Implementing Scheduler Actions on Open Event Frontend

After the functionality to display scheduled sessions was added to Open Event Frontend, the read-only implementation of the scheduler had been completed. What was remaining now in the scheduler were the write actions, i.e., the sessions’ scheduling which event organizers do by deciding its timings, duration and venue.

First of all, these actions required the editable flag to be true for the fullcalendar plugin. This allowed the sessions displayed to be dragged and dropped. Once this was enabled, the next task was to embed data in each of the unscheduled sessions so that when they get dropped on the fullcalendar space, they get recognized by the calendar, which can place it at the appropriate location. For this functionality, they had to be jQuery UI draggables and contain an “event” data within them. This was accomplished by the following code:

this.$().draggable({
  zIndex         : 999,
  revert         : true,      // will cause the event to go back to its
  revertDuration : 0  //  original position after the drag
});

this.$().data('event', {
  title    : this.$().text().replace(/\s\s+/g, ' '), // use the element's text as the event title
  id       : this.$().attr('id'),
  serverId : this.get('session.id'),
  stick    : true, // maintain when user navigates (see docs on the renderEvent method)
  color    : this.get('session.track.color')
});

Here, “this” refers to each unscheduled session. Note that the session color is fetched via the corresponding session track. Once the unscheduled sessions contain enough relevant data and are of the right type (i.e, jQuery UI draggable type), they’re ready to be dropped on the fullcalendar space.

Now, when an unscheduled session is dropped on the fullcalendar space, fullcalendar’s eventReceive callback is triggered after its drop callback. In this callback, the code removes the session data from the unscheduled sessions’ list, so it disappears from there and gets stuck to the fullcalendar space. Then the code in the drop callback makes a PATCH request to Open Event Server with the relevant data, i.e, start and end times as well as microlocation. This updates the corresponding session on the server.

Similarly, another callback is generated when an event is resized, which means when its duration is changed. This again sends a corresponding session PATCH request to the server. Furthermore, the functionality to pop a scheduled event out of the calendar and add it back to the unscheduled sessions’ list is also implemented, just like in Eventyay version 1. For this, a cross button is implemented, which is embedded in each scheduled session. Clicking this pops the session out of the calendar and adds it back to the unscheduled sessions list. Again, a corresponding PATCH request is sent to the server.

After getting the response of such requests, a notification is displayed on the screen, which informs the users whether the action was successful or not. The main PATCH functionality is in a separate function which is called by different callbacks accordingly, so code reusability is increased:

updateSession(start, end, microlocationId, sessionId) {
    let payload = {
      data: {
        attributes: {
          'starts-at' : start ? start.toISOString() : null,
          'ends-at'   : end ? end.toISOString() : null
        },
        relationships: {
          microlocation: {
            data: {
              type : 'microlocation',
              id   : microlocationId
            }
          }
        },
        type : 'session',
        id   : sessionId
      }
    };

    let config = {
      skipDataTransform: true
    };
    return this.get('loader')
      .patch(`sessions/${sessionId}`, JSON.stringify(payload), config)
      .then(() => {
        this.get('notify').success('Changes have been made successfully');
      })
      .catch(reason => {
        this.set('error', reason);
        this.get('notify').error(`Error: ${reason}`);
      });
  },

This completes the scheduler implementation on Open Event Frontend. Here is how it looks in action:

scheduler actions.gif

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Open Event Server – Export Speakers as PDF 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 speakers in a very detailed view in the event management dashboard. He can see the statuses of all the speakers. The possible statuses are pending, accepted, and rejected. He/she can take actions such as editing the speakers.

If the organizer wants to download the list of all the speakers as a PDF file, he or she can do it very easily by simply clicking on the Export As PDF button in the top right-hand corner.

Let us see how this is done on the server.

Server side – generating the Speakers PDF file

Here we will be using the pisa package which is used to convert from HTML to PDF. It is a html2pdf converter which uses ReportLab Toolkit, the HTML5lib and pyPdf. It supports HTML5 and CSS 2.1 (and some of CSS 3). It is completely written in pure Python so it is platform independent.

from xhtml2pdf import pisa<

We have a utility method create_save_pdf which creates and saves PDFs from HTML. It takes the following arguments:

  • pdf_data – This contains the HTML template which has to be converted to PDF.
  • key – This contains the file name
  • dir_path – This contains the directory

It returns the newly formed PDF file. The code is as follows:

def create_save_pdf(pdf_data, key, dir_path='/static/uploads/pdf/temp/'):
   filedir = current_app.config.get('BASE_DIR') + dir_path

   if not os.path.isdir(filedir):
       os.makedirs(filedir)

   filename = get_file_name() + '.pdf'
   dest = filedir + filename

   file = open(dest, "wb")
   pisa.CreatePDF(io.BytesIO(pdf_data.encode('utf-8')), file)
   file.close()

   uploaded_file = UploadedFile(dest, filename)
   upload_path = key.format(identifier=get_file_name())
   new_file = upload(uploaded_file, upload_path)
   # Removing old file created
   os.remove(dest)

   return new_file

The HTML file is formed using the render_template method of flask. This method takes the HTML template and its required variables as the arguments. In our case, we pass in ‘pdf/speakers_pdf.html’(template) and speakers. Here, speakers is the list of speakers to be included in the PDF file. In the template, we loop through each item of speakers. We print his name, email, list of its sessions, mobile, a short biography, organization, and position. All these fields form a row in the table. Hence, each speaker is a row in our PDF file.

The various columns are as follows:

<thead>
<tr>
   <th>
       {{ ("Name") }}
   </th>
   <th>
       {{ ("Email") }}
   </th>
   <th>
       {{ ("Sessions") }}
   </th>
   <th>
       {{ ("Mobile") }}
   </th>
   <th>
       {{ ("Short Biography") }}
   </th>
   <th>
       {{ ("Organisation") }}
   </th>
   <th>
       {{ ("Position") }}
   </th>
</tr>
</thead>

A snippet of the code which handles iterating over the speakers’ list and forming a row is as follows:

{% for speaker in speakers %}
   <tr class="padded" style="text-align:center; margin-top: 5px">
       <td>
           {% if speaker.name %}
               {{ speaker.name }}
           {% else %}
               {{ "-" }}
           {% endif %}
       </td>
       <td>
           {% if speaker.email %}
               {{ speaker.email }}
           {% else %}
               {{ "-" }}
           {% endif %}
       </td>
       <td>
           {% if speaker.sessions %}
               {% for session in speaker.sessions %}
                   {{ session.name }}<br>
               {% endfor %}
           {% else %}
               {{ "-" }}
           {% endif %}
       </td>
      …. So on
   </tr>
{% endfor %}

The full template can be found here.

Obtaining the Speakers PDF file:

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

GET - /v1/events/{event_identifier}/export/speakers/pdf

Here, event_identifier is the unique ID of the event. This endpoint starts a celery task on the server to export the speakers of the event as a PDF 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/event1.zip"
  },
  "state": "SUCCESS"
}

The file can be downloaded from the above-mentioned URL.

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Implementing Scheduled Sessions in Open Event Scheduler

Until recently, the Open Event Frontend version 2 didn’t have the functionality to display the already scheduled sessions of an event on the sessions scheduler. Displaying the already scheduled sessions is important so that the event organizer can always use the sessions scheduler as a draft and not worry about losing progress or data about scheduled sessions’ timings. Therefore, just like a list of unscheduled sessions was implemented for the scheduler, the provision for displaying scheduled sessions also had to be implemented.

The first step towards implementing this was to fetch the scheduled sessions’ details from Open Event Server. To perform this fetch, an appropriate filter was required. This filter should ideally ask the server to send only those sessions that are “scheduled”. Thus, scheduled sessions need to be defined as sessions which have a non-null value of its starts-at and ends-at fields. Also, few more details are required to be fetched for a clean display of scheduled sessions. First, the sessions’ speaker details should be included so that the speakers’ names can be displayed alongside the sessions. Also, the microlocations’ details need to be included so that each session is displayed according to its microlocation. For example, if a session is to be delivered in a place named ‘Lecture Hall A’, it should appear under the ‘Lecture Hall A’ microlocation column. Therefore, the filter goes as follows:

let scheduledFilterOptions = [
      {
        and: [
          {
            name : 'starts-at',
            op   : 'ne',
            val  : null
          },
          {
            name : 'ends-at',
            op   : 'ne',
            val  : null
          }
        ]
      }
    ];

 

After fetching the scheduled sessions’ details, they need to be delivered to the fulllcalendar code for displaying on the session scheduler. For that, the sessions need to be converted in a format which can be parsed by the fullcalendar add-on of emberJS. For example, fullcalendar calls microlocations as ‘resources’. Here is the format which fullcalendar understands:

{
        title      : `${session.title} | ${speakerNames.join(', ')}`,
        start      : session.startsAt.format('YYYY-MM-DDTHH:mm:SS'),
        end        : session.endsAt.format('YYYY-MM-DDTHH:mm:SS'),
        resourceId : session.microlocation.get('id'),
        color      : session.track.get('color'),
        serverId   : session.get('id') // id of the session on BE
}

 

Once the sessions are in the appropriate format, their data is sent to the fullcalendar template, which renders them on the screen:

Screen Shot 2018-08-21 at 8.20.27 PM.png

This completes the implementation of displaying the scheduled sessions of an event on the Open Event Scheduler.

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Implementing Unscheduled Sessions List for Event Scheduler

Until recently, Open Event Server didn’t allow the storage of unscheduled sessions. However, having the provision of unscheduled sessions was necessary so that event organizers can easily schedule the unscheduled sessions and keep track of them. Also, it allows them to remove scheduled sessions from the scheduler and place them in the unscheduled sessions list, so that they can be scheduled later. Also, since the unscheduled sessions list was also present in Eventyay version 1, it was decided to have the same in version 2.

The first step was to enable the storage of unscheduled sessions on the server. For this, the starts-at and ends-at fields of the session model were modified to be non-required (earlier they were mandatory). Once this change was done, the next step was to fetch the list of unscheduled sessions on the frontend, from the server. Unscheduled sessions were the ones which had the starts-at and ends-at fields as null. Also, the speakers’ details needed to be fetched so that their names can be mentioned along with sessions’ titles, in accordance with Eventyay version 1. Thus, the following were the filter options for the unscheduled sessions’ fetching:

let unscheduledFilterOptions = [
      {
        and: [
          {
            name : 'starts-at',
            op   : 'eq',
            val  : null
          },
          {
            name : 'ends-at',
            op   : 'eq',
            val  : null
          }
        ]
      }
];
 
let unscheduledSessions = await eventDetails.query('sessions', {
      include : 'speakers,track',
      filter  : unscheduledFilterOptions
    });

 

This gave us the list of unscheduled sessions on the frontend appropriately. After this, the next step was to display this list to the event organizer. For this, the scheduler’s Handlebars template file was modified appropriately. The colors and sizes were chosen so that the list looks similar to the one in Eventyay version 1. Also, the Ember add-on named ember-drag-drop was used to make these unscheduled session components draggable, so that they can be ultimately scheduled on the scheduler. After installing this package and making the necessary changes to the project’s package.json file, the component file for unscheduled sessions was modified accordingly to adapt for the draggable components’ UI. This was the final step and completed the implementation of listing unscheduled sessions.

unscheduled_sessions.gif

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Adding New Arrivals in the Metrics of SUSI.AI

The SUSI Skill CMS homepage contains a lot of metics on the homepage. For example, the highest rated skills, latest skills, most used skills etc. Another important metric is the newly arrived skills in a given period of time, say in last week. This keeps the users updated with the system and allows them to know what work is going on the assistant. This also inspires the skill creators to create more skills.

Update skill listing API

To get the list of recently added skill, first of all, we need a mechanism to sort them in descending order of their creation time. Update the skill listing API ie, ListSkillService.java to sort skills by their creation time. The creation time is stored in “YYYY-MM-DD T M S” format, for ex “2018-08-12T03:11:32Z”. So it can be sorted easily using string comparison function.

Collections.sort(jsonValues, new Comparator<JSONObject>() {
    private static final String KEY_NAME = "creationTime";
    @Override
    public int compare(JSONObject a, JSONObject b) {
        String valA = new String();
        String valB = new String();
        int result = 0;
         try {
            valA = a.get(KEY_NAME).toString();
            valB = b.get(KEY_NAME).toString();
            result = valB.compareToIgnoreCase(valA);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return result;
    }
});

After sorting the skills in descending order of their creation date. We need to filter them based on the time period. For example, if the skills created in last days are required then we need a generalized filter for that. This can be achieved by creating a variable for the starting date of the required time period. Say, if the skill created in last 7 days are required, then the number of milliseconds equivalent to 7 days is subtracted from the current timestamp. All the skills created after this timestamp are added to the result while others are skipped.

if (dateFilter) {
	long durationInMillisec = TimeUnit.DAYS.toMillis(duration);
	long timestamp = System.currentTimeMillis() - durationInMillisec;
	String startDate = new Timestamp(timestamp).toString().substring(0, 10); //substring is used for getting timestamp upto date only
	String skillCreationDate = jsonValues.get(i).get("creationTime").toString().substring(0,10);
	if (skillCreationDate.compareToIgnoreCase(startDate) < 0)
	{
	 continue;
	}
}

This filtering works in the API only when the filter type is set to date and duration in days is passed in the endpoint.

Implement new arrivals on CMS

Create the MenuItems in the sidebar that shows the filter name and add onClick handler on them. The skill listing API with the duration filter is passed to the handler. 3 MenuItems are added:

  • Last 7 Days
  • Last 30 Days
  • Last 90 Days

<MenuItem  value="&applyFilter=true&filter_name=descending&filter_type=date&duration=7"  key="Last 7 Days"
  primaryText="Last 7 Days"
  onClick={event =>
    this.handleArrivalTimeChange(
      event, '&applyFilter=true&filter_name=descending&filter_type=date&duration=7',
    )
  }
/>

Create a handler that listens to the onClick event of the above MenuItems. This handler accepts the API endpoint and calls the loadCards function with it.

handleArrivalTimeChange = (event, value) => {
 this.setState({ filter: value }, function() {
   // console.log(this.state);
   this.loadCards();
 });
};

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Open Event Server – Export Sessions as PDF 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 sessions in a very detailed view in the event management dashboard. He can see the statuses of all the sessions. The possible statuses are pending, accepted, confirmed and rejected. He/she can take actions such as accepting/rejecting the sessions.

If the organizer wants to download the list of all the sessions as a PDF file, he or she can do it very easily by simply clicking on the Export As PDF button in the top right-hand corner.

Let us see how this is done on the server.

Server side – generating the Sessions PDF file

Here we will be using the pisa package which is used to convert from HTML to PDF. It is a html2pdf converter which uses ReportLab Toolkit, the HTML5lib and pyPdf. It supports HTML5 and CSS 2.1 (and some of CSS 3). It is completely written in pure Python so it is platform independent.

from xhtml2pdf import pisa

We have a utility method create_save_pdf which creates and saves PDFs from HTML. It takes the following arguments:

  • pdf_data – This contains the HTML template which has to be converted to PDF.
  • key – This contains the file name
  • dir_path – This contains the directory

It returns the newly formed PDF file. The code is as follows:

def create_save_pdf(pdf_data, key, dir_path='/static/uploads/pdf/temp/'):
   filedir = current_app.config.get('BASE_DIR') + dir_path

   if not os.path.isdir(filedir):
       os.makedirs(filedir)

   filename = get_file_name() + '.pdf'
   dest = filedir + filename

   file = open(dest, "wb")
   pisa.CreatePDF(io.BytesIO(pdf_data.encode('utf-8')), file)
   file.close()

   uploaded_file = UploadedFile(dest, filename)
   upload_path = key.format(identifier=get_file_name())
   new_file = upload(uploaded_file, upload_path)
   # Removing old file created
   os.remove(dest)

   return new_file

The HTML file is formed using the render_template method of flask. This method takes the HTML template and its required variables as the arguments. In our case, we pass in ‘pdf/sessions_pdf.html’(template) and sessions. Here, sessions is the list of sessions to be included in the PDF file. In the template, we loop through each item of sessions and check if it is deleted or not. If it not deleted then we print its title, state, list of its speakers, track, created at and has an email been sent or not. All these fields form a row in the table. Hence, each session is a row in our PDF file.

The various columns are as follows:

<thead>
<tr>
   <th>
       {{ ("Title") }}
   </th>
   <th>
       {{ ("State") }}
   </th>
   <th>
       {{ ("Speakers") }}
   </th>
   <th>
       {{ ("Track") }}
   </th>
   <th>
       {{ ("Created At") }}
   </th>
   <th>
       {{ ("Email Sent") }}
   </th>
</tr>
</thead>

A snippet of the code which handles iterating over the sessions list and forming a row is as follows:

{% for session in sessions %}
   {% if not session.deleted_at %}
       <tr class="padded" style="text-align:center; margin-top: 5px">
           <td>
               {% if session.title %}
                   {{ session.title }}
               {% else %}
                   {{ "-" }}
               {% endif %}
           </td>
           <td>
               {% if session.state %}
                   {{ session.state }}
               {% else %}
                   {{ "-" }}
               {% endif %}
           </td>
           <td>
               {% if session.speakers %}
                   {% for speaker in session.speakers %}
                       {{ speaker.name }}<br>
                   {% endfor %}
               {% else %}
                   {{ "-" }}
               {% endif %}
           </td>
          ….. And so on
       </tr>
   {% endif %}
{% endfor %}

The full template can be found here.

Obtaining the Sessions PDF file:

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

GET - /v1/events/{event_identifier}/export/sessions/pdf

Here, event_identifier is the unique ID of the event. This endpoint starts a celery task on the server to export the sessions of the event as a PDF 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/event1.zip"
  },
  "state": "SUCCESS"
}

The file can be downloaded from the above-mentioned URL.

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Implementing User Email Verification in Open Event Frontend

Open Event Server provides the functionality of user email verification after a user registers, but it was not implemented on Open Event Frontend until recently. For users, this meant they were still not able to verify themselves, even after receiving confirmation links in their inboxes, which were sent by the server. Thus, implementing it on frontend was crucial for a complete user registration workflow.

Since the server had already exposed an endpoint to perform the registration, all that was required on the frontend to be done was to make a call to this endpoint with the necessary data. The entire process can be summarized as follows:

  1. The recently registered user clicks on the verification link she receives on her email
  2. The above step opens the link, which is of the format http://fossasia.github.io/open-event-frontend/verify?token=
  3. As soon as the frontend server receives this request, it extracts the token from the URL query parameter
  4. The token is now sent to the backend server as a patch request
  5. The response of the above request confirms whether the user verification is successful or not, and an appropriate message is displayed

In the frontend code, the above algorithm is spread across 3 files: the router, verify route and verify controller. A new route named /verify was implemented for the user verification, and was registered in the project’s main router.js file. After that, in the verify route, the beforeModel() method is used to trigger the above algorithm before the page is loaded:

// in app/routes/verify.js

beforeModel(transition) {
this.controllerFor('verify').verify(transition.queryParams.token);
}

The main algorithm above is implemented in the verify controller:

// in app/controllers/verify.js
...
queryParams : ['token'],
token       : null,
success     : false,
error       : null,

verify(tokenVal) {
let payload = {
data: {
token: tokenVal
}
};
return this.get('loader')
.post('auth/verify-email', payload)
.then(() => {
this.set('success', true);
})
.catch(reason => {
this.set('error', reason);
this.set('success', false);
});
}
});

 

A template for displaying the success or failure messages to the user was also created. It uses the value of the success boolean set above to decide the message to be displayed to the user. The user registration workflow is now complete and the user sees the following message after clicking on the verification link she receives:

Screen Shot 2018-08-21 at 7.10.43 PM

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Feature to Report a Skill as Inappropriate

There are hundreds of skills on SUSI Skill CMS. News skills are created daily. Often some skills are made only for testing purpose. Also, some skills are published even though they are not completely developed. Further users may also create some skills that are not suitable for all age groups. To avoid this a skill reporting feature has been added on the CMS.

Server side implementation

Create a JSONTray object in DAO.java that stores the reported skill data. These reports are stored in reportedSkill.json.

Then create an API to report a skill as inappropriate. It runs at /cms/reportSkill.json endpoint and accepts the following parameters :

  • Model
  • Group
  • Language
  • Skill name
  • Feedback

A user should be logged in to report a skill as inappropriate, so the minimum user role is set to user.

public ServiceResponse serviceImpl(Query call, HttpServletResponse response, Authorization authorization, final JsonObjectWithDefault permissions) throws APIException {
	String model_name = call.get("model", "general");
	File model = new File(DAO.model_watch_dir, model_name);
	String group_name = call.get("group", "Knowledge");
	File group = new File(model, group_name);
	String language_name = call.get("language", "en");
	File language = new File(group, language_name);
	String skill_name = call.get("skill", null);
	File skill = SusiSkill.getSkillFileInLanguage(language, skill_name, false);
	String skill_feedback = call.get("feedback", null);
}

Next search for the reported skill in reportedSkill.json through DAO object. If it is found then add a new report object to it else create a new skill object containing the report and store it in the reportedSkill.json.

JSONObject reportObject = new JSONObject();
Timestamp timestamp = new Timestamp(System.currentTimeMillis());
if (authorization.getIdentity().isEmail()) reportObject.put("email", idvalue);
if (authorization.getIdentity().isUuid()) reportObject.put("uuid", idvalue);
reportObject.put("feedback", skill_feedback);
reportObject.put("timestamp", timestamp.toString());
reports.put(reportObject);
skillName.put("reports", reports);

Also, increment the counter of the total number of reports on the skill. This helps in getting better an overview of the skill and in future may also help in taking automatic actions on the reported skills.

Finally, add the API to SusiServer.java

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Upgrading Open Event to Use Sendgrid API v3

Sendgrid recently upgraded their web API to send emails, and support for previous versions was deprecated. As a result, Open Event Server’s mail sending tasks were rendered unsuccessful, because the requests they were sending to Sendgrid were not being processed. On top of that, it was also found out later that the existing Sendgrid API key on the development server was expired. This had to be fixed at the earliest because emails are a core part of Open Event functionality.

The existing way for emails to be sent via Sendgrid used to hit the endpoint “https://api.sendgrid.com/api/mail.send.json” to send emails. Also, the payload structure was as follows:

payload = {
    'to': to,
    'from': email_from,
    'subject': subject,
    'html': html
}

Also, a header  “Authorization”: “Bearer ” accompanied the above payload. However, Sendgrid changed the payload structure to be of the following format:

{

“personalizations”: [

{“to”: [

{“email”: “[email protected]“}

]

}

],

“from”: {

“email”: “[email protected]

},

“subject”: “Hello, World!”,

“content”: [

{

“type”: “text/plain”,

“value”: “Heya!”

}

]

}

Furthermore, the endpoint was changed to be “https://api.sendgrid.com/v3/mail/send”. To incorporate all these changes with the minimum number of modified lines in the codebase, it was required for that the structure change itself happens at a fairly low level. This was because there are lots of features in the server that perform a wide variety of email actions. Thus, it was clear that changing all of them will not be the most efficient thing to do. So the perfect place to implement the API changes was the function send_email() in mail.py, because all other higher-level email functions are built on top of this function. But this was not the only change, because this function itself used another function, called send_email_task() in tasks.py, specifically for sending email via Sendgrid. So, in conclusion, the header modifications were made in send_email() and payload structure as well as endpoint modifications were made within send_email_task(). This brought the server codebase back on track to send emails successfully. Finally, the key for development server was also renewed and added to its settings in the Heroku Postgres database.

Screenshots:

Screen Shot 2018-08-21 at 3.40.12 PM.png

Screen Shot 2018-08-21 at 3.40.32 PM.png

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Implementing Checkout Times for Attendees on Open Event Server

As of this writing, Open Event Server did not have the functionality to add, manipulate and delete checkout times of attendees. Event organizers should have access to log and update attendee checkout times. So it was decided to implement this functionality in the server. This boiled down to having an additional attribute checkout_times in the ticket holder model of the server.

So the first step was to add a string column named checkout_times in the ticket holder database model, since this was going to be a place for comma-separated values (CSV) of attendee checkout times. An additional boolean attribute named is_checked_out was also added to convey whether an attendee has checked out or not. After the addition of these attributes in the model, we saved the file and performed the required database migration:

To create the migration file for the above changes:

$ python manage.py db migrate

To upgrade the database instance:

$ python manage.py db upgrade

Once the migration was done, the API schema file was modified accordingly:

class AttendeeSchemaPublic(SoftDeletionSchema):
    """
    Api schema for Ticket Holder Model
    """
    
    checkout_times = fields.Str(allow_none=True)  # ←
    is_checked_out = fields.Boolean()  # ←
    

After the schema change, the attendees API file had to have code to incorporate these new fields. The way it works is that when we receive an update request on the server, we add the current time in the checkout times CSV to indicate a checkout time, so the checkout times field is essentially read-only:

from datetime import datetime
...
class AttendeeDetail(ResourceDetail):
    def before_update_object(self, obj, data, kwargs):
        
        if 'is_checked_out' in data and data['is_checked_out']:
        ...
        else:
            if obj.checkout_times and data['checkout_times'] not in \
obj.checkout_times.split(","):
                data['checkout_times'] = '{},{},{}'.format(
                    obj.checkout_times,
                    data['checkout_times'],
                    datetime.utcnow())

 

This completes the implementation of checkout times, so now organizers can process attendee checkouts on the server with ease.

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