done internally thus maintaining the security of Order System. Although they are allowed to view their place orders. This is done by comparing their logged in user id with the user id of the purchaser.

if not has_access('is_coorganizer_or_user_itself', event_id=order.event_id, user_id=order.user_id):
   return ForbiddenException({'source': ''}, 'Access Forbidden')

Event Admins

The event admins have one more restriction, as an event admin, you cannot provide discount coupon and even if you do it will be ignored.

# Apply discount only if the user is not event admin
if data.get('discount') and not has_access('is_coorganizer', event_id=data['event']):

Also an event admin any amount you will provide on creating order will be final and there will be no further calculation of the amount will take place

if not has_access('is_coorganizer', event_id=data['event']):

Creating Attendees Records

Before sending a request to Orders API it is required to create to attendees mapped to some ticket and for this registered users are allowed to create the attendees without adding a relationship of the order. The mapping with the order is done internally by Orders API and its helpers.


  1. Dev Handbook – Niranjan R
    The Open Event Developer Handbook
  2. Flask-REST-JSONAPI Docs
    Permissions and Data layer | Flask-REST-JSONAPI
  3. A guide to use permission manager in API Server


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