Conference Organization App API Project

Project overview

This is project #4 of Udacity's Full Stack Web Developer Nanodegree. The task is to add API functionalities to a WSGI web application for conference organization. The Web Service Api is coded in Python 2.7 and hosted on Google App Engine. A fully functional basic API and the frontend were provided by Udacity.

The API supports the following fuctionalities:

• User authentication (via Google accounts)
• User profiles, including Session wishlists
• Conference information
• Session information
• Speaker information

Setup Instructions

1. Update the application value in app.yaml with the app ID you have registered in the App Engine admin console.
2. Update the values at the top of settings.py to reflect the respective client IDs you have registered in the Developer Console.
3. Update the value of CLIENT_ID in static/js/app.js to the Web client ID.
4. Deploy your application.
5. Test API functionalities using the Google Api Explorer

New API Functionalities

This follows the project tasks assigned by Udacity.

Task 1: Add Sessions to a Conference

To complete this task, the following functionalities were implemented:

• Session and SessionForm classes in models.py
• createSession() API endpoint
• getConferenceSessions() API endpoint
• getConferenceSessionsByType() API endpoint
• getSessionsBySpeaker() API endpoint
• Speaker and SpeakerForm classes in models.py
• addSpeaker() API endpoint
• allSpeakers() API endpoint

Session and SessionForm classes

Sessions are created as datastore entities with the following properties:

Property	Type
name	string, required
highlights	string
speakerName	string
speakerKey	string
duration	integer
typeOfSession	string, repeated
date	date
startTime	time
organizerUserId	string

All above values, except for organizerUserId, are entered using SessionForm. Additionally, SessionForm takes the websafe key of the conference that the session that is being created belongs to.

createSession() API endpoint

createSession() is an endpoint in conference.py that is used to create session entities with the above properties in the datastore.

The logged in user's identity is matched with the conference organizer's id (organizerUserId). Only the owner of the conference may create sessions for it.

A parent-child relationship is set between the conference key and the session key when the session key is being generated.

getConferenceSessions() API endpoint

getConferenceSessions() is an ndb query that takes a websafe conference key as input and returns all the sessions registered under it.

getConferenceSessionsByType() API endpoint

getConferenceSessionsByType() is an ndb query that takes a websafe conference key and session type as inputs and returns all sessions that meet both criteria.

getSessionsBySpeaker() API endpoint

getSessionsBySpeaker() is an ndb query that takes a speaker's name as string as input and returns all sessions that have that speaker, across all conferences.

Speaker and SpeakerForm classes

Speakers are created as datastore entities with the following properties:

Property	Type
Displayname	string, required
profileKey	string
biography	string

All above values are entered using SpeakerForm. profileKey is an optional value that may be entered if speaker is also an attendee with a profile key.

Upon introducting speaker entities, I also updated _createSessionObject() in conference.py to check that the entered speaker key exists and the speaker's name.

addSpeaker() API endpoint

addSpeaker() is an endpoint in conference.py used to create the speaker entity with the above properties in the datastore.

allSpeakers() API endpoint

allSpeakers() is an ndb query that returns all registered speakers.

Task 2: Add Sessions to User Wishlist

To complete this task, the following functionalities were implemented:

• addSessionToWishlist() API endpoint
• getSessionsInWishlist() API endpoint

The chosen approach for implementing session wishlists is based on making wishlists an element of user profile entitites, where a user's wishlist is a list of session keys.

addSessionToWishlist() API endpoint

addSessionToWishlist() takes a websafe session key as input and appends that key to the list of keys contained in the sessionWishlistKeys element within their profile.

Any user may add any conference session to their wishlist, regardless of whether they are registered to attend the conference their desired sessions belong to or not.

getSessionsInWishlist() API endpoint

getSessionsInWishlist() returns a list of all the sessions saved in a user's wishlist simply by retrieving the keys listed in the user's profile's sessionWishlistKeys.

Task 3: Work on indeces and queries

To complete this task, the following functionalities were implemented:

• sessionsMaxDuration() API endpoint
• sessionsStartTime() API endpoint
• getEarlyNonWorkshopSessions() API endpoint (problem solution)
• Manually updated index.yaml with indices to support new endpoint queries

sessionsMaxDuration() API endpoint

sessionsMaxDuration() takes as input the desired maximum duration of a session maxDuration and returns all sessions with duration less or equal to that value.

sessionsStartTime() API endpoint

sessionsStartTime() takes a starting time timeSTR as input and returns all existing sessions that commence at that exact time.

getEarlyNonWorkshopSessions() API endpoint (problem solution)

The problem: the problem presented by having to select sessions that are of a certain type e.g. not workshops, and that commence earler than a certain time e.g. 7pm is that potentially requires setting multiple inqualities on different fields in a ndb query. This is not supported by Google App Engine and can return the error: 'BadRequestError: Only one inequality filter per query is supported`.

Possible solution: a solution to this problem is to only set one of the two conditions in the ndb query in the form of an inequality, and return all sessions that match this first condition. The results obtained are can be then filtered through iteration in Python, where additional conditions can be applied in a for loop. getEarlyNonWorkshopSessions() is an implementation of a proposed solution following this approach.

Updated index.yaml with indices

I manually updated the indeces in index.yaml to support all the Session queries introduces by the new endpoints created and listed above.

Task 4: Add a Task

To complete this task, the following functionalities were implemented:

• cacheFeaturedSpeaker() API endpoint
• getFeaturedSpeaker() API endpoint

cacheFeaturedSpeaker() API endpoint

cacheFeaturedSpeaker() loads a 'featured speaker' message into Memcache via createSession(). In _createSessionObject(), before a new session is created, the speakers' name is added as a featured speakers if the speaker has at least one other session scheduled. The speaker's name entry into Memcache is handled using App Engine's Task Queue.

getFeaturedSpeaker() API endpoint

getFeaturedSpeaker() returns the current featured speaker message loaded into Memcache. If no speaker is featured yet, "Featured speakers to be announced soon" is set in Memcache instead.