GSoC

Read more about the article Reset Password Functionality in SUSI iOS

Reset Password Functionality in SUSI iOS

Reset Password as the name suggests is one of the features in the SUSI iOS app which allows a user to change his/her password when they are logged in. This feature was added because a user would want to change his password sometimes to prevent unauthorized access or make his account security stronger. We can find many popular apps online such as Facebook, Gmail, which allow the user to reset their password. The way this is done is pretty simple and all we need from the user is his current and the new password he/she wants to set. In this blog post, I am going to explain step by step how this is implemented in the iOS client.

Implementation

The option to Reset Password is provided to the user under the Settings Controller. On selecting the row, the user is presented with another view which asks the user for his/her current password, new password, and another field to confirm the newly entered password.

First, the user needs to provide his current password followed by the new password. The user’s current password is required just to authenticate that the account’s owner is requesting the password change. The new password field is followed by another field called confirm password just to make sure there isn’t any typo.

Now when the field is filled, the user clicks the `Reset password` button at the bottom. What happens here is, first, the fields are validated to ensure the correct length of the passwords followed by an API request to update the same. The endpoint for the same is as below:

http://api.susi.ai/aaa/changepassword.json?changepassword=user_email&password=current _pass&newpassword=new_pass&access_token=user_access_token

This endpoint requires 3 things:

  • Current Password
  • New Password
  • User’s email
  • Access Token obtained at the time of login
func validatePassword() -> [Bool:String] {
        if let newPassword = newPasswordField.text,
            let confirmPassword = confirmPasswordField.text {
            if newPassword.characters.count > 5 {
                if newPassword == confirmPassword {
                    return [true: ""]
                } else {
                    return [false: ControllerConstants.passwordDoNotMatch]
                }
            } else {
                return [false: ControllerConstants.passwordLengthShort]
            }
        }
        return [false: Client.ResponseMessages.ServerError]
    }

Initially, we were not saving the user’s email, so we added the user’s email to the User’s object which is saved at the time of login.

if var userData = results {
userData[Client.UserKeys.EmailOfAccount] = user.email
UserDefaults.standard.set(userData, forKey: ControllerConstants.UserDefaultsKeys.user)
self.saveUserGlobally(user: currentUser)
}

At last, the API call is made which is implemented as below:

let params = [
  Client.UserKeys.AccessToken: user.accessToken,
  Client.UserKeys.EmailOfAccount: user.emailID,
  Client.UserKeys.Password: currentPasswordField.text ?? "",
  Client.UserKeys.NewPassword: newPasswordField.text ?? ""
]
Client.sharedInstance.resetPassword(params as [String : AnyObject], { (_, message) in
  DispatchQueue.main.async {
    self.view.makeToast(message)
    self.setUIActive(active: false)
  }
})

Below is the final UI.

Reference

Continue ReadingReset Password Functionality in SUSI iOS
Read more about the article Performing Diode Clipping and Clamping Experiment in PSLab Android

Performing Diode Clipping and Clamping Experiment in PSLab Android

We can perform experiments like diode clipping and clamping using PSLab Android. A circuit which removes the peak of a waveform is known as a clipper. Diode clipper cuts off the top half or lower half or both top and lower half of the input signal. 

Different types of clipping circuits listed below

Different Clipping Experiments

A clamper circuit adds the positive dc component to the input signal to push it to the positive side. Similarly, a clamper circuit adds the negative dc component to the input signal to push it to the negative side. It basically shifts the input signal without changing the shape of the signal.

Different Clamping Experiments

Apparatus

Diode, Resistance, Capacitor (only for diode clamping), Breadboard, Wires and PSLab

Adding Diode Clipping Experiment support in PSLab Android App

To support Diode Clipping Experiment we require generating a sine wave and a dc component. This can be done using W1 and PV1 pins in PSLab device. Both input and output signals can be read using CH1 and CH2. So, when the Diode Clipping Experiment needs to be performed the following code needs to be implemented

scienceLab.setSine1(5000);
scienceLab.setPV1(//progress of the seekbar);

The signals are recorded using Oscilloscope Activity.

Adding Diode Clamping Experiment support in PSLab Android App

Diode Clamping Experiment was implemented similarly to Diode Clipping Experiment. The following are the screenshots of the experiment.     

The following is a glimpse of Diode Clamping Experiment performed using PSLab device using PSLab Android App.

Resources

  1. Read more about Clipper Circuits –
  2. Read more information about Clamping Circuits –
Continue ReadingPerforming Diode Clipping and Clamping Experiment in PSLab Android
Read more about the article Copying Event in Open Event API Server

Copying Event in Open Event API Server

The Event Copy feature of Open Event API Server provides the ability to create a xerox copy of event copies with just one API call. This feature creates the complete copy of event by copying the related objects as well like tracks, sponsors, micro-locations, etc. This API is based on the simple method where an object is first removed is from current DB session and then applied make_transient. Next step is to remove the unique identifying columns like “id”, “identifier” and generating the new identifier and saving the new record. The process seems simple but becomes a little complex when you have to generate copies of media files associated and copies of related multiple objects ensuring no orders, attendees, access_codes relations are copied.

Initial Step

The first thing to copy the event is first to get the event object and all related objects first

if view_kwargs.get('identifier').isdigit():
   identifier = 'id'

event = safe_query(db, Event, identifier, view_kwargs['identifier'], 'event_'+identifier)

Next thing is to get all related objects to this event.

Creating the new event

After removing the current event object from “db.session”, It is required to remove “id” attribute and regenerate “identifier” of the event.

db.session.expunge(event)  # expunge the object from session
make_transient(event)
delattr(event, 'id')
event.identifier = get_new_event_identifier()
db.session.add(event)
db.session.commit()

Updating related object with new event

The new event created has new “id” and “identifier”. This new “id” is added into foreign keys columns of the related object thus providing a relationship with the new event created.

for ticket in tickets:
   ticket_id = ticket.id
   db.session.expunge(ticket)  # expunge the object from session
   make_transient(ticket)
   ticket.event_id = event.id
   delattr(ticket, 'id')
   db.session.add(ticket)
   db.session.commit()

Finishing up

The last step of Updating related objects is repeated for all related objects to create the copy. Thus a new event is created with all related objects copied with the single endpoint.

References

How to clone a sqlalchemy object
https://stackoverflow.com/questions/28871406/how-to-clone-a-sqlalchemy-db-object-with-new-primary-key

Continue ReadingCopying Event in Open Event API Server
Read more about the article Reset password in Open Event API Server

Reset password in Open Event API Server

The addition of reset password API in the Open Event API Server enables the user to send a forgot password request to the server so that user can reset the password. Reset Password API is a two step process. The first endpoint allows you to request a token to reset the password and this token is sent to the user via email. The second process is making a PATCH request with the token and new password to set the new password on user’s account.

Creating a Reset token

This endpoint is not JSON spec based API. A reset token is simply a hash of random bits which is stored in a specific column of user’s table.

hash_ = random.getrandbits(128)
self.reset_password = str(hash_)

Once the user completed the resetting of the password using the specific token, the old token is flushed and the new token is generated. These tokens are all one time use only.

Requesting a Token

A token can be requested on a specific endpoint  POST /v1/auth/reset-password
The token with the direct link will be sent to registered email.

link = make_frontend_url('/reset-password', {'token': user.reset_password})
send_email_with_action(user, PASSWORD_RESET,     
                       app_name=get_settings()['app_name'], link=link)

Flow with frontend

The flow is broken into 2 steps with front end is serving to the backend. The user when click on forget password will be redirected to reset password page in the front end which will call the API endpoint in the backend with an email to send the token. The email received will contain the link for the front end URL which when clicked will redirect the user to the front end page of providing the new password. The new password entered with the token will be sent to API server by the front end and reset password will complete.

Updating Password

Once clicked on the link in the email, the user will be asked to provide the new password. This password will be sent to the endpoint PATCH /v1/auth/reset-password. The body will receive the token and the new password to update. The user will be identified using the token and password is updated for the respective user.

try:
   user = User.query.filter_by(reset_password=token).one()
except NoResultFound:
   return abort(
       make_response(jsonify(error="User not found"), 404)
   )
else:
   user.password = password
   save_to_db(user)

References

  1. Understand Self-service reset password
    https://en.wikipedia.org/wiki/Self-service_password_reset
  2. Python – getrandbits()
    https://docs.python.org/2/library/random.html
Continue ReadingReset password in Open Event API Server
Read more about the article Post Payment Charging in Open Event API Server

Post Payment Charging in Open Event API Server

Order flow in Open Event API Server follows very simple process. On successfully creating a order through API server the user receives the payment-url. API server out of the box provides support for two payment gateways, stripe and paypal.
The process followed is very simple, on creating the order you will receive the payment-url. The frontend will complete the payment through that url and on completion it will hit the specific endpoint which will confirm the payment and update the order status.

Getting the payment-url

Payment Url will be sent on successfully creating the order. There are three type of payment-modes which can be provided to Order API on creating order. The three payment modes are “free”, “stripe” and “paypal”. To get the payment-url just send the payment mode as stripe or paypal.

POST Payment

After payment processing through frontend, the charges endpoint will be called so that payment verification can be done on the server end.

POST /v1/orders/<identifier>/charge

This endpoint receives the stripe token if the payment mode is stripe else no token is required to process payment for paypal.
The response will have the order details on successful verification.

Implementation

The implementation of charging is based on the custom data layer in Orga Server. The custom layer overrides the Base data layer and provide the custom implementation to “create_object” method thus, not using Alchemy layer.

def create_object(self, data, view_kwargs):
   order = Order.query.filter_by(id=view_kwargs['id']).first()
   if order.payment_mode == 'stripe':
       if data.get('stripe') is None:
           raise UnprocessableEntity({'source': ''}, "stripe token is missing")
       success, response = TicketingManager.charge_stripe_order_payment(order, data['stripe'])
       if not success:
           raise UnprocessableEntity({'source': 'stripe_token_id'}, response)

   elif order.payment_mode == 'paypal':
       success, response = TicketingManager.charge_paypal_order_payment(order)
       if not success:
           raise UnprocessableEntity({'source': ''}, response)
   return order

With the resource class as 

class ChargeList(ResourceList):
   methods = ['POST', ]
   schema = ChargeSchema

   data_layer = {
       'class': ChargesLayer,
       'session': db.session
   }

Resources

  1. Paypal Payments API
    https://developer.paypal.com/docs/api/payments/
  2. Flask-json-api custom layer docs
    http://flask-rest-jsonapi.readthedocs.io/en/latest/data_layer.html#custom-data-layer
  3. Stripe Payments API
    https://stripe.com/docs/charges
Continue ReadingPost Payment Charging in Open Event API Server
Read more about the article Implementing Users API to Display the Users at Admin Route in Open Event Frontend

Implementing Users API to Display the Users at Admin Route in Open Event Frontend

This article will illustrate how the users are displayed and updated on the /admin/users route, their roles, user links etc. using the users API in Open Event Frontend. The primary end point of Open Event API with which we are concerned with for fetching the users is

GET /v1/users

First, we need to create a model for the user, which will have the fields corresponding to the API, so we proceed with the ember CLI command:

ember g model user

Next, we need to define the model according to the requirements. The model needs to extend the base model class. As a user can have multiple notifications, orders and  sessions etc. so we have to use ember data relationships “hasMany”. Hence, the model will have the following format.

import ModelBase from 'open-event-frontend/models/base';
import { hasMany } from 'ember-data/relationships';

export default ModelBase.extend({
  email        : attr('string'),
  password     : attr('string'),
  isVerified   : attr('boolean', { readOnly: true }),
  isSuperAdmin : attr('boolean', { readOnly: true }),
  isAdmin      : attr('boolean', { readOnly: true }),
  firstName : attr('string'),
  lastName  : attr('string')
});

The complete code for the model can be seen here

Now, we need to load the data from the API using the above model, so we will send a GET request to the API to fetch the users. This can be easily achieved using this.

return this.get('store').query('user', {'page[size]': 10 });

The above line is querying for the users from the store which is place where cache of all of the records that have been loaded by our application is there. If a route asks for a record, the store can return it immediately if it is there in the cache and we want to display only 10 users in a page so defined how many number of users has to be loaded at a time.

Now we need to filter the users based on whether they are active or they have deleted their accounts. For this purpose, we need to pass filter to the query which will tell what type of users to be loaded at once.

The next thing we need to do is to display the above data fetched from the API into an ember table. Ember table helps in allowing us to render very large data sets by only rendering the rows that are being displayed. For this, we defined a controller class which will help in letting the table know what all columns will be required to display and the attribute values they correspond in the API. We can also define the template for each column. The code for the controller class looks like this.

import Ember from 'ember';

const { Controller } = Ember;
export default Controller.extend({
  columns: [
    {
      propertyName     : 'first-name',
      title            : 'Name',
      disableSorting   : true,
      disableFiltering : true
    },
    {
      propertyName     : 'email',
      title            : 'Email',
      disableSorting   : true,
      disableFiltering : true
     },
     {
      propertyName     : 'last-accessed-at',
      title            : 'Last Accessed',
      template         : 'components/ui-table/cell/admin/users/cell-last-accessed-at',
      disableSorting   : true,
      disableFiltering : true
    }
   ]
});

In the above code, we can see a field called ‘disableSorting’ which is true if we don’t want to sort the table based on that column. Since we want the last-accessed-at column to be customized, so we have separately added a template for the column which will ensure how it will look in the column. The complete code for the other columns which are there in table apart from these can be found here.

Now to display the ember table we will write the following code.

{{events/events-table columns=columns data=model
    useNumericPagination=true
    showGlobalFilter=true
    showPageSize=true
}}

In the above piece of code, we are calling the same ember table as we used in case of events to reduce the code duplication. We are passing the columns and data in the table which remains unique to the table. Next, we are ensuring that our page shows the amount of data we’re fetching at one go, allows the filtering the table based on the columns.

The UI of the users page for the above code snippets look like this.

Fig 1: The UI of the users table under admin/users route

The entire code for implementing the users API can be seen here.

To conclude, this is how we efficiently fetched the users using the Open-Event-Orga users API, ensuring that there is no unnecessary API call to fetch the data and no code duplication using the same ember table again.

Resources:

Continue ReadingImplementing Users API to Display the Users at Admin Route in Open Event Frontend
Read more about the article Configuring Youtube Scraper with Search Endpoint in Loklak Server

Configuring Youtube Scraper with Search Endpoint in Loklak Server

Youtube Scraper is one of the interesting web scrapers of Loklak Server with unique implementation of its data scraping and data key creation (using RDF). It couldn’t be accessed as it didn’t have any url endpoint. I configured it to use both as separate endpoint (api/youtubescraper) and search endpoint (/api/search.json).

Usage:

  1. YoutubeScraper Endpoint: /api/youtubescraperExample:http://api.loklak.org/api/youtubescraper?query=https://www.youtube.com/watch?v=xZ-m55K3FhQ&scraper=youtube
  2. SearchServlet Endpoint: /api/search.json

Example: http://api.loklak.org/api/search.json?query=https://www.youtube.com/watch?v=xZ-m55K3FhQ&scraper=youtube

The configurations added in Loklak Server are:-

1) Endpoint

We can access YoutubeScraper using endpoint /api/youtubescraper endpoint. Like other scrapers, I have used BaseScraper class as superclass for this functionality .

2) PrepareSearchUrl

The prepareSearchUrl method creates youtube search url that is used to scrape Youtube webpage. YoutubeScraper takes url as input. But youtube link could also be a shortened link. That is why, the video id is stored as query. This approach optimizes the scraper and adds the capability to add more scrapers to it.

Currently YoutubeScraper scrapes the video webpages of Youtube, but scrapers for search webpage and channel webpages can also be added.

URIBuilder url = null;
String midUrl = "search/";
    try {
       switch(type) {
           case "search":
               midUrl = "search/";
               url = new URIBuilder(this.baseUrl + midUrl);
               url.addParameter("search_query", this.query);
               break;
           case "video":
               midUrl = "watch/";
               url = new URIBuilder(this.baseUrl + midUrl);
               url.addParameter("v", this.query);
               break;
           case "user":
               midUrl = "channel/";
               url = new URIBuilder(this.baseUrl + midUrl + this.query);
               break;
           default:
               url = new URIBuilder("");
               break;
       }
    } catch (URISyntaxException e) {
       DAO.log("Invalid Url: baseUrl = " + this.baseUrl + ", mid-URL = " + midUrl + "query = " + this.query + "type = " + type);
       return "";
    }

 

3) Get-Data-From-Connection

The getDataFromConnection method is used to fetch Bufferedreader object and input it to scrape method. In YoutubeScraper, this method has been overrided to prevent using default method implementation i.e. use type=all

@Override
public Post getDataFromConnection() throws IOException {
    String url = this.prepareSearchUrl(this.type);
    return getDataFromConnection(url, this.type);
}

 

4) Set scraper parameters input as get-parameters

The Map data-structure of get-parameters fetched by scraper fetches type and query. For URL, the video hash-code is separated from url and then used as query.

this.query = this.getExtraValue("query");
this.query = this.query.substring(this.query.length() - 11);

 

5) Scrape Method

Scrape method runs the different scraper methods (in YoutubeScraper, there is only one), iterate it using PostTimeline and wraps in Post object to the output. This simple function can improve flexibility of scraper to scrape different pages concurrently.

Post out = new Post(true);
Timeline2 postList = new Timeline2(this.order);
postList.addPost(this.parseVideo(br, type, url));
out.put("videos", postList.toArray());

 

References

Continue ReadingConfiguring Youtube Scraper with Search Endpoint in Loklak Server
Read more about the article Adding EditText With Google Input Option While Sharing In Phimpme App

Adding EditText With Google Input Option While Sharing In Phimpme App

In Phimpme Android App an user can share images on multiple platforms. While sharing we have also included caption option to enter description about the image. That caption can be entered by using keyboard as well Google Voice Input method. So in this post, I will be explaining how to add edittext with google voice input option.

Let’s get started

Step-1 Add EditText and Mic Button in layout file

<ImageView
       android:layout_width="20dp"
       android:id="@+id/button_mic"
       android:layout_height="20dp"
       android:background="?android:attr/selectableItemBackground"
       android:background="@drawable/ic_mic_black"
       android:scaleType="fitCenter" />
</RelativeLayout>


Caption Option in Share Activity in Phimpme

In Phimpme we have material design dialog box so right now I am using getTextInputDialogBox(). It will prompt the material design dialog box to enter caption to share image on multiple platform.

Step-2

Now we can get caption from edittext easily using the following code.

if (!captionText.isEmpty()) {
  caption = captionText;
  text_caption.setText(caption);
  captionEditText.setSelection(caption.length());
} else {
  caption = null;
  text_caption.setText(caption);
}


Step – 3 (Now add option Google Voice input option)

To use google input option I have added a global function in Utils class. To use that method just call that method with proper arguments.

public static void promptSpeechInput(Activity activity, int requestCode, View parentView, String promtMsg) {
  Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
  intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL, RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
  intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE, Locale.getDefault());
  intent.putExtra(RecognizerIntent.EXTRA_PROMPT, promtMsg);
  try {
      activity.startActivityForResult(intent, requestCode);
  } catch (ActivityNotFoundException a) {
      SnackBarHandler.show(parentView,activity.getString(R.string.speech_not_supported));
  }

}

Just pass the request code to receive the speech text in onActvityResult() method and passs promt message which will be visible to user.

Step – 4 (Set text to caption )

if (requestCode == REQ_CODE_SPEECH_INPUT && data!=null){
       ArrayList<String> result = data.getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS);
       String voiceInput = result.get(0);
       text_caption.setText(voiceInput);
       caption = voiceInput;
       return;

}

Now we can set the text in caption string right now I am adding text in existing caption i.e If the user enter some text using edittext and after that user clicked on mic button then the extra text will be added after the previous text.

So this is how I have used Google voice input method and made the function globally.

Resources:

Continue ReadingAdding EditText With Google Input Option While Sharing In Phimpme App
Read more about the article Including a Graph Component in the Remote Access Framework for PSLab

Including a Graph Component in the Remote Access Framework for PSLab

The remote-lab software of the pocket science lab enables users to access their devices remotely via the Internet. It includes an API server designed with Python Flask, and a web-app designed with EmberJS that allows users to access the API and carry out various tasks such as writing and executing Python scripts. In a series of blog posts, various aspects of this framework such as  remote execution of function strings, automatic deployment on various domains, creating and submitting python scripts which will be run on the remote server etc have already been explored.  This blog post deals with the inclusion of a graph component in the webapp that will be invoked when the user utilises the `plot` command in their scripts.

The JQPLOT library is being used for this purpose, and has been found to be quite lightweight and has a vast set of example code .

Task list for enabling the plotting feature
  • Add a plot method to the codeEvaluator module in the API server and allow access to it by adding it to the evalGlobals dictionary
  • Create an EmberJS component for handling plots
    • Create a named div in the template
    • Invoke the Jqplot initializer from the JS file and pass necessary arguments and data to the jqplot instance
  • Add a conditional statement to include the jqplot component whenever a plot subsection is present in the JSON object returned by the API server after executing a script
Adding a plot method to the API server

Thus far, in addition to the functions supported by the sciencelab.py instance of PSLab, users had access to print, print_, and button functions. We shall now add a plot function.

def plot(self,x,y,**kwargs):
self.generatedApp.append({"type":"plot","name":kwargs.get('name','myPlot'),"data":[np.array([x,y]).T.tolist()]})

 

The X,Y datasets provided by the user are stacked in pairs because jqplot requires [x,y] pairs . not separate datasets.

We also need to add this to evalGlobals, so we shall modify the __init__ routine slightly:

self.evalGlobals['plot']=self.plot
Building an Ember component for handling plots

First, well need to install jqplot:   bower install –save jqplot

And this must be followed by including the following files using app.import statements in ember-cli-build.js

  • bower_components/jqplot/jquery.jqplot.min.js
  • bower_components/jqplot/plugins/jqplot.cursor.js
  • bower_components/jqplot/plugins/jqplot.highlighter.js
  • bower_components/jqplot/plugins/jqplot.pointLabels.js
  • bower_components/jqplot/jquery.jqplot.min.css

In addition to the jqplot js and css files, we have also included a couple of plugins we shall use later.

Now we need to set up a new component : ember g component jqplot-graph

Our component will accept an object as an input argument. This object will contain the various configuration options for the plot

Add the following line in templates/components/jqplot-graph.hbs:

 style="solid gray 1px;" id="{{data.name}}">

The JS file for this template must invoke the jqplot function in order to insert a complete plot into the previously defined <div> after it has been created. Therefore, the initialization routine must override the didInsertElement routine of the component.

components/jqplot-graph.js

import Ember from 'ember';

export default Ember.Component.extend({
  didInsertElement () {
    Ember.$.jqplot(this.data.name,this.data.data,{
        title: this.title,

        axes: {
          xaxis: {
            tickInterval: 1,
            rendererOptions: {
            minorTicks: 4
            }
          },
        },
        highlighter: {
          show: true, 
          showLabel: true, 

          tooltipAxes: 'xy',
          sizeAdjust: 9.5 , tooltipLocation : 'ne'
        },				  
        legend: {
          show: true,
          location: 'e',
          rendererOptions: {
            numberColumns: 1,
          }
        },
        cursor:{ 
          show: true,
          zoom:true, 
          showTooltip:false
          } 

    });
  }
});

Our component is now ready to be used , and we must make the necessary changes to user-home.hbs in order to include the plot component if the output JSON of a script executed on the server contains it.

The following excerpt from the results modal shows how the plot component can be inserted

{{#each codeResults as |element|}}
	{{#if (eq element.type 'text')}}
		{{element.value}}<br>
	{{/if}}
	{{#if (eq element.type 'plot')}}
		{{jqplot-graph data=element}}
	{{/if}}
{{/each}}

Most of the other components such as buttons and spans have been removed for clarity. Note that the element object is passed to the jqplot-graph component as an argument so that the component may configure itself accordingly.

In conclusion, the following screencast shows what we have created. A simple plot command creates a fancy plot in the output which includes data point highlighting, and can be easily configured to do a lot more. In the next blog post we shall explore how to use this plot to create a persistent application such as an oscilloscope.

Resources:

 

Continue ReadingIncluding a Graph Component in the Remote Access Framework for PSLab
Read more about the article Implementing Sessions API for the event in Open Event Frontend

Implementing Sessions API for the event in Open Event Frontend

This article will illustrate how the sessions are displayed and updated on the events/{event_id}/sessions route to display the sessions available for a particular event using the sessions API in Open Event Frontend. The primary end point of Open Event API with which we are concerned with for fetching the sessions is

GET /v1/sessions/{session_id}

First, we need to create a model for the sessions, which will have the fields corresponding to the API, so we proceed with the ember CLI command:

ember g model session

Next, we need to define the model according to the requirements. The model needs to extend the base model class. As a session can have multiple speakers and a session always belongs to an event, so we have to use ember data relationships “hasMany” and “belongsTo”. Hence, the model will have the following format.

import ModelBase from 'open-event-frontend/models/base';
import { belongsTo, hasMany } from 'ember-data/relationships';

export default ModelBase.extend({
  title         : attr('string'),
  subtitle      : attr('string'),

  speakers      : hasMany('speaker'),
  event         : belongsTo('event')
});

Complete code for the model can be seen here

Now, we need to load the data from the API using the above model, so we will send a GET request to the API to fetch the sessions corresponding to a particular event. This can be easily achieved using this.

return this.modelFor('events.view').query('sessions');

The above line is asking for getting the current model that is on the route events.view and query for the sessions property from that model.

Now we need to filter the sessions based on their sessions whether they have been accepted or confirmed or pending or rejected and display them on different pages. For this purpose, we need to pass filter and pages to the query which will tell what type and now of sessions to be loaded at once. Also, we need to display the speakers associated with session and event details. For this case, the above query will be formatted like this.

return this.modelFor('events.view').query('sessions', {
      include      : 'event,speakers',
    filter       : filterOptions,
      'page[size]' : 10
    });

In the above query, the filterOptions are designed in such a way which check for what type of sessions user is querying for. The code can be found here.

The next thing we need to do is to display the above data fetched from the API into an ember table. For this, we need to have a controller class which will help in letting the table know what all columns will be required to display and the attribute values they correspond in the API. We can also define the template for each column. The code for the controller class looks like this.

export default Controller.extend({
  columns: [
    {
      propertyName   : 'state',
      title          : 'State',
      disableSorting : true,
      template       : 'components/ui-table/cell/events/view/sessions/cell-session-state'
    },
    {
      propertyName : 'title',
      title          : 'Title'
    },
    {
      propertyName    : 'speakers',
      template       : 'components/ui-table/cell/cell-speakers',
      title          : 'Speakers',
      disableSorting  : true
     }]
});

In the above code, we can see a field called ‘disableSorting’ which is true if we don’t want to sort the table based on that column. Since we want the state column to be customized, so we have separately added a template for the column which will ensure how it will look in the column. The complete code for the other columns which are there in table apart from the state, title and speakers can be found here.

Now to display the ember table we will write the following code.

{{events/events-table columns=columns data=model
    useNumericPagination=true
    showGlobalFilter=true
    showPageSize=true
}}
I

In the above piece of code, we are calling the same ember table as we used in case of events to reduce the code duplication. We are passing the columns and data in the table which remains unique to the table. Next, we are ensuring that our page shows the amount of data we’re fetching at one go, allows the filtering the table based on the columns.

The UI of the sessions page for the above code snippets look like this.

Fig 1: The UI of the session table under events/{event_id}/session route

The entire code for implementing the sessions API can be seen here.

To conclude, this is how we efficiently fetched the sessions details using the Open-Event-Orga sessions API, ensuring that there is no unnecessary API call to fetch the data and no code duplication using the same ember table again.

Resources:

Continue ReadingImplementing Sessions API for the event in Open Event Frontend