Testing the ViewModels in Open Event Organizer App

In Open Event Organizer Android App we follow Test Driven Development Approach which means the features added in the app are tested thoroughly by unit tests. More tests would ensure better code coverage and fewer bugs. This blog explains how to write tests for Viewmodel class in MVVM architecture.

Specifications

We will use JUnit4 to write unit tests and Mockito for creating mocks. The OrdersViewModel class returns the list of Order objects to the Fragment class. The objects are requested from OrderRepository class which fetches them from Network and Database. We will create a mock of OrderRepository class since it is out of context and contain logic that doesn’t depend on Orders Respository. Below is the getOrders method that we will test.

 public LiveData<List<Order>> getOrders(long id, boolean reload) {
if (ordersLiveData.getValue() != null && !reload)
return ordersLiveData;

compositeDisposable.add(orderRepository.getOrders(id, reload)
.compose(dispose(compositeDisposable))
.doOnSubscribe(disposable -> progress.setValue(true))
.doFinally(() -> progress.setValue(false))
.toList()
.subscribe(ordersLiveData::setValue,
throwable -> error.setValue(ErrorUtils.getMessage(throwable).toString())));

return ordersLiveData;
}

We will be using InstantTaskExecutorRule() which is a JUnit Test Rule that swaps the background executor used by the Architecture Components with a different one which executes each task synchronously. We will use setUp() method to load the RxJavaPlugins, RxAndroid plugins and reset them in tearDown method which will ensure each test runs independently from the other and avoid memory leaks. After doing this initialization and basic setup for tests we can begin code the method shouldLoadOrdersSuccessfuly() to test the getOrders method present in ViewModel class. Let’s see the step by step approach.

  1. Use Mockito.when to return Observables one by one from ORDERS_LIST whenever the method getOrders of the mock orderRepository is called.
  2. We will use Mockito.InOrder and pass orders, orderRepository and progress to check if they are called in a particular order.
  3. We will use .observeForever method to observe on LiveData objects and add a ArrayList on change.
  4. Finally, we will test and verify if the methods are called in order.
@Test
public void shouldLoadOrdersSuccessfully() {
when(orderRepository.getOrders(EVENT_ID, false))
.thenReturn(Observable.fromIterable(ORDERS_LIST));

InOrder inOrder = Mockito.inOrder(orders, orderRepository, progress);

ordersViewModel.getProgress().observeForever(progress);

orders.onChanged(new ArrayList<>());

ordersViewModel.getOrders(EVENT_ID, false);

inOrder.verify(orders).onChanged(new ArrayList<>());
inOrder.verify(orderRepository).getOrders(EVENT_ID, false);
inOrder.verify(progress).onChanged(true);
inOrder.verify(progress).onChanged(false);
}

Similar approach can be followed for writing tests to check other behaviour of the ViewModel.

References

  1. Official Documentation for testing. https://developer.android.com/reference/android/arch/core/executor/testing/InstantTaskExecutorRule
  2. Official Documentation for JUnit.  https://junit.org/junit4/
  3. Official documentation for Mockito.  http://site.mockito.org/
  4. Open Event Organizer App codebase.  https://github.com/fossasia/open-event-orga-app
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Swipe to Check In/Out in Open Event Organizer App

Open Event Organizer App didn’t provide any option for the Event Organizer to view the list of Attendees present under an Order and check them in/out the event. Therefore, we designed a system such that the Organizer can just swipe the attendee present under an order to check them in or out. In this blog post, I will discuss how we implemented this functionality in Open Event Organizer App without using any third party libraries.

Specifications

We will create a separate class SwipeController.java which extends ItemTouchHelper.SimpleCallback and provide the swiping functionalities to our plain old recyclerview. We will call the super constructor with ItemTouchHelper.LEFT and ItemTouchHelper.RIGHT as arguments to provide left as well as right movements in each recyclerview list item. The bitmaps and paint object initialized here will be used later in onDraw.

public SwipeController(OrderDetailViewModel orderDetailViewModel, OrderAttendeesAdapter orderAttendeesAdapter, Context context) {
super(0, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT);
this.orderDetailViewModel = orderDetailViewModel;
this.orderAttendeesAdapter = orderAttendeesAdapter;

closeIcon = BitmapFactory.decodeResource(context.getResources(), R.drawable.close);
doneIcon = BitmapFactory.decodeResource(context.getResources(), R.drawable.done);

paintGreen.setColor(context.getResources().getColor(R.color.light_green_500));
paintRed.setColor(context.getResources().getColor(R.color.red_500));
}

Next, we will override getMovementFlags method. This method decides the allowed movement directions for each recyclerview item. The deciding logic is that, if an attendee is checked in then the allowed movement is left to check out and if an attendee is checked out then the allowed movement is right to check in. If neither of the above case, then both movements are allowed.

@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
int dragFlags = 0;

If (orderDetailViewModel.getCheckedInStatus(

viewHolder.getAdapterPosition()) == null)
makeMovementFlags(dragFlags, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT);

if (orderDetailViewModel.getCheckedInStatus(

viewHolder.getAdapterPosition())) {
return makeMovementFlags(dragFlags, ItemTouchHelper.LEFT);
} else {
return makeMovementFlags(dragFlags, ItemTouchHelper.RIGHT);
}
}

The onChildDraw method involves the code doing actual drawing. The variables used in code are discussed below.

  1. ActionState – Checks the state of the recycler view item. We proceed with the below logic if the item is being swiped.
  2. dX – The distance by which the item is swiped. Positive for left and negative for right.
  3. Background – Background of the viewholder. Rectangular in shape and dimensions changed with change in dX.
  4. IconDest – Calculates the position where the icons (close icon or done icon) is placed in canvas
  5. Canvas – Java Canvas on which the drawing is done. We set the background and draw the bitmaps on their location in canvas.
@Override
public void onChildDraw(Canvas canvas, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder,
float dX, float dY, int actionState, boolean isCurrentlyActive) {
if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
View itemView = viewHolder.itemView;
float height = (float) itemView.getBottom() – (float) itemView.getTop();
float width = height / 3;
RectF background;
Paint paint;
Bitmap icon;
RectF iconDest;

if (dX > 0) {
background = new RectF((float) itemView.getLeft(), (float) itemView.getTop(), dX,
(float) itemView.getBottom());
paint = paintGreen;
icon = doneIcon;
iconDest = new RectF((float) itemView.getLeft() + width,
(float) itemView.getTop() + width, (float) itemView.getLeft() + 2 * width,
(float) itemView.getBottom() – width);
} else {
background = new RectF((float) itemView.getRight() + dX, (float) itemView.getTop(),
(float) itemView.getRight(), (float) itemView.getBottom());
paint = paintRed;
icon = closeIcon;
iconDest = new RectF((float) itemView.getRight() – 2 * width,
(float) itemView.getTop() + width, (float) itemView.getRight() – width,
(float) itemView.getBottom() – width);
}

canvas.drawRect(background, paint);
canvas.drawBitmap(icon, null, iconDest, paint);
}
super.onChildDraw(canvas, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}

Now after the item is swiped out or in, we need to restore its original state again. For this we override the onSwiped method and call notifyItemChanged(). Also, the changes in UI (showing green side strip for checked in and red side strip for checked out) are done by. We call the toggleCheckin() method in ViewModel to toggle the checking status of the attendee in server and local database.

@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
int position = viewHolder.getAdapterPosition();

orderDetailViewModel.toggleCheckIn(position);
orderAttendeesAdapter.notifyItemChanged(position);
}

Last but not the least, we will override the onMove method to return false. Since we are not supporting drag and drop features therefore this method will never be called.

@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return false;
}

Resources

  1. Codebase for Open Event Organizer App https://github.com/fossasia/open-event-orga-app
  2. Official documentation for ItemTouchHelper.SimpleCallback https://developer.android.com/reference/android/support/v7/widget/helper/ItemTouchHelper.SimpleCallback
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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.

Specifications

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.

@GET(“orders/{identifier}?include=event”)
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.

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

Observable<Order> networkObservable = Observable.defer(() ->
orderApi.getOrder(orderIdentifier)
.doOnNext(order -> repository
.save(Order.class, order)
.subscribe()));

return repository
.observableOf(Order.class)
.reload(reload)
.withDiskObservable(diskObservable)
.withNetworkObservable(networkObservable)
.build();
}

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 {

@Override
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();
}

@Override
public void onStart() {
super.onStart();
setupRefreshListener();

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)
.compose(dispose(compositeDisposable))
.doOnSubscribe(disposable -> progress.setValue(true))
.doFinally(() -> progress.setValue(false))
.subscribe(order -> orderLiveData.setValue(order),
throwable -> error.setValue(ErrorUtils.getMessage(throwable))));

if (!reload) {
getEvent(eventId);
}

return orderLiveData;
}
}

References

  1. Codebase for Open Event Orga App https://github.com/fossasia/open-event-orga-app
  2. Official documentation for LiveData Architecture Component https://developer.android.com/topic/libraries/architecture/livedata
  3. Official Github Repository of Retrofit  https://github.com/square/retrofit
  4. Official Github Repository for RxJava https://github.com/ReactiveX/RxJava
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Share Events in the Open Event Organizer Android App

In the Open Event Organizer Android App, after creating an event the organizer was unable to share it. We handled this challenge and came up with options to share Event with other social media apps. Along with that user can send Email to users containing event description with just a click. All this through a UI that our user will love interacting with. Let’s see how we implemented this.

Specifications

We designed a UI given below which offer four functionalities to the user in a single screen.

  1. The Event Name and Date are shown in the CardView.
  2. User can copy Event External URL by clicking on Copy URL option.
  3. User can send Email containing information about the Event like ( Name, Description, Starting and Ending Date-Time for the Event) via Email by clicking on Email option.
  4. User can share the same information described in point three via other social media/chatting apps etc by clicking on many more option.

The is the Event Model class ia a POJO containing the associated attributes.

We will use Retrofit to fetch Event object from server through a GET request in EventApi class.

@GET(“events/{id}?include=tickets”)
Observable<Event> getEvent(@Path(“id”) long id);

Then we will use the getEvent method of EventRepositoryImpl class to make the request for us using EventApi class and then pass on the Response Event object to the ViewModel by wrapping it in RxJava Observable. We are accepting a boolean field named reload which decdes whether we need to reuse the existing Event object from Local Database  or fetch a new object from server.

@Override
public Observable<Event> getEvent(long eventId, boolean reload) {
Observable<Event> diskObservable = Observable.defer(() ->
repository
.getItems(Event.class, Event_Table.id.eq(eventId))
.filter(Event::isComplete)
.take(1)
);

Observable<Event> networkObservable = Observable.defer(() ->
eventApi
.getEvent(eventId)
.doOnNext(this::saveEvent));

return repository.observableOf(Event.class)
.reload(reload)
.withDiskObservable(diskObservable)
.withNetworkObservable(networkObservable)
.build();
}

In ShareEventVewModel, we are calling the getEvent from EventRepositoryImpl class, construct a LiveData object from it so that UI could observe changes on it. Methods getShareableInformation, getShareableUrl, getShareableSubject provide the shareable information to the UI which is further shared with other apps.

public class ShareEventViewModel extends ViewModel {

protected LiveData<Event> getEvent(long eventId, boolean reload) {
if (eventLiveData.getValue() != null && !reload)
return eventLiveData;

compositeDisposable.add(eventRepository.getEvent(eventId, reload)
.doOnSubscribe(disposable -> progress.setValue(true))
.doFinally(() -> progress.setValue(false))
.subscribe(event -> {
this.event = event;
eventLiveData.setValue(event);
},
throwable -> error.setValue(ErrorUtils.getMessage(throwable))));

return eventLiveData;
}

public String getShareableInformation() {
return Utils.getShareableInformation(event);
}

}

In ShareEventFragment class does the work of binding the UI to the model using data binding. It observes the LiveData objects supplied by presenter and reflect the changes in UI to the LiveData object.

public class ShareEventFragment extends BaseFragment implements ShareEventView {

public void shareEvent() {
Intent shareIntent = new Intent();
shareIntent.setAction(Intent.ACTION_SEND);
shareIntent.putExtra(Intent.EXTRA_TEXT, shareEventViewModel.getShareableInformation());
shareIntent.setType(“text/plain”);
startActivity(Intent.createChooser(shareIntent, getResources().getText(R.string.send_to)));
}

public void shareByEmail() {
Intent shareIntent = new Intent();
shareIntent.setAction(Intent.ACTION_SENDTO);
shareIntent.setType(“message/rfc822”);
shareIntent.setData(Uri.parse(“mailto:”));
shareIntent.putExtra(Intent.EXTRA_SUBJECT, shareEventViewModel.getEmailSubject());
shareIntent.putExtra(Intent.EXTRA_TEXT, shareEventViewModel.getShareableInformation());
try {
startActivity(Intent.createChooser(shareIntent, getResources().getText(R.string.send_to)));
} catch (android.content.ActivityNotFoundException ex) {
ViewUtils.showSnackbar(binding.getRoot(), “There are no email clients installed”);
}
}

public void copyUrlToClipboard() {
ClipboardManager clipboard = (ClipboardManager) getActivity().getSystemService(Context.CLIPBOARD_SERVICE);
String eventUrl = shareEventViewModel.getShareableUrl();
if (eventUrl == null) {
ViewUtils.showSnackbar(binding.getRoot(), “Event does not have a Public URL”);
} else {
ClipData clip = ClipData.newPlainText(“Event URL”, shareEventViewModel.getShareableUrl());
clipboard.setPrimaryClip(clip);
ViewUtils.showSnackbar(binding.getRoot(), “Event URL Copied to Clipboard”);
}
}
}

The layout file contains the Event object bind to the UI using Two way Data Binding. Here is an extract from the layout file. For viewing entire file, please refer here.

References

  1. Official documentation of Retrofit 2.x http://square.github.io/retrofit/
  2. Official documentation for RxJava 2.x https://github.com/ReactiveX/RxJava
  3. Official documentation for ViewModel https://developer.android.com/topic/libraries/architecture/viewmodel
  4. Codebase for Open Event Organizer App https://github.com/fossasia/open-event-orga-app
Continue Reading

Create Session in Open Event Android Organizer Application

Open Event Android Organizer Application offered variety of features to Organizers from all over the world to help them host their Events globally but it didn’t had the functionality to create Sessions in the app itself and associate it to Tracks. This feature addition was crucial since it enables Organizer to create Sessions which every common person enquires about before attending and event. In this Blog Post we will see how we added this functionality in the app.

Open Event Android Organizer Application is a client for Open Event Server which provides the REST API.

Problem

There can be various Sessions associated with Tracks for an Event. Open Event API had the endpoint to implement Creating Session but the Orga app didn’t, so we worked on creating a Session in the app.

The UI for creating a Session is shown above. User can fill in the necessary details and click on the green Floating Action Button to create a Session.

How to implement functionality?

We will follow MVP Architecture and use Retrofit 2.x, RxJava, Dagger, Jackson, Data Binding and other industry standard libraries to implement this functionality.

Firstly, let’s create Session model class specifying the attributes and relationships to set up in database using RazizLabs DbFlow library. The POJO will be serialized into JSON by Jackson library to be passed on as a part of RequestBody to server.

Now we will create SessionApi class that will contain the request details to be passed to Retrofit. @POST denotes a POST request and @Body denotes the requestBody of the request which is a Session object.

public interface SessionApi {
@POST(“sessions”)
Observable<Session> postSession(@Body Session session);
}

This is the CreateSessionFragment class that contains the code binding model to the view. The Fragment class implements the CreateSessionView class overriding the method declarations present there. The @Inject annotation of Dagger is used to load singleton presenter instance lazily to improve app’s performance.

Event-Id and Track-Id’s are retrieved from Bundle from Fragment Transaction. These are then passed on to presenter when Create Session button is pressed. There are other methods to show binding progressbar, snackbar and other UI components to show progress of the background request to server and database.

public class CreateSessionFragment extends BaseFragment<CreateSessionPresenter> implements CreateSessionView {

@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup

container, @Nullable Bundle savedInstanceState) {
binding = DataBindingUtil.inflate(inflater,

R.layout.session_create_layout, container, false);
validator = new Validator(binding.form);

binding.sessionCreate.setOnClickListener(view -> {
if (validator.validate()) {
getPresenter().createSession(trackId, eventId);
}
});

return binding.getRoot();
}

@Override
public void onStart() {
super.onStart();
getPresenter().attach(this);
binding.setSession(getPresenter().getSession());
}
}

In the Presenter createSession method is called when create button is pressed in UI. The method attaches track-id and event-id to Session object. This is necessary for Relationship constraints on Session Model. Then after binding all the data to Session object, we pass it on to SessionRepository. The success response is provided to user by passing success response in getView().onSuccess() method.

public class CreateSessionPresenter extends

AbstractBasePresenter<CreateSessionView> {

public Session getSession() {
return session;
}

public void createSession(long trackId, long eventId) {

Track track = new Track();
Event event = new Event();

track.setId(trackId);
event.setId(eventId);
session.setTrack(track);
session.setEvent(event);

sessionRepository
.createSession(session)
.compose(dispose(getDisposable()))
.compose(progressiveErroneous(getView()))
.subscribe(createdSession ->

getView().onSuccess(“Session Created”), Logger::logError);
}
}

The SessionRepository uses RxJava to make asynchronous Retrofit Call to Server. We throw a Network Error to user if the device does not have Internet Connectivity.

The session object accepted as a parameter in createSession method is passed on to sessionApi. It will return Observable<Session> Response which we will process in doOnNext() method. Then the Session object along with required foreign key relationships with Track and Event is saved in database for offline use.

@Override
public Observable<Session> createSession(Session session) {
if (!repository.isConnected()) {
return Observable.error(new Throwable(Constants.NO_NETWORK));
}return sessionApi
.postSession(session)
.doOnNext(created -> {
created.setTrack(session.getTrack());
created.setEvent(session.getEvent());
repository
.save(Session.class, created)
.subscribe();
})
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread());
}

The above code snippets are from Open Event Orga Application. For exploring the entire codebase please refer here. For details about the REST API used by the app please visit here.

References

  1. Official RxJava Project on Github by ReactiveX https://github.com/ReactiveX/RxJava.
  2. Official Retrofit Project on Github by Square Inc https://github.com/square/retrofit.
  3. Official Open Event Organizer App on Github by FOSSASIA https://github.com/fossasia/open-event-orga-app.
  4. Documentation for REST API of Open Event Server on Heroku by FOSSASIA https://open-event-api-dev.herokuapp.com/.
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Adding Marketer and Sales Admin Events Relationship with User on Open Event Server

In this blog, we will talk about how to add API for adding and displaying events in with a user acts as a Marketer and/or Sales Admin on Open Event Server. The focus is on Model Updation and Schema updation of User.

Model Updation

For the Marketer and Sales Admin events, we’ll update User model as follows

Now, let’s try to understand these relationships.

In this feature, we are providing user to act as a marketer and sales admin for a event.

  1. Both the relationships will return the events in which the user is acting as a Marketer and/or Sales Admin.
  2. There are two custom system roles in model CustomSysRole which are Marketer and Sales Admin. A user can act as these custom system roles with respect to an event.
  3. In this relationship, we will return those events from UserSystemRole model in which a user is acting as Marketer Custom System Role and Sales Admin Custom System Role.
  4. We make use of Event and join UserSystemRole and CustomSysRole where we use that user where UserSystemRole.user_id == User.id , CustomSysRole.id == UserSystemRole.role_id, CustomSysRole.name == “Sales Admin” and then we return events in which Event.id == UserSystemRole.event_id
  5. Similarly, for Marketer events we make use of Event and join UserSystemRole and CustomSysRole where we use that user where UserSystemRole.user_id == User.id , CustomSysRole.id == UserSystemRole.role_id, CustomSysRole.name == “Marketer” and then we return events in which Event.id == UserSystemRole.event_id

Schema Updation

For the Marketer and Sales Admin events, we’ll update UserSchema as follows

Now, let’s try to understand this Schema.

In this feature, we are providing user to act as a marketer and sales admin for a event.

  1. For displaying marketer_events relation self_view is displayed by API v1.user_marketer_events and collection of these events is displayed by API v1.event_list
  2. These APIs will return the Events as schema=”EventSchema”. Here, many=True tells us that this is One to many relationship with Events model.

So, we saw how an user can act as a marketer and/or sales admin for many events.

Resources

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Adding Custom System Roles in Open Event Server

In this blog, we will talk about how to add different custom system roles concerning a user on Open Event Server. The focus is on its model and Schema updation.

Model Updation

For the User Table, we’ll update our User Model as follows:

Now, let’s try to understand these hybrid properties.

In this feature, we are providing Admin the rights to see whether a user is acting as a Marketer and / or  Sales Admin of any of the event or not. Here, _is__system_role method is used to check whether an user plays a system role like Marketer, Sales Admin or not. This is done by querying the record from UserSystemRole model. If the record is present then the returned value is True otherwise false.

Schema Updation

For the User Model, we’ll update our Schema as follows:

Now, let’s try to understand this Schema.

Since all the properties will return either True or false so these all properties are set to Boolean in Schema.Here dump_only means, we will return this property in the Schema.

So, we saw how User Model and Schema is updated to show custom system roles concerning a user on Open Event Server.

Resources

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Onsite Attendee in Open Event Server

The Open Event Server enables organizers to manage events from concerts to conferences and meetups. It offers features for events with several tracks and venues. The Event organizers may add orders on behalf of others and accept payments onsite. This blog post goes over the implementation of the onsite attendee feature in the Open Event Server.

Route

Normally we expect the payload for a POST request of order to contain already created attendees also. In this case we want to create the attendees internally inside the server. Hence we need some way to differentiate between the two types of orders. The most basic and easy to implement option is to use a query parameter to specify if the attendees are onsite or not. We use ?onsite=true in order to specify that the attendees are onsite and hence should be created internally.

In the POST request, we check if the query parameters contains the onsite param as true or not. If it is true then we create the attendees using a helper function. The helper function will be discussed in detail later in the article.

# Create on site attendees.
if request.args.get('onsite', False):
    create_onsite_attendees_for_order(data)
elif data.get('on_site_tickets'):
    del data['on_site_tickets']
require_relationship(['ticket_holders'], data)

 

OnsiteTicketSchema

In order to create attendees on the server, we need the information about each ticket bought and it’s quantity. This data is expected in the format declared in the OnsiteTicketSchema.

class OnSiteTicketSchema(SoftDeletionSchema):
    class Meta:
        type_ = 'on-site-ticket'
        inflect = dasherize

    id = fields.Str(load_only=True, required=True)
    quantity = fields.Str(load_only=True, required=True)

Creating onsite Attendees

Following are the few points which we need to focus on when creating onsite attendees:

  1. Validate if the ticket’s data is provided or not. We raise an error if the ticket data is not provided.
  2. Verify if the ticket is sold out or not. We raise an error if the ticket is sold out.
  3. In case an error is raised in any step then we delete the already created attendees. This is a very important point to keep in mind.

if not on_site_tickets:
        raise UnprocessableEntity({'pointer': 'data/attributes/on_site_tickets'}, 'on_site_tickets info missing')

ticket_sold_count = get_count(db.session.query(TicketHolder.id).
                                      filter_by(ticket_id=int(ticket.id), deleted_at=None))

        # Check if the ticket is already sold out or not.
        if ticket_sold_count + quantity > ticket.quantity:
            # delete the already created attendees.
            for holder in data['ticket_holders']:
                ticket_holder = db.session.query(TicketHolder).filter(id == int(holder)).one()
                db.session.delete(ticket_holder)
                try:
                    db.session.commit()
                except Exception as e:
                    logging.error('DB Exception! %s' % e)
                    db.session.rollback()

            raise ConflictException(
                {'pointer': '/data/attributes/on_site_tickets'},
                "Ticket with id: {} already sold out. You can buy at most {} tickets".format(ticket_id,
                                                                                             ticket.quantity -
                                                                                             ticket_sold_count)
            )

The complete method can be checked here.

References

 

 

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Adding Panel to Add Event Types in Admin Dashboard of Open Event Frontend

This blog will illustrate how to add a new section to admin dashboard of Open Event Frontend which allows admin to add event types. For this we need modals to display a form by which we can edit or add a new event type and we need to create a new route admin/content/events. To create a new route we use ember CLI command:

ember g route admin/content/events

The primary end point of Open Event API with which we are concerned with for creating a new event type or topic is:

GET/POST/DELETE        /v1/event-types

The model concerned with event types is:

 name : attr('string'),
 slug : attr('string'),

 events: hasMany('event')

 

This model is very basic and contains only name and slug and a relationship to event model. Next we want to fetch the existing event types and display them in table. We write queries which fetches data in event-type model in the route file admin/content/events.js.

import Route from '@ember/routing/route';
export default Route.extend({
 titleToken() {
   return this.get('l10n').t('Social Links');
 },
 async model() {
   return {
     'eventTopics': await this.get('store').query('event-topic', {}),
     'eventTypes': await this.get('store').query('event-type', {})
   };
 }
});

 

This will fetch the data in our model. Next we need to display this data in a template for which we define a table that will display each event type.

<button class="ui blue button {{if device.isMobile 'fluid'}}" {{action 'openNewEventTypeModal'}}>{{t 'Add New Event Type'}}</button> 

      <table class="ui celled table">
         <tbody>
           {{#each model.eventTypes as |eventType|}}
             <tr>
               <td>
                 {{eventType.name}}
               </td>
             </tr>
           {{/each}}
         </tbody>
       </table>

 

We have two buttons that are used to edit or delete a event type. Both buttons open up a modal to achieve this functionality. We also have a “Add new Event Type” button at the top. This buttons opens up a modal and sends out a action to its controller when user successfully fills up the name of the event type. Let us take a look at the code of our controller that saves/deletes our event type to server.

addEventType() {
     this.set('isLoading', true);
     this.get('eventType').save()
       .then(() => {
        // Success message
       })
       .catch(()=> {
        //failure message
       })
       .finally(() => {
         this.set('isLoading', false);
       });
   }

 

deleteEventType(eventType) {
     this.set('isLoading', true);
     eventType.destroyRecord()
       .then(() => {
        // Success
       })
       .catch(()=> {
        //failure
       })
       .finally(() => {
         this.set('isLoading', false);
       });
   }

 

In addNewEventType() function we take the data from the form and save the model, which eventually sends POST request to save the new Event Type on server. This returns a JavaScript promise and we handle it via then and catch. It goes to then block if promise resolves and goes to catch is promise rejects/fails.

Similarly in delete function we take the eventType which is passed as model of event-type object and call destroyRecord() function which eventually sends out a DELETE request to server and data gets deleted. Here also we handle the response via resolve and reject depicted with then and catch respectively.

Resources

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Implementing Accepting and Rejecting Proposals in Open Event Frontend

This blog post will illustrate how to add buttons to accept and reject proposal and making them functional. Sessions tab in event dashboard communicates with the following APIs of Open Event Server.

  • GET                    /v1/sessions
  • PATCH              /v1/sessions
What is meant by accepting or rejecting a session in open event?

Sessions are part of event which include one or many speakers. Speakers can propose one or many sessions for a event. Now it is duty of organizer to accept some proposals and reject others. Open event provides two options to accept or reject a proposal i.e. with email or without email.

For this we need to send a key value pair which includes whether we want to send email or not along with other parameters which include current state of session and other important properties. A typical request to alter state of session looks like this.

{
  "data": {
    "attributes": {
      "title": "Micropython Session",
      "level": 1,
      "starts-at": "2017-06-01T10:00:00.500127+00:00",
      "ends-at": "2017-06-01T11:00:00.500127+00:00",
      "created-at": "2017-05-01T01:24:47.500127+00:00",
      "is-mail-sent": false,
      "send-email": true,
    },
    "type": "session",
    "id": "1"
  }
}
Implementing in frontend

We start by providing two buttons for a pending session. One to accept the session and other to reject the session.

On clicking either accept or reject button we get two options to choose i.e. with email and without email. Depending on what organizer chooses a action is fired from the template and sent to controller. Template code for these buttons looks something like this.

class=“ui vertical compact basic buttons”> {{#unless (eq record.state ‘accepted’)}} {{#ui-dropdown class=‘ui icon bottom right pointing dropdown button’}} class=“green checkmark icon”>

class=“menu”>

class=“item” {{action acceptProposal record true}}>{{t ‘With email’}}

 


class=“item” {{action acceptProposal record false}}>{{t ‘Without email’}}

 

      </div>
    {{/ui-dropdown}}
  {{/unless}}
  {{#unless (eq record.state 'rejected')}}
    {{#ui-dropdown class='ui icon bottom right pointing dropdown button'}}
      <i class="red remove icon"></i>

class=“menu”>

class=“item” {{action rejectProposal record true}}>{{t ‘With email’}}

 


class=“item” {{action rejectProposal record false}}>{{t ‘Without email’}}

 

      </div>
    {{/ui-dropdown}}
  {{/unless}}
</div>

We can see that for with email button we trigger accept proposal button with two parameters record and true. Record contains the instance of session and true signifies that we are sending email. Similar is the case with without email button. Controller for these actions looks something like this.

acceptProposal(session, sendEmail) {
      session.set('sendEmail', sendEmail);
      session.set('state', 'accepted');
      session.set('isMailSent', sendEmail);
      this.set('isLoading', true);
      session.save()
        .then(() => {
          sendEmail ? this.notify.success(this.get('l10n').t('Session has been accepted and speaker has been notified via email.'))
            : this.notify.success(this.get('l10n').t('Session has been accepted'));
        })
        .catch(() => {
          this.notify.error(this.get('l10n').t('An unexpected error has occurred.'));
        })
        .finally(() => {
          this.set('isLoading', false);
        });
    },
    rejectProposal(session, sendEmail) {
      session.set('sendEmail', sendEmail);
      session.set('state', 'rejected');
      session.set('isMailSent', sendEmail);
      this.set('isLoading', true);
      session.save()
        .then(() => {
          sendEmail ? this.notify.success(this.get('l10n').t('Session has been rejected and speaker has been notified via email.'))
            : this.notify.success(this.get('l10n').t('Session has been rejected'));
        })
        .catch(() => {
          this.notify.error(this.get('l10n').t('An unexpected error has occurred.'));
        })
        .finally(() => {
          this.set('isLoading', false);
        });
    }

For accepting with email we set sendEmail field to true and send the query to server. Similarly for reject proposal action we follow same procedure.

Conclusion

Implementing buttons like these, and defining proper actions like these we are able to change the state of session with options to send email or not.

Resources

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